Method for providing a glyphosate tolerant bryophyte

Abstract

The present invention relates to a glyphosate-sensitive bryophyte with reduced expression of the gene encoding UDP-N-acetylglucosamine enolpyruvyl transferase (MurA); and / or reduced MurA activity relative to a corresponding wild-type glyphosate tolerant bryophyte. The invention also related to methods of generating said glyphosate-sensitive bryophyte, and methods of using said glyphosate-sensitive bryophyte in screening candidate compounds for EPSPS inhibitor activity. The invention also relates to the use of the MurA gene in providing resistance against EPSPS inhibitors, and a transgenic plant comprising a MurA transgene.

Description

[0001]METHOD Field of the Invention The invention relates to the field of herbicides. More specifically, the present invention relates to the development of a glyphosate-sensitive bryophyte, methods of generating such bryophytes, and the use of such bryophytes in the identification of inhibitors of 5-enolpvruvvl shikimate-3-phosphate synthase (EPSPS). The invention also relates to methods of screening candidate compounds for EPSPS inhibitor activity, the use of the MurA gene for providing resistance against EPSPS inhibitors and a transgenic plant comprising a transgene. Cross reference to related application This application claims priority from GB 2409811.3 filed on 5 July 2024, the contents of which are hereby incorporated by reference. Background of the Invention Herbicides are compounds that are toxic to plants and result in inhibited growth or death of unwanted vegetation. There is a need for new herbicides and new herbicide modes of action, due to an over-dependence on a small number of herbicides, a lack of development of new herbicides (no herbicides with novel modes of action have been introduced since the early 1980s), and toxicity and detrimental environmental impacts of current herbicides. EPSPS is an ideal herbicide target because the enzyme is not present in animals. This decreases the risk that EPSPS inhibitors would disrupt metabolic processes in animals and humans. EPSPS activity is inhibited by glyphosate, which is listed to be withdrawn from the market. However, because a glyphosate substitute is not available, its registration has been temporarily extended. Therefore, there is an urgent demand for technologies and discovery platforms that will identify EPSPS-specific inhibitors. These molecules would then be the starting point of a research and development program to produce an EPSPS-targeted herbicide. Glyphosate is a broad-spectrum herbicide that kills most vascular plant weeds but has ineffective against many bryophytes. It has been extensively used to control the growth of vascular plant weeds in agricultural, urban, and domestic environments and is the most used of all herbicides globally. Glyphosate competitively inhibits the enolpyruvyl transferase enzyme EPSPS. EPSPS catalyzes the production of EPSP – an intermediate in the shikimate pathway – from shikimate-3-phospate (S3P) and phosphoenolpyruvate (PEP) substrates. While glyphosate is known to inhibit EPSPS, the exact cause of glyphosate-induced death in plants is unknown. S3P accumulates when glyphosate-sensitive plants are treated with glyphosate, which is then dephosphorylated to shikimate. Lower levels of shikimate accumulate in glyphosate-treated plants that have evolved resistance or are naturally tolerant to glyphosate. Consequently, shikimate accumulation levels after glyphosate treatment have become a useful biomarker to indicate glyphosate sensitivity or resistance, respectively. The Marchantia polymorpha platform has been successfully deployed to identify molecules that cause death and are therefore potential herbicide lead molecules. However, the platform cannot be used to identify molecules that inhibit EPSPS, because wild type Marchantia polymorpha is not sensitive to treatment with glyphosate, i.e. glyphosate does not repress growth or cause catastrophic death of Marchantia polymorpha. Therefore, small molecules that inhibit EPSPS activity cannot be identified using this platform. There is therefore a need to modify this platform to enable the identification of EPSPS inhibitors. Summary of the Invention The inventors have discovered why Marchantia polymorpha is tolerant to glyphosate. The production of 5-enolpyruylshikimate-3-phosphate (EPSP) by EPSPS from shikimate-3 phosphate (S3P) and phosphoenolpyruvate (PEP) is inhibited by glyphosate. The inventors have identified that another protein, MurA, catalyses the same reaction. Overexpression of Marchantia MurA protein in the angiosperm Arabidopsis thaliana has been found to make this plant glyphosate resistant while controls are highly sensitive. The data are consistent with the hypothesis that MurA confers glyphosate tolerance in Marchantia polymorpha. Thus, there are two independent mechanisms of EPSP synthesis in Marchantia polymorpha; the canonical mechanism via EPSPS and the mechanism discovered by the inventors via MurA. The MurA- dependent mechanism is blocked in MurA loss-of-function mutants. Based on these discoveries, the inventors have devised a novel approach for identifying small molecule EPSPS inhibitors. The invention provides a glyphosate-sensitive bryophyte, wherein the bryophyte has: (a) reduced expression of the gene encoding UDP-N-acetylglucosamine enolpyruvyl transferase (MurA); and / or (b) reduced MurA activity; relative to a corresponding wild-type glyphosate- tolerant bryophyte. The invention also provides a method of generating the glyphosate-sensitive bryophyte of the invention, wherein the method comprises targeted mutagenesis. The invention additionally provides a vector comprising a guide RNA (gRNA), wherein said gRNA is targeted to the MurA gene. The invention also describes the use of the bryophyte of the invention for identifying inhibitors of 5-enolpyruvylshikimate 3-phosphate synthase (EPSPS). The invention also provides a method of screening candidate compounds for EPSPS inhibitor activity, the method comprising the steps of: (i) applying one or more different candidate compounds to the glyphosate-sensitive bryophyte of the invention; and (ii) determining the phenotypic response of the glyphosate-sensitive bryophyte, optionally wherein the phenotypic response is reduced growth or death. The invention also describes the use of the MurA gene for providing resistance against EPSPS inhibitors. The invention also provides a transgenic plant comprising a transgene, wherein said transgene comprises MurA. Brief Description of the Figures Figure 1 shows the impact of glyphosate on different bryophytes including Marchantia polymorpha, Lunularia cruciata and Physcomitrium patens in comparison to Arabidopsis thaliana. (A) shows dose responses of the plant areas of A. thaliana, M. polymorpha, L. cruciata and P. patens plants grown for 21-days on glyphosate treated plates. Error bars are ±SE. (B) shows Brightfield images of individual plants from each species on 5 selected doses of glyphosate taken with a Keyence VHX-7000 microscope. No A. thaliana plant germinated at 100 μM glyphosate. Scale bars are 5 mm. (C) shows dose-response curves of relative activities of purified EPSPS enzymes from A. thaliana and M. polymorpha at varying glyphosate concentrations. The data are fitted with a four-parameter log-logistic regression curve. Error bars are ±SE. (D) shows absolute values of glyphosate in the tissues of 14-day old A. thaliana and M. polymorpha plants, measured using LC-MS / MS, after treatment with 5 μM of glyphosate for 2 and 7days. Error bars are ±SE. (E) shows shikimate and (F) S3P, where ion counts were measured in A. thaliana and M. polymorpha plants grown on media supplemented with 5 μM glyphosate 2-days using LC-MS / MS and the fold changes calculated. Error bars represent SE. Statistical significances are based on Welch’s t-tests. ** = p < 0.001, ns = not significant. Figure 2 shows schematics of EPSPS and MurA from M. polymorpha and their similarities. (A) shows AlphaFold prediction of the EPSPS enzyme from M. polymorpha. (B) shows AlphaFold prediction of the MurA enzyme from M. polymorpha. (C) shows an overlay of the EPSPS and MurA enzymes from M. polymorpha produced in USCF ChimeraX using the matchmaker function. AlphaFold per residue confidence score (pLDDT) between 0 and 100. Colour denotes confidence in the prediction: Dark blue = Very high (pLDDT > 90); Light blue = Confident (90 > pLDDT > 70); Yellow = Low (70 > pLDDT > 50); Orange = Very low (pLDDT < 50). (D) shows a phylogenetic tree based on Maximum Likelihood statistics with collapsed clades representing the evolution of EPSPS and MurA based on the full tree presented in Figure 7. (E) shows a species tree based on1-3. Presence or absence of EPSPS and MurA in each species was determined using BLASTp searches with the amino acid sequence of each enzyme from M. polymorpha as a query. Green depicts presence, red absence, and the number of enzyme paralogs when present is given. Figure 3 shows (A) Plant area ratios of M. polymorpha wild-type (Tak-1 and Tal-2) and MpmurA loss-of-function lines grown on 0 μM and 5 μM of glyphosate for 14 days. The auto- fluorescing areas were measured and the ratios between the treated and untreated plants calculated and plotted. Error bars are ±SE. (B) shows Brightfield images of individual Tak-2 and MpmurA-10 plants on control and 5 μM glyphosate media taken with a Keyence VHX-7000 microscope. Scale bars are 5 mm. (C) shows the relative expression of MpMurA in M. polymorpha MpmurA lines compared to Tak-2 calculated from fold-differences in mRNA abundance. (D) shows plant area ratios of M. polymorpha wild-type and MpMurA overexpression lines. Plants were grown on 0 μM and 10 μM of glyphosate and the auto- fluorescing areas used to measure the ratio between treated and untreated plants. Error bars ±SE. (E) shows Brightfield images of individual Empty vector control andpro35S:MpMurA-3 plants on control and 20 μM glyphosate media taken with a Keyence VHX-7000 microscope. Scale bars are 5 mm. (F) shows the relative expression of MpMurA andpro35S:MpMurA in M. polymorpha MpMurA overexpression lines compared to compared to the MpMurA expression in Empty vector control, calculated from fold-differences in mRNA abundances. (G) shows plant area ratios of A. thaliana wild-type and A. thaliana lines expressing MpMurA grown on 0 μM and 5 μM of glyphosate for 14 days. The auto-fluorescing areas were measured and the ratios between the treated and untreated plants calculated and plotted. Error bars are ±SE. (H) shows Brightfield images of individual Empty vector control andpro35S:MpMurA-2H plants on control and 5 μM glyphosate media taken with a Keyence VHX-7000 microscope. Scale bars are 2.5 mm. (I) shows the relative expression of MpMurA inpro35S:MpMurA A. thaliana lines compared to the expression of UBC21, calculated from fold-differences in mRNA abundance. All tests of statistical differences were Brown-Forsythe and Welch ANOVA performed using Tak-2 or empty vector control plant area treated with glyphosate, relative to control as the baseline: * = p < 0.05, ** = p < 0.01, *** = p < 0.001, **** = p < 0.00001, n.s. = not significant. Figure 4 provides images of MurA chloroplasts and chloroplast measurements to demonstrate size and growth. (A-F) show stereomicroscope images of chloroplasts in 3-day old gemmae from Tak-1 (A), MpmurA-10 (B), MpmurA-8 (C), MpmurA-15 (D) MpmurF-9 (E), and MpmurF-12 (F) lines. (G-J) show Violin plots of chloroplast and cell measurements of wild- type (Tak-1) and MpmurA and MpmurF loss-of-function mutants calculated using the image analysis software FIJI. The chloroplast longest axis (G), shortest axis (H), chloroplast abundance per cell (I), and chloroplast abundance per unit area of cell (J) were measured or calculated. A Brown-Forsythe and Welch ANOVA multiple comparison test was performed to compare values in MpmurA and MpmurF mutants to Tak-1. **** = p < 0.0001). (K) shows M. polymorpha wild- type and MpmurF loss-of-function lines were grown on 0 μM and 5 μM of glyphosate. The auto- fluorescing areas were measured and the ratio between the treated and untreated plants calculated and plotted. Error bars are ±SE. Brown-Forsythe and Welch ANOVA were performed using Tak-1 and Tak-2 area relative to control as baselines. ns = not significant. Figure 5 shows a comparison between MurA and EPSPS function. (A) shows the enzymatic activity of MpEPSPS and MpMurA with the substrates S3P and PEP and of MpMurA with UDP-GlcNAc and PEP measured as μmol phosphate produced / min of reaction time / mg of enzyme (U / mg). (B) shows a MS / MS spectrum of the precursor ion m / z 323.1 in the negative ion mode. Using a collision energy of 20 eV, we observed fragments at m / z 79 and m / z 97, characteristic of phosphorylated metabolites. (C) shows SRM chromatograms of 5- enolpyruvylshikimate-3-phosphate (EPSP) assayed in reaction mixes containing S3P and PEP with MpEPSPS, MpMurA and no enzyme. EPSP was only identified when either MpEPSPS or MpMurA were present. (D) shows the quantity of EPSP measured with LC-MS / MS when S3P and PEP were incubated with MpEPSPS, MpMurA and no enzyme. (E) shows a dose response curve of the relative accumulation of EPSP measured by LC-MS / MS when S3P and PEP were incubated with MpEPSPS and MpMurA along with varying concentrations of glyphosate. The data are fitted with a four-parameter log-logistic regression curve. (F) shows the IC50of MpMurA for glyphosate was significantly lower than that of MpEPSPS (Welch’s t-test, p = 0.0445). Figure 6 shows the enzyme kinetics of M. polymorpha and A. thaliana EPSPS enzymes and glyphosate, S3P and shikimate levels in plant tissues. (A) shows a Michaelis-Menten curve of M. polymorpha EPSPS for S3P substrate. (B) shows a Michaelis-Menten curve of A. thaliana EPSPS for S3P substrate. (C) shows a Michaelis-Menten curve of M. polymorpha EPSPS for PEP substrate. (D) shows a Michaelis-Menten curve of A. thaliana EPSPS for PEP substrate. (E) provides a table summarising the kinetic parameters of M. polymorpha and A. thaliana EPSPS proteins. Standard errors are in parantheses. (F) shows the glyphosate quantity in ion counts in the thalli and leaves of M. polymorpha and A. thaliana respectively following 2 days of glyphosate treatment. (G) shows the shikimate quantity in ion counts in the thalli and leaves of M. polymorpha and A. thaliana respectively following 2 days of glyphosate treatment or in control plants. These data were used to calculate shikimate fold changes in Fig.1 E. (H) shows the S3P quantity in ion counts in the thalli and leaves of M. polymorpha and A. thaliana respectively following 2 days of glyphosate treatment or in control plants. These data were used to calculate S3P fold changes in Fig.1 F. (I) shows the absolute quantity of S3P in control M. polymorpha and A. thaliana plants. Figure 7 shows that MurA proteins evolved from an EPSPS-like protein in the bacterial lineage, which has been displayed using an unrooted maximum likelihood tree of MurA amino acid sequences from Archaeplastida, bacteria and archaea species. The protein sequences were aligned using MAFFT with the L-INS-i algorithm. The phylogenetic tree was constructed using PhyML 3.0, using an estimated gamma distribution model and the WAG+G+I model of amino acid substitution4. Support values presented are from a Chi2-based aLRT test. Figure 8 shows that few angiosperms encode MurA and angiosperm MurAs are subtly different from non-angiosperm streptophyte MurAs. (A) provides a species tree based on5-10. The presence or absence of EPSPS and MurA in each species was determined using BLASTp searches with the amino acid sequence of each enzyme from M. polymorpha as a query. Green depicts presence, red absence, and the number of enzyme paralogs when present is given. (B) shows multiple amino acid sequence alignments of angiosperm (green) and non-angiosperm streptophyte (blue) MurAs surrounding the residues Lys22 and Cys115 which are essential for catalysis. These residues are conserved however some differences in the surrounding residues can be seen. (C) shows the structural comparison of AlphaFold predictions of Solanum tuberosus (pink) and M. polymorpha (blue) of the region surrounding Cys115. (D) shows the AlphaFold prediction of the MurA enzyme from M. polymorpha. (E) shows the AlphaFold prediction of the MurA enzyme from S. tuberosus. (F) shows the overlay of the MurA enzymes from M. polymorpha (blue) and S. tuberosus (pink) produced in USCF ChimeraX using the matchmaker function. Figure 9 shows the generation of predicted loss-of-function mutation in MpMurA by CRISPR / Cas9 mutagenesis and chlorsulfuron sensitivity assay. (A) shows how MpmurA mutant lines were generated using the CRISPR-Cas9 mutagenesis system with two guide RNAs designed to target the first exon of the MpMurA gene carried by a vector containing the Cas9 gene which were transformed into M. polymorpha spores. (B) provides a summary of the nature of the mutations induced in MpMurA induced by CRISPR-Cas9 mutagenesis. (C) shows plant area ratios of M. polymorpha wild-type and MpmurA loss-of-function lines grown on 0 nM and 20 nM of chlorsulfuron for 14 days. The auto-fluorescing areas were measured and the ratios between the treated and untreated plants calculated and plotted. Error bars are ±SE. Figure 10 shows the generation of predicted loss-of-function mutation in MpMurF by CRISPR / Cas9 mutagenesis and a dose-response assay to glyphosate for 2 putative mutants. (A) shows shows MpmurF mutant lines were generated using the CRISPR-Cas9 mutagenesis system with two guide RNAs designed to target the first exon of the MpMurF gene carried by a vector containing the Cas9 gene which were transformed into M. polymorpha spores. (B) provides a summary of the mutations induced in MpMurF induced by CRISPR-Cas9 mutagenesis. (C) shows the dose response curves of the plant areas of M. polymorpha wild-type and MpmurF loss-of-function plants grown for 14 days on glyphosate treated plates. The data are fitted with four-parameter log-logistic regression curves. Error bars are ±SE. Figure 11 provides SRM chromatograms of PEP and S3P. Brief Description of the Sequences SEQ ID NO: 1 – The nucleotide sequence of Marchantia polymorpha MurA gene: agaaaggtgggatatgctgagcttgggcttttgtcgaagaaactgcacagaaatggtgcgcaaattgacgaggtttctggcacaagtgttca ctcctgcccccacgtggtcctctgcctgcgcctctgccaaatcttgctctgcgggttcattcctctgtcgagctcgctcgactccttccttcgctc ggacctcctgccgctgctcgcttgcaggcgtcgctgctcgcaggaatggaggcatgcatgttgcgacattgccgtgacctcgtgtttaaccc gggcttctggggatgaggatgagcagcagcagcagcaacagcagcggcagtgtgaagcgaagggcgggccctggagttttttcactgg ggatgcgaattcgtaacctagggctatttcaactgtcggggaggatgagcttgtcgcattgctcggtcttgccccgggaggagtcggcgttct gtgtgtgttgccagaatggaattgtgaccgagctcttggatctcagctgggcgaatgacgtttttttgtcggtgattttgaaaccggtctgatcaa tgtgcgtttgaattgcgagccagacgagtgggatcttttgtcaccatgatgcgcgctcagatgacttcagcgtcctcctgctggcctgtacgaa attcgagcattccgggcttggtagctcacaatctttctccccctcaggtccctggagttcaaagtgacaatggtgtgtttggaagcaggacgg ggctactcgtcgaatgcctcgaagtctcgggtgggagcaaactttctggccatgtcggaataagtggagccaagaattcggcgttggctgtt ttggctggagctctatgttcagaagaggagctgaatttgaaaatgatacccgacttgcatgacattcaaaggatggttcaggttcttcaatctgt aggggtgaaagtgaagcgttctgcctctggtctcacagtcgacgcgagcgaaattgtctcagtagagccttgtccggaagtagttaggaaat taagagctagttttttcgtcattggagctttagtaggacggaagggcgaagccgtcgttcccctccccggaggatgcgacataggagctcgg cccatcgatcttcacgtgcgtggactgcgagctctgggtgcccaggtggagataaggtaacgagcgctgctaactctgcgtagctggctttg catttgatttttcgagtctgcaccccagcgaaggttgtaggcactttgttgtcttgacttagcacttgtgctgcattgtagatcagttgttccttgtgt catttagacaccgcctcatgattcttggcatccgtaattagaaaactttgagaatatcgcgatgaaccgtttctgtgacgtctctgtgtctctgaac acttcacttgcagagagctggacctttatgcaaccattatccagaaaaatgcccccgccttgaggactgcagtatttcttctgtgcaattgttaac ggtcagcttcgtgatattaaattgcatttgtaactatgcaggcaagacaaggtttatgcacgtgcatctcatggtaagagattagtagggggca aatttcatcttgattatccaagtgttggcgccactgaaaccctcatgatggctgcctctttggcagacggagaaaccgtactgtcaaatgtggct caggtgtggccacattgctcgctgttttgctgtgacaaattcgctgcttgttgtagataattgtgacatagatcaagaggtggtactcgttatgat gaagagtggagtggattcttagagtggaaagtccgcttgagatcgtaaagatgtttagctcggactagaatatgtagaagtatcgatgtttcgg tggttcgagaaaaaataaaacttagggactgctgtaacacatggactttcttttacaaatcggttgaagacactgtacggcttacccacgtgttt ggatatttgcaggagcccgaagtagtcgatctggctcaatttttgatatcgtgtggagctaaaatttgtggcgtcggatcaagtaccttagttatt aagggcgttaaaaaactgcatagcaccgattttacaattattcctgataggatagaggctggaacttttttaattgctgcagcaattactcggtcc tccatttctatgtcaccaattataccgcagcatatgacagctgtgactaataaactccaagagatgggatgtaagctgcgccaaacaagtcaa gacagcctactggtgagtatcaagtcacgtacacttgggtttgtgagaacctttttgtcaaatcttctttgtcgttgttccaatcctcctgttgtgaa gaggctttgaatggaggtacttttggtaccttaacgagcttttgaaattgctgcccttcctctccaattcaaggagcagttattgcaagtcaggat ggaaggattcgcagtttcaaaattagtgccgtactaattatctcttggatccaatttccagttcaatggtatggtgcaaaggaaggagctttgag actctgcccaggagcttgatgatgtgttgtttatgttgcagatcagcccctcgcagttattgtctagtaccagtatcacaactcttccttatcctgg ttttccaaccgacttgcaaccacaattcatgacactcatgaccagttgcatcggacgaagtgttgtaaaagaaaccgtttttgagagtcgtatgc ggcatggtaagccttttgcttttttcaactcgcccgtgcttcataggatggccatgagacaggtttataagcaattcacttgtctggatgcatgac tccctgtgtataatgaagcctaaaggtccttgctttggaatttgaaaggaaagctttggtgatgtgcagtagaagagctgcaaaagttgggag cgaaggtggttgtcaacaaaaacgttgctgtaatacgtggaatagattgtggcaggtaagaacagagtttcttctgtactttgctcctggaatg gacttcgtgcctcttcatgatgtcattgtttctggtgcgaatatgtagtagttaaagaactacaaactgaagtatctgcctccatcattccttcgga acgtagcccttattcagctgttgccctcgcaaccactgaaatgaggacgttccacgattcacagatgaagttgagcatgaagtcgtgcaccat agattgaaaaggcttgccgcctggtgagtcttcctgaatgatattgtagttttttaacgttgcctaatatgtggttgccagttccttgcgtggagtg ccagttactgccacagatttgagagctggagcagctcttgtgcttgctgggttagcagctgatggcactactcacattgagggtatcaaccat attgaccgaggttatgaatcatttgatcaaaagctccgacttcttggagcaagtgttgagagattggcgtccttgcctgtagagctggtgaccc tgtagtttagttttcggaattccagtaaaacagggtgctaggagggctttctcttttaatctgttggtggtgggggcaacgagaaaggtcgggc tcatccacagcggatttgtaactttgagtgcgataggtttgtcagttatttccttgtcacttgtttataatacttcgtacggtctcattctttatgatggt cgattttttcaaggaaaaaattaaagatttctttcctgtttcc SEQ ID NO: 2 – The nucleotide sequence of Marchantia polymorpha MurA coding sequence: atgatgcgcgctcagatgacttcagcgtcctcctgctggcctgtacgaaattcgagcattccgggcttggtagctcacaatctttctccccctc aggtccctggagttcaaagtgacaatggtgtgtttggaagcaggacggggctactcgtcgaatgcctcgaagtctcgggtgggagcaaact ttctggccatgtcggaataagtggagccaagaattcggcgttggctgttttggctggagctctatgttcagaagaggagctgaatttgaaaatg atacccgacttgcatgacattcaaaggatggttcaggttcttcaatctgtaggggtgaaagtgaagcgttctgcctctggtctcacagtcgacg cgagcgaaattgtctcagtagagccttgtccggaagtagttaggaaattaagagctagttttttcgtcattggagctttagtaggacggaaggg cgaagccgtcgttcccctccccggaggatgcgacataggagctcggcccatcgatcttcacgtgcgtggactgcgagctctgggtgccca ggtggagataaggcaagacaaggtttatgcacgtgcatctcatggtaagagattagtagggggcaaatttcatcttgattatccaagtgttgg cgccactgaaaccctcatgatggctgcctctttggcagacggagaaaccgtactgtcaaatgtggctcaggagcccgaagtagtcgatctg gctcaatttttgatatcgtgtggagctaaaatttgtggcgtcggatcaagtaccttagttattaagggcgttaaaaaactgcatagcaccgatttt acaattattcctgataggatagaggctggaacttttttaattgctgcagcaattactcggtcctccatttctatgtcaccaattataccgcagcatat gacagctgtgactaataaactccaagagatgggatgtaagctgcgccaaacaagtcaagacagcctactgatcagcccctcgcagttattgt ctagtaccagtatcacaactcttccttatcctggttttccaaccgacttgcaaccacaattcatgacactcatgaccagttgcatcggacgaagt gttgtaaaagaaaccgtttttgagagtcgtatgcggcatgtagaagagctgcaaaagttgggagcgaaggtggttgtcaacaaaaacgttgc tgtaatacgtggaatagattgtggcagttccttgcgtggagtgccagttactgccacagatttgagagctggagcagctcttgtgcttgctggg ttagcagctgatggcactactcacattgagggtatcaaccatattgaccgaggttatgaatcatttgatcaaaagctccgacttcttggagcaa gtgttgagagattggcgtccttgcctgtagagctggtgaccctgtag SEQ ID NO: 3 – The amino acid sequence of Marchantia polymorpha MurA gene: MMRAQMTSASSCWPVRNSSIPGLVAHNLSPPQVPGVQSDNGVFGSRTGLLVECLEVSG GSKLSGHVGISGAKNSALAVLAGALCSEEELNLKMIPDLHDIQRMVQVLQSVGVKVKR SASGLTVDASEIVSVEPCPEVVRKLRASFFVIGALVGRKGEAVVPLPGGCDIGARPIDLH VRGLRALGAQVEIRQDKVYARASHGKRLVGGKFHLDYPSVGATETLMMAASLADGET VLSNVAQEPEVVDLAQFLISCGAKICGVGSSTLVIKGVKKLHSTDFTIIPDRIEAGTFLIAA AITRSSISMSPIIPQHMTAVTNKLQEMGCKLRQTSQDSLLISPSQLLSSTSITTLPYPGFPTD LQPQFMTLMTSCIGRSVVKETVFESRMRHVEELQKLGAKVVVNKNVAVIRGIDCGSSLR GVPVTATDLRAGAALVLAGLAADGTTHIEGINHIDRGYESFDQKLRLLGASVERLASLP VELVTL SEQ ID NO: 4 – The nucleotide sequence of sgRNA3 gatagtcggaaaatcaaccgctatcagccttttagttggc SEQ ID NO: 5 – The nucleotide sequence of MpMurF wild type tgcaccgatagtcggaaaatcaaccgaggg SEQ ID NO: 6 – The nucleotide sequence of MpMurF-1 tgcaccgatgg SEQ ID NO: 7 – The nucleotide sequence of MpMurF-9 tgcccgaggg SEQ ID NO: 8 – The nucleotide sequence of MpMurF-12 tgcaccgatagtcggaaaaccattgccgaggg SEQ ID NO; 9 – The nucleotide sequence of MpMurF-2 tgcaccgatagtcggaaaatcaacgaggg SEQ ID NO: 10 – The nucleotide sequence of MpMurF-7 tgcaccgatagtcggaacggaattcgaggg SEQ ID NO: 11 – The nucleotide sequence of sgRNA4 atagtcggaaaatcaaccgatatcagccttttagttggct SEQ ID NO: 12 - The amino acid sequence of MpMurF wild type CTGSRKINRG SEQ ID NO: 13 – The amino acid sequence of MpMurF-1 CTDGNGFLLL SEQ ID NO: 14 – The amino acid sequence of MpMurF-9 CTEGNGFLLL SEQ ID NO: 15 – The amino acid sequence of MpMurF-12 CTDSRKTIAE SEQ ID NO: 16 – The amino acid sequence of MpMurF-2 CTDSRKINEG SEQ ID NO: 17 – The amino acid sequence of MpMurF-7 CTDSRNGITE SEQ ID NO: 18 – The nucleotide sequence of sgRNA2 agcaaactttctggccatgttcgtttgaaagaccggtaca SEQ ID NO: 19 – The nucleotide sequence of sgRNA1 tttcgtacaggccagcaggaaagcatgtccggtcgtcc SEQ ID NO: 20 – The nucleotide sequence of MpMurA wild type agcaaactttctggccatgtcggaataagt SEQ ID NO: 21 – The nucleotide sequence of MpMurA-10 agcaaactttctgtcggaataagt SEQ ID NO: 22 – The nucleotide sequence of MpMurA-13 agcaaactttctgtcggaataagt SEQ ID NO: 23 – The nucleotide sequence of MpMurA-17 agcaaactttctggccaagaactttctgtcggaataagt SEQ ID NO: 24 – The nucleotide sequence of MpMurA wild type cgtcctcctgctggcctgtacgaaattcg SEQ ID NO: 25 – The nucleotide sequence of MpMurA-8 gcgtcctgtacgaaattcg SEQ ID NO: 26 – The nucleotide sequence of MpMurA-15 gcgtcctcctacgaaattcg SEQ ID NO: 27 – The nucleotide sequence of MpMurA-23 gcgtcctcctggcctgtacgaaattcg SEQ ID NO: 28 - The amino acid sequence of MpMurA wild type SKLSGHVGIS SEQ ID NO: 29 – The amino acid sequence of MpMurA-10 SKLSVGIS SEQ ID NO: 30 – The amino acid sequence of MpMurA-13 SKLSVGIS SEQ ID NO: 31 – The amino acid sequence of MpMurA-17 SKLSGQELSVGIS SEQ ID NO: 32 – The amino acid sequence of wild type MpMurA ASSCWPVRNS SEQ ID NO: 33 – The amino acid sequence of MpMurA-8 ASCTKF SEQ ID NO: 34 – The amino acid sequence of MpMurA-15 ASSYEI SEQ ID NO: 35 – The amino acid sequence of MpMurA-23 ASSWPVRNS Detailed Description of the Invention The present invention will be described with respect to particular embodiments and with reference to certain drawings but the disclosure is not limited thereto but only by the claims. Any reference signs in the claims shall not be construed as limiting the scope. Of course, it is to be understood that not necessarily all aspects of advantages may be achieved in accordance with any particular embodiment. Thus, for example those skilled in the art will recognise that the disclosed embodiments may be embodied or carried out in a manner that achieves or optimises one advantage or group of advantages as taught herein without necessarily achieving other aspects or advantages as may be taught or suggested herein. The disclosure together with features and advantages thereof, may best be understood by reference to the following detailed description when read in conjunction with the accompanying drawings. The aspects and advantages of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter. Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one disclosed embodiment. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may do so. Similarly, it should be appreciated that in the description of exemplary disclosed embodiments, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. It should be appreciated that “embodiments” of the disclosure can be specifically combined together unless the context indicates otherwise. The specific combinations of all disclosed embodiments (unless implied otherwise by the context) are further disclosed embodiments of the claimed invention. In addition, as used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used herein, the term “comprising” means “including”. Variations of the word “comprising”, such as “comprise” and “comprises” have correspondingly varied meanings. For example, a composition “comprising” material A may consist exclusively of material A, or may include material A and any other number of other additional component / s (e.g. material B, and / or material C). Glyphosate-sensitive bryophyte Provided herein is a glyphosate-sensitive bryophyte, wherein the bryophyte has: (a) reduced expression of the gene encoding UDP-N-acetylglucosamine enolpyruvyl transferase (MurA); and / or (b) reduced MurA activity; relative to a corresponding wild-type glyphosate- tolerant bryophyte. In some embodiments, the MurA gene is an endogenous MurA gene. In some embodiments, there is a glyphosate-sensitive bryophyte, wherein said bryophyte comprises one or more mutations in the MurA gene, optionally wherein said mutation is a loss-of-function mutation. In some embodiments, the MurA gene is an endogenous MurA gene. Bryophytes are a group of land plants, sometimes treated as a taxonomic division, that contains three groups of non-vascular land plants: the liverworts, hornworts, and mosses. In some embodiments, the bryophyte is a liverwort (Marchantiophyta). In some embodiments, the bryophyte is a hornwort. In other embodiments, the bryophyte is a moss. In some embodiments, the bryophyte is of the genus Marchantia, Lunaria or Physcomitrium. Bryophytes are an example of a non-vascular plant. As used herein, the term “non- vascular plant” refers to a plant lacking a vascular system (i.e. a xylem and phloem). “Non- vascular plants” will be understood herein to encompass whole non- vascular plants, component / s of whole non-vascular plants, spores of whole non-vascular plants, and whole non- vascular plant sporelings. Non-limiting examples of non-vascular plants include bryophytes such as mosses, liverworts and hornworts. The bryophyte may be of the genus Marchantia. Marchantia is a genus of liverworts in the family Marchantiaceae and the order Marchantiales. In some embodiments, said glyphosate- sensitive bryophyte is selected from the group consisting of Marchantia alpestris, Marchantia aquatica, Marchantia berteroana, Marchantia carrii, Marchantia chenopoda, Marchantia debilis, Marchantia domingenis, Marchantia emarginata, Marchantia foliacia, Marchantia grossibarba, Marchantia inflexa, Marchantia linearis, Marchantia macropora, Marchantia novoguineensis, Marchantia paleacea, Marchantia palmata, Marchantia papillate, Marchantia pappeana, Marchantia polymorpha, Marchantia quadrata, Marchantia rubribarba, Marchantia solomonensis, Marchantia streimannii, Marchantia subgeminata, Marchantia vitiensis, Marchantia wallisii, or Marchantia nepalensis. In some embodiments, said glyphosate-sensitive bryophyte is Marchantia polymorpha. In some embodiments, the bryophyte belongs to the genus Lunularia. The bryophyte may be Lunularia cruciata. In some embodiments, the bryophyte belongs to the genus Physcomitrium. The bryophyte may be Physcomitrium patens. In some embodiments, the glyphosate-sensitive bryophyte comprises one or more mutations (e.g. a loss-of-function or inactivating mutation(s)) in the MurA gene. In some embodiments, the loss-of-function or inactivating mutation comprises one or more deletions, insertions or substitutions. In some embodiments the mutation may be the deletion of one or more glycine amino acids. In some embodiments, the mutations may be the deletion of one or more histidine amino acids. In some embodiments, the mutation may be the deletion of one or more glycine and histidine amino acids. In some embodiments, the mutation may be the substitution of histidine for glycine. In some embodiments, the mutation may be the insertion of glutamic acid. In some embodiments, the mutation may be the insertion of leucine. In some embodiments, the mutation may be the insertion of serine. In some embodiments, the mutation may be the insertion of glutamic acid, leucine and / or serine. In some embodiments, the mutation may be the substitution of histidine for glycine and the insertion of glutamic acid, leucine and / or serine. In some embodiments, the mutation may be the deletion of one or more cysteine amino acids. In some embodiments, the glyphosate-sensitive bryophyte comprises one or more of the mutations present within SEQ ID NOs: 20-23, or 25-27. In some embodiments, the mutation may be the insertion of a sequence of 9 nucleotides in length between position 796 and 797 of SEQ ID NO: 1. In some embodiments, the nucleotide insertion results in a sequence comprising SEQ ID NO: 23. In some embodiments, the nucleotide insertion results in a His65→Gln65 substitution, and the insertion of Glu66, Leu67 and Ser68 to SEQ ID NO: 3. In some embodiments, the mutation may be the deletion of nucleotide positions 790-796 of SEQ ID NO: 1. In some embodiments, the nucleotide deletion results in a sequence comprising SEQ ID NO: 21. In some embodiments, the nucleotide deletion results in a sequence comprising SEQ ID NO: 22. In some embodiments, the nucleotide deletion results in the deletion of amino acids Gly64 and His65 of SEQ ID NO: 3. In some embodiments, the mutation may be the deletion of nucleotide positions 635-645 of SEQ ID NO: 1. In some embodiments, the nucleotide insertion results in a sequence comprising SEQ ID NO: 26. In some embodiments, the nucleotide deletion results in frameshift after Ser11, and a premature stop codon at amino acid position 15 of SEQ ID NO: 3. In some embodiments, the mutation may be a deletion of nucleotide positions 633-644 of SEQ ID NO: 1. In some embodiments, the nucleotide insertion results in a sequence comprising SEQ ID NO: 25. In some embodiments, the nucleotide deletion may result in frameshift after Ser10 of SEQ ID NO: 3 and premature stop codon 24 aa downstream. In some embodiments, the mutation may be a deletion of position 635-638 of SEQ ID NO: 1. In some embodiments, the nucleotide insertion results in a sequence comprising SEQ ID NO: 27. In some embodiments, the nucleotide deletion results in the deletion of Cys12 of SEQ ID NO: 3. In some embodiments, the MurA gene is an endogenous MurA gene. The term “glyphosate-sensitive bryophyte” refers to a bryophyte which is affected negatively by treatment with glyphosate, wherein the treatment may result in, but is not limited to, reduced growth or death. In some embodiments, the term “glyphosate-sensitive bryophyte” refers to a bryophyte that is unable to grow on more than 5 μM of glyphosate. In some embodiments, the term “glyphosate-sensitive bryophyte” refers to a bryophyte that is unable to grow on a substrate comprising glyphosate at a concentration equal to, or greater than, 5 µM, or 4.5 µM, or 4 µM, or 3.5 µM, or 3 µM, or 2.5 µM, or 2 µM, or 1.5 µM, or 1 µM, 0.5 µM or 0.1 µM of glyphosate. In some embodiments, the term “glyphosate-sensitive bryophyte” refers to a bryophyte that is unable to grow on a substrate comprising glyphosate at a concentration equal to, or greater than 5-10 µM. The term “wild-type” refers to a corresponding bryophyte that is isolated from a naturally-occurring source. A wild-type bryophyte is that which is most frequently observed in a population and is thus arbitrarily designed the “normal” or “wild-type” form of the bryophyte. In contrast, the term “modified”, “mutant” or “variant” refers to a bryophyte that comprises modifications in the sequences of its genes (e.g., substitutions, truncations, or insertions), post- translational modifications and / or functional properties (e.g., altered characteristics) when compared to the wild-type gene or gene product. In some embodiments, a wild-type bryophyte is a bryophyte that is glyphosate-tolerant and / or that has not been genetically modified. In some embodiments, the term “glyphosate-tolerant bryophyte” refers to a bryophyte that can grow on a substrate comprising glyphosate at a concentration equal to, or greater than 5µM of glyphosate. In some embodiments, the term “glyphosate-tolerant bryophyte” refers to a bryophyte that can grow on a substrate comprising glyphosate at a concentration equal to, or greater than 4-6 µM of glyphosate. In some embodiments, the term “glyphosate-tolerant bryophyte” refers to a bryophyte that can grow on a substrate comprising glyphosate at a concentration equal to, or greater than 3-7 µM of glyphosate. Provided herein is a glyphosate-sensitive bryophyte, wherein the bryophyte has: (a) reduced expression of the gene encoding UDP-N-acetylglucosamine enolpyruvyl transferase (MurA); and / or (b) reduced MurA activity; relative to a corresponding wild-type glyphosate- tolerant bryophyte “Reduced expression” may refer to 50%, 60%, 70%, 80%, 90%, 95%, 99% or 100% reduction in the expression of the MurA gene, e.g. relative to a corresponding wild-type glyphosate-tolerant bryophyte. In some embodiments, “reduced expression” may refer to the absence of detectable levels of expression. Similarly, “reduced MurA activity” can refer to at least 50%, 60%, 70%, 80%, 90%, 95%, 99% or 100% reduction in the activity of the MurA enzyme, e.g. relative to a corresponding wild-type glyphosate-tolerant bryophyte. In some embodiments, “reduced MurA activity” may refer to the absence of detectable levels of MurA activity. In some embodiments, “reduced” means “lower”. For example, “reduced expression” may refer to lower expression of the MurA gene, e.g. relative to a corresponding wild-type glyphosate-tolerant bryophyte. Similarly, “reduced MurA activity” may refer to lower activity of the MurA enzyme, e.g. relative to a corresponding wild-type glyphosate-tolerant bryophyte. In some embodiments, MurA activity may be assayed by using shikimate-3-phosphate (S3P) and phosphoenolpyruvate (PEP) as substrates, and detecting the production of EPSP and / or phosphate. For example, the amount of inorganic phosphate produced may be measured. In some embodiments, the amount of EPSP produced may be measured by mass spectrometry, e.g. by liquid chromatography-tandem mass spectrometry (LC-MS / MS). A “loss of function mutation” refers to a genetic lesion that reduces the activity of a gene, either by preventing its expression or by decreasing the activity of the product (e.g. MurA). In some embodiments, loss-of-function refers to reduced activity in comparison to a corresponding wild-type glyphosate-tolerant bryophyte. In some embodiments, loss-of-function refers to at least 50%, 60%, 70%, 80%, 90%, 95%, 99% or 100% reduction in the expression of the gene. In some embodiments, loss-of-function mutation causes at least 50%, 60%, 70%, 80%, 90%, 95%, 99% or 100% reduction in the activity of the MurA enzyme, e.g. relative to a corresponding wild-type MurA enzyme. In some embodiments, loss-of-function refers to no activity in comparison to a corresponding wild-type glyphosate-tolerant bryophyte. In some embodiments, the loss-of-function mutation is in the promoter. In some embodiments, the loss of function mutation is in the exon. Reduced expression of the gene encoding UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) may involve gene knockdown or gene knockout. Reduced expression can encompass reduced transcription of the MurA gene and / or reduced translation of the corresponding mRNA. It can be achieved by a variety of means available to the skilled person, such as RNAi, CRISPR, TALENs, siRNA, or shRNA. Reduced activity of MurA can also be achieved by a variety of means available to the skilled person, such as RNAi, CRISPR, siRNA, or shRNA. In some embodiments, the MurA gene may comprise, or consist of, a sequence having at least 70%, 75%, 80%, 85%, 90%, 95% or 99% sequence identity to SEQ ID NO: 1. In some embodiments, the MurA gene comprises SEQ ID NO: 1. In some embodiments, the MurA gene consists of SEQ ID NO: 1. In some embodiments, the MurA gene encodes a sequence having at least 70%, 75%, 80%, 85%, 90%, 95% or 99% sequence identity to SEQ ID NO: 3. In some embodiments, the MurA gene encodes SEQ ID NO: 3. In some instances, the bryophyte is not exclusively obtained by essentially biological process for the production of plants (e.g. involving steps of sexual crossing and selection). Methods of generating a glyphosate-sensitive bryophyte Provided herein is a method of generating the glyphosate-sensitive bryophyte of the invention, wherein the method comprises targeted mutagenesis. The term “targeted mutagenesis” refers to a technique that induces specific mutation(s) in targeted locations of the genome. In some embodiments, there is a method of generating the glyphosate-sensitive bryophyte according to the invention, wherein the method comprises targeted mutagenesis. In some embodiments, targeted mutagenesis may involve, but is not limited to, CRISPR mutagenesis. In some embodiments, CRISPR mutagenesis involves a CRISPR endonuclease and a guide RNA (gRNA), wherein said gRNA is targeted to the MurA gene. In some embodiments, the CRISPR endonuclease is Cas9. In some embodiments, the gRNA comprises a sequence that is complementary to a PAM sequence. The use of “genetic modification” refers to the manipulation of an organism’s genes by introducing, eliminating or rearranging specific genes using the methods of modern molecular biology. In some embodiments, the methods of the invention do not comprise an essentially biological process for the production of plants. For example, in some embodiments, the methods of the invention do not comprise steps of sexual crossing and selection. Vectors Provided herein is a vector comprising a guide RNA (gRNA), wherein said gRNA is targeted to the MurA gene. In some embodiments, the gRNA comprises or consists of a sequence having at least 90%, 95%, or 98% sequence identity to any one of SEQ ID NOs: 4, 11, 18 or 19. In some embodiments, the gRNA comprises or consists of any one of SEQ ID NOs: 4, 11, 18, or 19. The aforementioned “sequence identity” may be expressed as a percentage in relation to the full-length sequence of SEQ ID NOs: 4, 11, 18, or 19. In some embodiments, the vector further comprises a polynucleotide encoding a CRISPR endonuclease, optionally wherein said CRISPR endonuclease is Cas9. In some embodiments, the vector may be in the form of a plasmid, a viral vector, or a bacteriophage. In some embodiments, the vector may be for use in the method of generating the glyphosate-sensitive bryophyte of the invention. For example, the vector may be configured for, adapted for, and / or suitable for use in the method of generating the glyphosate-sensitive bryophyte of the invention. In some embodiments, the vector comprises, or consists of, a polynucleotide sequence having at least 70%, 75%, 80%, 85%, 90%, 95% or 99% sequence identity to SEQ ID NOs 4, 11, 18 or 19. The aforementioned “sequence identity” may be expressed as a percentage in relation to the full- length sequence of SEQ ID NOs 4, 11, 18 or 19. In some embodiments, the vector(s) are introduced by means of transformation, e.g. using Agrobacterium. In some embodiments, the vectors are introduced by using electroporation. In some embodiments, the vector(s) are introduced into bryophyte sporelings, e.g. into Marchantia polymorpha sporelings. Transformation methods include the use of liposomes, electroporation, heat shock, floral dip, chemicals that increase free DNA uptake, injection of the DNA directly into the plant, particle gun bombardment, agrobacterium mediate transformation, transformation using viruses or pollen, or microprojection. Methods may be selected from the calcium / polyethylene glycol method for protoplasts, electroporation of protoplasts, microinjection into plant material, DNA or RNA-coated particle bombardment, infection with (non-integrative) viruses and the like. Methods for coating DNA or RNA onto microparticles are well known to those of ordinary skill in the art for example the methods described in Ismagul et al BMC Plant Biology 201818: 135, or Kikkert JR. Cell biology: a laboratory handbook, vol.4. San Diego: Academic Press; 1998. p.157–61, or Sanford JC, et al. Methods Enzymol.1993 217:483–509. Accordingly, suitable microparticles complexed with the polynucleotide and / or the vector of the composition are known to the skilled person. Methods of the invention that comprise modifying heritable genetic material of a plant may comprise transforming the plant, preferably wherein the transforming comprises Agrobacterium mediated transformation. Transgenic plants, including transgenic crop plants, are preferably produced via Agrobacterium tumefaciens mediated transformation. Uses of glyphosate-sensitive bryophytes and methods of screening candidate compounds for EPSPS inhibitors Provided herein is the use of the glyphosate-sensitive bryophyte according to the invention for identifying EPSPS inhibitors. Provided herein is also a method of screening candidate compounds for EPSPS inhibitor activity, the method comprising the steps of: (i) applying one or more different candidate compounds to the glyphosate-sensitive bryophyte of the invention; and (ii) determining the phenotypic response of the glyphosate-sensitive bryophyte, optionally wherein the phenotypic response is reduced growth or death. In some embodiments, the method may involve a further step (iii) which comprises applying the one of more candidate compounds to a control bryophyte and determining the phenotypic response, optionally wherein the phenotypic response is survival of the control bryophyte. In some embodiments, the control bryophyte is a positive control. Compounds with known herbicidal activity may be used in the methods of the present invention as a positive control. Such compounds may include commercial herbicides used at concentrations known to cause mode of action specific symptoms. Examples of such compounds include: clodinafop-propargyl, cyhalofop-butyl, diclofop-methyl, fenoxaprop-P- ethyl, fluazifop-P-butyl, haloxyfop-R-methyl, propaquizafop, quizalofop-P-ethyl, alloxydim, butroxydim, clethodim, cycloxydim, profoxydim, sethoxydim, tepraloxydin, tralkoxydim, pinoxaden, amidosulfuron, azimsulfuron, bensulfuron-methyl, chlorimuron-ethyl, chlorsulfuron, cinosulfuron, cyclosulfamuron, ethametsulfuron-methyl, ethoxysulfuron, flazasulfuron, flupyrsulfuron-methyl- Na, foramsulfuron, halosulfuron-methyl, imazosulfuron, iodosulfuron, mesosulfuron, metsulfuron-methyl, nicosulfuron, oxasulfuron, rimisulfuron-methyl, prosulfuron, pyrazosulfuron-ethyl, rimsulfuron, sulfometuron-methyl, sulfosulfuron, thifensulfuron-methyl, triasulfuron, tribenuron-methyl, trifloxysulfuron, triflusulfuron-methyl, tritosulfuron, imazapic, imazamethabenz-methyl, imazamox, imazapyr, imazaquin, imazethapyr, cloransulam-methyl, diclosulam, florasulam, flumetsulam, metosulam, penoxsulam, bispyribac-Na, pyribenzoxim, pyriftalid, pyrithiobac-Na, pyriminobac-methyl, flucarbazone-Na, propoxycarbazone-Na, benfluralin, butralin, dinitramine, ethalfluralin, oryzalin, pendimethalin, trifluralin, amiprophos- methyl, butamiphos, dithiopyr, thiazopyr, propyzamide = pronamide, tebutam, chlorthal- dimethyl, clomeprop, 2,4-D, 2,4-DB, 2,4-DP, MCPA, MCPB, mecoprop, chloramben, dicamba, TBA, clopyralid, fluroxypyr, picloram, triclopyr, carboxylic acid quinclorac, quinmerac, benazolin- ethyl, ametrine, atrazine, cyanazine, desmetryne, dimethametryne, prometon, prometryne, propazine, simazine, simetryne, terbumeton, terbuthylazine, terbutryne, trietazine, hexazinone, metamitron, metribuzin, amicarbazone, bromacil, lenacil, terbacil, chloridazon, desmedipham, phenmedipham, bromofenoxim, bromoxynil, ioxynil, bentazon, pyridate, pyridafol,chlorobromuron, chlorotoluron, chloroxuron, dimefuron, diuron, ethidimuron, fenuron, fluometuron, isoproturon, isouron, linuron, methabenzthiazuron, metobromuron, metoxuron, monolinuron, neburon, siduron, tebuthiuron, propanil, pentanochlor, butylate, cycloate, is dimepiperate, EPTC, esprocarb, molinate, orbencarb, pebulate, prosulfocarb, benthiocarb,tiocarbazil, triallate,, vemolate, bensulide, benfuresate, ethofumesate, glyphosate, sulfosate, glufosinate-ammonium, bilanaphos, amitrole, norflurazon, diflufenican, picolinafen, beflubutamid, fluridone, flurochloridone, flurtamone, clomazone, acifluorfen-Na, bifenox, chlomethoxyfen, fluoroglycofen-ethyl, fomesafen, halosafen, lactofen, oxyfluorfen, fluazolate, pyraflufen-ethyl, cinidon-ethyl, flumioxazin, flumiclorac-pentyl, fluthiacet-methyl, thidiazimin, oxadiargyl, azafenidin, carfentrazone-ethyl, sulfentrazone, pentoxazone, benzfendizone, butafenacil, pyraclonil, profluazol, flufenpyr-ethyl, acetochlor, alachlor, butachlor, dimethachlor, dimethenamid, metazachlor, metolachlor, pethoxamid, pretilachlor, propachlor, propisochlor, thenylchlor, diphenamid, napropamide, naproanilide, flufenacet, Mefenacet, fentrazamide, anilofos, cafenstrole, piperophos, DSMA, MSMA, asulam, naptalam, diflufenzopyr-Na, Dichlobenil, chiorthiamide, Isoxaben, flupoxam, diquat, paraquat, chlorpropham, propham, carbetamide, Dinitrophenol DNOC, dinoseb, dinoterb, Flamprop-M-methyl / -isopropyl, quinclorac, TCA, dalapon, flupropanate, difenzoquat, mesotrione, sulcotrione, isoxachlortole, isoxaflutole, benzofenap, pyrazolynate, pyrazoxyfen, Benzobicyclon, bromobutide, (chloro)- flurenol, cinmethylin, cumyluron, dazomet, daimuron, etobenzanid, fosamine, indanofan, metam, oxaziclomefone, oleic acid, pelargonic acid, pyributicarb. In some embodiments, the control bryophyte is a negative control. In some embodiments, the negative control samples are not contacted with a known herbicide or plant growth inhibitor. In some embodiments, the control bryophyte is a wild-type glyphosate-tolerant bryophyte. The term “inhibitor” refers to an agent that slows or interferes with a chemical action. In some embodiments, the inhibitor is an exogenous inhibitor, e.g. it is applied exogenously to the glyphosate-sensitive bryophyte. In some embodiments, the inhibitor is a small molecule. A small molecule may be an organic compound having a low molecular weight (e.g. ≤ 1000 Da). In some embodiments, the small molecule is hydrophobic. In some embodiments, the inhibitor is a herbicide, e.g. a broad-spectrum herbicide. The term “herbicide” refers to a compound that is toxic to plants and results in inhibited growth or death of unwanted vegetation. In some embodiments, the inhibitor may be analysed by mass spectrometry, e.g. by liquid chromatography-tandem mass spectrometry (LC-MS / MS). In some embodiments, the inhibitor is analysed using hydrophilic interaction liquid chromatography (HILIC) coupled to mass spectrometry (e.g. in the negative ion mode). The term “phenotypic response” refers to the ability of an organism to change in response to stimuli or inputs from the environment. In some embodiments, the phenotypic response is survival, reduced growth, or death. Use of MurA gene for providing resistance against EPSPS inhibitors Provided herein is a use of the MurA gene for providing resistance against EPSPS inhibitors. For example, said MurA gene can be introduced into a plant, e.g. by transformation, in order to provide resistance against one or more EPSPS inhibitors. Said plant may be an angiosperm, and / or one of the monocot or dicot plants described in the “Transgenic plants” section provided below. In some embodiments, said use comprises heterologous expression of MurA. In some embodiments, the MurA gene could provide resistance in the transformed plant (i.e. transgenic plant) against glyphosate. In some embodiments, said MurA gene comprises or consists of a sequence having at least 70%, 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, or 98% sequence identity to SEQ ID NO: 1, optionally wherein said MurA gene comprises or consists of SEQ ID NO: 1. The aforementioned amount of “sequence identity” when used in connection with the MurA gene sequence may be expressed as a percentage in relation to the full-length polynucleotide / polypeptide of the invention. Sequence identity As used herein, “sequence identity” refers to the percentage of residues that are identical in the same positions in the sequences being analysed. As used herein “sequence similarity” refers to the percentage of residues that have similar biophysical / biochemical characteristics in the same positions (e.g. charge, size, hydrophobicity) in the sequences being analysed. Methods of alignment of sequences for comparison are well-known in the art, including manual alignment and computer assisted sequence alignment and analysis. This latter approach is a preferred approach, due to the increased throughput afforded by computer assisted methods. As noted below, a variety of computer programs for performing sequence alignment are available, or can be produced by one of skill in the art. The determination of percentage sequence identity and / or similarity between any two sequences can be accomplished using a mathematical algorithm. Examples of such mathematical algorithms are the algorithm of Myers and Miller, CABIOS 4:11-17 (1988); the local homology algorithm of Smith et al., Adv. Appl. Math.2:482 (1981); the homology alignment algorithm of Needleman and Wunsch, J. Mol. Biol.48:443-453 (1970); the search-for- similarity-method of Pearson and Lipman, Proc. Natl. Acad. Sci.85:2444-2448 (1988); the algorithm of Karlin and Altschul, Proc. Natl. Acad. Sci. USA 87:2264-2268 (1990), modified as in Karlin and Altschul, Proc. Natl. Acad. Sci. USA 90:5873-5877 (1993). Computer implementations of these mathematical algorithms can be utilized for comparison of sequences to determine sequence identity and / or similarity. Such implementations include, for example: CLUSTAL in the PC / Gene program (available from Intelligenetics, Mountain View, Calif); the AlignX program, versionl0.3.0 (Invitrogen, Carlsbad, CA) and GAP, BESTFIT, BLAST, PASTA, and TFASTA in the Wisconsin Genetics Software Package, Version 8 (available from Genetics Computer Group (GCG), 575 Science Drive, Madison, Wis., USA). Alignments using these programs can be performed using the default parameters. The CLUSTAL program is well described by Higgins et al. Gene 73:237-244 (1988); Higgins et al. CABIOS 5:151-153 (1989); Corpet et al. Nucleic Acids Res.16:10881-90 (1988); Huang et al. CABIOS 8:155-65 (1992); and Pearson et al., Meth. Mol. Biol.24:307-331 (1994). The BLAST programs of Altschul et al. J. Mol. Biol.215:403-410 (1990) are based on the algorithm of Karlin and Altschul (1990) supra. Transformation of plants Transformation methods are well known in the art. Thus, according to the various aspects of the invention, a composition and / or polynucleotide of the invention may be introduced into a plant such that the polynucleotide and / or vector is expressed as a transgene. Nucleic acids are introduced into a plant through transformation. The term "introduction" or "transformation" as referred to herein encompasses the transfer of an exogenous polynucleotide into a host cell, irrespective of the method used for transfer. Plant tissue capable of subsequent clonal propagation, whether by organogenesis or embryogenesis, may be transformed with a genetic construct of the present invention and a whole plant regenerated there from. The particular tissue chosen will vary depending on the clonal propagation systems available for, and best suited to, the particular species being transformed. Exemplary tissue targets include leaf disks, pollen, embryos, cotyledons, hypocotyls, megagametophytes, callus tissue, existing meristematic tissue (e.g., apical meristem, axillary buds, and root meristems), and induced meristem tissue (e.g., cotyledon meristem and hypocotyl meristem). The polynucleotide and / or vector may be transiently or stably introduced into a host cell and may be maintained non-integrated, for example, as a plasmid. Alternatively, it may be integrated into the host genome. The resulting transformed plant cell may then be used to regenerate a transformed plant in a manner well known in the art. To select transformed plants, plant material obtained in the transformation is, as a rule, subjected to selective conditions so that transformed plants can be distinguished from untransformed plants. For example, seeds obtained in the above-described manner can be planted and, after an initial growing period, subjected to a suitable selection by spraying. A further possibility is growing the seeds, if appropriate after sterilization, on agar plates using a suitable selection agent so that only the transformed seeds can grow into plants. Alternatively, the transformed plants are screened for the presence of a selectable marker either visually using fluorescent of colour-based reporters, or using molecular techniques to detect the presence of the polynucleotide of the invention. Following DNA transfer and regeneration, putatively transformed plants may also be evaluated, for instance using Southern blot analysis or PCR analysis, for the presence of the gene of interest, copy number and / or genomic organisation. Alternatively, or additionally, expression levels of the newly introduced DNA may be monitored using Northern and / or Western analysis, or by rtPCR or RNA-Seq all such techniques being well known in the art. The generated transformed plants may be propagated by a variety of means, such as by clonal propagation or classical breeding techniques. For example, a first generation (or T1) transformed plant may be selfed and homozygous second-generation (or T2) transformants selected, and the T2 plants may then further be propagated through classical breeding techniques. The generated transformed organisms may take a variety of forms. For example, they may be chimeras of transformed cells and non-transformed cells; clonal transformants (e.g., all cells transformed to contain the expression cassette); grafts of transformed and untransformed tissues (e.g., in plants, a transformed rootstock grafted to an untransformed scion). Methods of the invention that comprise modifying heritable genetic material of a plant may comprise any suitable transformation method known in the art including any process of transformation described herein. In some embodiments, the methods of the invention do not comprise an essentially biological process for the production of plants. For example, in some embodiments, the methods of the invention do not comprise steps of sexual crossing and selection. Transgenic plants Also provided herein is a transgenic plant comprising a transgene. The term “transgenic plant” refers to a plant that has been genetically modified using recombinant DNA technology. The term “transgene” refers to a gene which is artificially introduced into the genome of another organism. In some embodiments, a transgenic plant includes, but is not limited to, transgenic crop plants. In some embodiments, the transgenic plant is generated by means of transformation, e.g. using Agrobacterium. In some embodiments, the transformation uses electroporation or particle bombardment. In some embodiments, the transgenic plant is a non-vascular plant. In some embodiments, the transgenic plant is an angiosperm. The transgenic plant may be a monocot plant and may, for example, be selected from the families Arecaceae, Amaryllidaceae or Poaceae. For example, the plant may be a cereal crop, such as wheat, rice, barley, oat, triticale, rye, buckwheat, or a non- cereal monocot crop such as garlic, onion, leek, yam, oil palm, or banana. The transgenic plant may be a dicot plant and may, for example, be selected from the families Asteraceae, Brassicaceae (e.g. Brassica napus or Arabidopsis thaliana), Chenopodiaceae, Cucurbitaceae, Leguminosae (Caesalpiniaceae, Aesalpiniaceae Mimosaceae, Papilionaceae or Fabaceae), Malvaceae, Rosaceae or Solanaceae. For example, the plant may be selected from lettuce, sunflower, Arabidopsis, broccoli, spinach, water melon, squash, cabbage, tomato, potato, sweet potato, capsicum, tobacco, cotton, okra, apple, rose, strawberry, alfalfa, bean, soybean, field (fava) bean, pea, lentil, peanut, chickpea, apricots, pears, peach, grape vine, bell pepper, chilli, citrus or coffee species. In some embodiments, the transgene comprises MurA. The MurA transgene may comprise, or consist of, a sequence having at least 70%, 75%, 80%, 85%, 90%, 95% or 98% sequence identity to SEQ ID NO: 1. In some embodiments, said MurA gene comprises or consists of SEQ ID NO: 1. In some embodiments, the transgene encodes a functionally active variant. In some embodiments, the transgene encodes a functionally active variant of MurA. In some embodiments, the transgene encodes a fragment. In some embodiments, the transgene encodes a fragment of MurA. In some embodiments, the transgene encodes a truncated form. In some embodiments, the transgene encodes a truncated form of MurA. In some embodiments, the MurA transgene encodes a sequence having at least 70%, 75%, 80%, 85%, 90%, 95% or 99% sequence identity to SEQ ID NO: 3. In some embodiments, the transgene is under the expression of a constitutive promoter. In some embodiments, the transgene is under the expression of an inducible promoter. In some embodiments, the transgene is operably linked to the promoter. in some embodiments, the transgene results in the expression of MurA. In some embodiments, expression of the transgene results in enhanced resistance of the transgenic plant to EPSPS inhibitors. In some instances, the plant, plant part, plant tissue, plant organ, plant cell, plant protoplast, embryo, callus culture, pollen grain or seed is not exclusively obtained by essentially biological process for the production of plants (e.g. involving steps of sexual crossing and selection). Examples The present invention will now be described with reference to specific Examples, which should not be construed as in any way limiting. Example 1 – Bryophytes are glyphosate tolerant To demonstrate that bryophytes are tolerant to glyphosate, the glyphosate sensitivity of three bryophyte species – Marchantia polymorpha, Lunularia cruciata and Physcomitrium patens – was compared with the glyphosate sensitive angiosperm, Arabidopsis thaliana. (Fig 1. A and B). Each of the bryophytes was more tolerant to glyphosate than A. thaliana. Furthermore, growth was minimally affected in both L. cruciata and P. patens across all glyphosate concentrations tested (Fig 1. A and B). To determine the mechanism of said glyphosate tolerance in bryophytes, M. polymorpha was used as an experimental system. Firstly, a glyphosate dose response experiment was conducted, comparing the activities of purified recombinant EPSPS proteins from M. polymorpha and A. thaliana in vitro. The dose response relationship of the EPSPS enzymes from M. polymorpha and A. thaliana to glyphosate was similar (Fig 1. C). The IC50values for glyphosate were 9.60 μM (SE = ± 9.12) for M. polymorpha EPSPS (MpEPSPS) and 14.49 μM (SE = ± 5.98) for A. thaliana EPSPS (AtEPSPS). These values are not significantly different (Welch’s t-test, p > 0.05). The Michaelis-Menten affinity constants (Km) of AtEPSPS and MpEPSPS for the substrate S3P differ slightly with values of 0.1967 mM (SE = ± 0.04463) and 0.1197 mM (SE = ± 0.01282), respectively (Figure 6A and B). The KMvalues for the substrate PEP, with which glyphosate competes with for binding to EPSPS, of MpEPSPS and AtEPSPS were similar at 0.180 mM (SE = ± 0.026) and 0.163 mM (SE = ± 0.034), respectively (Figure 6C and D). Maximum enzyme velocity (Vmax) of AtEPSPS was 3.43-fold higher for PEP and 4.26-fold higher for S3P than MpEPSPS, corresponding to higher catalytic constant (Kcat) and catalytic efficiency (Kcat / Km) of AtEPSPS compared to MpEPSPS (Figure 6E). These differences suggest that AtEPSPS is more tolerant to glyphosate than MpEPSPS. Therefore, differences in M. polymorpha EPSPS enzyme kinetics and sensitivity to glyphosate cannot account for glyphosate tolerance in M. polymorpha. To test if M. polymorpha takes up glyphosate, the quantity of glyphosate in M. polymorpha thalli and A. thaliana leaves (positive control), from plants grown on media supplemented with glyphosate, was measured using LC-MS / MS (Fig 1. D). Glyphosate levels were higher in M. polymorpha than in A. thaliana after 2 days of 5 µM glyphosate treatment. Despite A. thaliana being sensitive to 5 μM glyphosate (Fig.1 A and B), it accumulated roughly 36 times less glyphosate than M. polymorpha. These data demonstrate that glyphosate is taken up by M. polymorpha and indicate that its glyphosate tolerance cannot be explained by low glyphosate uptake. Therefore, an alternative mechanism must confer glyphosate tolerance in M. polymorpha. The inhibition by glyphosate of the EPSPS-catalysed reaction between S3P and PEP blocks the shikimate pathway. It has been reported that S3P accumulates and is rapidly dephosphorylated to shikimate in sensitive, glyphosate-treated plants11-14. To test if shikimate and S3P accumulate following glyphosate treatment in M. polymorpha the quantities of shikimate (Fig 1. E) and S3P (Fig 1. F) were measured in the tissues of A. thaliana (positive control) and M. polymorpha, using LC-MS / MS. In untreated control samples, shikimate levels were higher in M. polymorpha than A. thaliana (Figure 6G). Shikimate ion counts were also measured after plants were grown on media supplemented with 5 μM glyphosate. After 2 days of glyphosate treatment, the fold increase of shikimate was approximately 5 times greater in A. thaliana (77.83-fold) than in M. polymorpha (15.75-fold) compared to untreated plants. A lower accumulation of shikimate therefore correlates with glyphosate tolerance in M. polymorpha (Fig 1. E). S3P also accumulated more in A. thaliana (670.90-fold) than in M. polymorpha (240.16- fold) following glyphosate treatment (Fig 1. F). There were no differences in the quantities of S3P in the tissues of A. thaliana and M. polymorpha in untreated control samples (Figure 6H and I). These data indicate that the greater sensitivity of A. thaliana to glyphosate is correlated with a greater relative increase in S3P and shikimate levels following glyphosate treatment than in M. polymorpha. The increase in shikimate in A. thaliana is likely the result of accumulated S3P being dephosphorylated into shikimate. The accumulation of lower S3P levels on glyphosate treatment in M. polymorpha than in A. thaliana, suggest that this intermediate is being metabolised in the liverwort, but not in the angiosperm. Therefore, it is suggested that the presence of an additional enzyme that metabolises S3P in M. polymorpha but not in A. thaliana. Example 2 – MurA is derived from an EPSPS-like ancestral protein EPSPS and MurA enzymes each transfer the enolpyruvyl moiety from PEP to the substrates S3P and UDP-GlcNAc respectively15-17. Both proteins are encoded in the M. polymorpha genome. By contrast, EPSPS, but not MurA, is encoded in the A. thaliana genome. Therefore, the structural and catalytical similarities between the MurA enzyme in M. polymorpha and EPSPS were investigated to demonstrate that the similarities confer glyphosate tolerance in M. polymorpha. AlphaFold predicts that MpEPSPS and MpMurA proteins are structurally similar, consistent with the hypothesis that MurA and EPSPS are functionally similar (Fig.2 A and B). Each enzyme consists of two domains comprising α-helices and β-sheets joined by a flexible linker region. The cleft between the 2 domains forms the active site of each protein15. The root mean square deviation (RMSD) of atomic positions of the aligned protein structures was 1.347 Å for 146 pruned atom pairs (14.648 Å for all 451 pairs) (Fig.2 C). This indicates a high degree of structural similarity between MpMurA and MpEPSPS. The percentage identity of the amino acid sequences of MpMurA and MpEPSPS was 20.34 % identity, indicating a moderate level of sequence similarity between MpMurA and MpEPSPS. In comparison, the RMSD of the aligned AlphaFold protein structures of M. polymorpha EPSPS and A. thaliana EPSPS was 0.435 Å for 427 pruned atom pairs (0.915 Å for all 439 pairs). The percentage identity of A. thaliana and M. polymorpha EPSPS proteins was higher at 61.61 %. To investigate the evolutionary history of enolpyruvyl transferase enzymes, first EPSPS sequences were identified in bacteria, archaea and Archaeplastida genomes, and MurA sequences were found in bacteria and Archaeplastida, but absent from archaea. Using these sequences, a multiple sequence alignment of 79 enolpyruvyl transferase enzyme sequences was generated. The alignment was used to construct a Maximum Likelihood tree (Figure 7), which is summarised in Fig.2 D. The topology of the tree shows that MurA sequences and many EPSPS sequences share a common ancestor and that extant MurA enzymes evolved from an EPSPS-like ancestor among bacteria. A monophyletic EPSPS clade including bacteria, archaea and Archaeplastida sequences and a monophyletic MurA clade including bacteria and Archaeplastida sequences, together form a well-supported, monophyletic clade that is sister to a polyphyletic clade of bacterial EPSPS enzymes. These data support the suggest that MurA enzymes evolved in bacteria from an EPSPS-like ancestral enzyme. At least one EPSPS was encoded in each of the sampled Archaeplastida genomes. By contrast, 37 of the 51 sampled Archaeplastida genomes encoded a MurA enzyme. While a MurA gene was present in the genomes of all sampled non-angiosperm streptophytes and the only glaucophyte sampled, only 2 of the 6 sampled angiosperms, 3 of the 10 chlorophyte algae, and none of the 3 rhodophyte algae encoded a MurA enzyme (Fig.2 E). To estimate the proportion of angiosperms encoding a MurA gene, a BLASTp search of the 857 angiosperm species included in the 1000 plants (1KP) transcriptomes project8, showed that approximately 20% (178 / 857) of these angiosperms encode a version of MurA. By contrast, almost 100% of the 441 (440 / 441) non-angiosperm streptophytes in that database encode a MurA enzyme. An extensive analysis of angiosperm MurA enzymes can be found in Figure 8. These data suggest that MurA was present in the last common ancestor of the Archaeplastida and has been lost multiple times since. Furthermore, there has been numerous losses of the MurA gene within the angiosperm lineage. However, the high structural similarity of EPSPS and MurA in M. polymorpha and absence of MurA from most glyphosate-sensitive plants is consistent with the involvement of MurA in glyphosate tolerance in M. polymorpha. Example 3 – Marchantia polymorpha MurA confers glyphosate tolerance in M. polymorpha and glyphosate resistance in A. thaliana To functionally test if MpMurA contributes to glyphosate tolerance in M. polymorpha, the expression of MpMurA was genetically manipulated. MpmurA loss-of-function mutants were generated by CRISPR-Cas9 mutagenesis. Six putative MpmurA mutants were isolated, with a variety of genotypes ranging from substitutions of two base pairs to large deletions which are predicted to result in the expression of a truncated version of the MpMurA protein (Figure 9A and B). The glyphosate sensitivity of MpmurA loss-of-function mutants was compared to wild- type plants (Fig 3. A and B). Tak-2 wild type plants are more sensitive to glyphosate than Tak-1 and were therefore used as a conservative baseline for statistical comparison between MpmurA mutants and wild type plants. All MpmurA mutants were more sensitive to glyphosate than Tak- 2 (Fig 3. A; Brown-Forsythe and Welch ANOVA, p < 0.05). However, none of the mutants were more sensitive to the branched-chain amino acid inhibitor chlorsulfuron (Figure 9C), showing the increase in sensitivity was specific to glyphosate. The relative expression of MpMurA in MpmurA mutants was also measured using RT-qPCR. Steady state levels of the MpMurA transcript were lower in MpmurA-23, MpmurA-17, and MpmurA-8 lines than in wild- type (Fig 3. C). While steady state levels of the MpMurA transcript were similar or slightly higher in MpmurA-13, MpmurA-10, and MpmurA-15 lines than wild-type. To conclude, mutants with loss-of-function mutations in the MpMurA gene are more sensitive to glyphosate than wild type plants. To test if increased MpMurA expression confers increased glyphosate tolerance, MpMurA over-expression lines were generated in M. polymorpha and their sensitivity was compared to control plants transformed with an empty vector, and untransformed wild type (Tak-1 or Tak-2) (Fig 3. D and E). The growth of plants overexpressing MpMurA, under the transcriptional control of the CaMV35S promoter (pro35S:MpMurA), on 10 μM glyphosate was greater than untransformed Tak-1 and Tak-2 plants or plants overexpressing YFP (empty vector controls,pro35S:YFP) (Fig 3. D). The area of plants overexpressing MpMurA was also greater at 20 μM of glyphosate, a concentration that almost completely inhibited the growth of the empty vector control (Fig.3 E). The steady state levels of MpMurA mRNA were higher in all lines transformed with thepro35S:MpMurA construct than wild-type controls (Fig 3. F). Therefore, loss of MpMurA function makes M. polymorpha more sensitive to glyphosate than wild type, while MpMurA over-expression increases tolerance. These results are consistent with the hypothesis that MpMurA contributes to glyphosate tolerance in M. polymorpha. To test independently if MpMurA confers glyphosate tolerance, the bryophyte MpMurA gene was expressed in the angiosperm A. thaliana (pro35S:MpMurA). Plants transformed with thepro35S:MpMurA construct were consistently more resistant to glyphosate than the empty vector controls (Fig 3. G and H). Furthermore, the steady state levels of MpMurA mRNA in A. thaliana plants transformed with thepro35S:MpMurA construct correlated with the magnitude of glyphosate resistance conferred. In conclusion, heterologous expression of MpMurA confers glyphosate resistance in A. thaliana. Example 4 - The role of MurA in glyphosate tolerance in M. polymorpha is independent of its function in chloroplasts The target of glyphosate, EPSPS, is chloroplast localised. Disruptions of MurA function causes a macrochloroplast phenotype and defects in chloroplast division18-21. Therefore, it is formally possible that chloroplast defects in M. polymorpha murA loss-of-function mutants confer sensitivity to glyphosate. To test that MurA contributes to glyphosate tolerance in M. polymorpha, independently of its role in regulating chloroplast size and division, MpmurF loss- of-function mutant M. polymorpha plants were generated using CRISPR-Cas9. MurF is an essential enzyme in peptidoglycan biosynthesis, like MurA. It catalyses the formation of UDP- MurNAc-pentapeptide by adding D-alanyl-D-alanine to an acceptor molecule22, 23. Five putative MpmurF loss-of-function mutants were generated using CRISPR (Figure 10A and B). Both MpmurF and MpmurA loss-of-function mutants developed larger and fewer chloroplasts than wild type plants, consistent with the related roles of MpMurF and MpMurA in chloroplast peptidoglycan formation (Fig 4. A-J). If MpmurF mutants and wild type were equally sensitive to glyphosate, and more tolerant than MpmurA mutants, it would suggest that MpMurA confers glyphosate tolerance in M. polymorpha through a mechanism independent from its function in peptidoglycan biosynthesis. The glyphosate sensitivity of MpmurF loss-of-function mutants was not significantly different from Tak-1 and Tak-2 wild type plants (Brown-Forsythe and Welch ANOVA, p > 0.05) (Fig.4 K). Furthermore, the dose response relationship to glyphosate of the two lines MpmurF-2 and MpmurA-12 are indistinguishable from wild type plants and other MpmurF mutants (Figure 10C). These data indicate that MpMurA confers glyphosate tolerance through a mechanism independent from the role in chloroplast peptidoglycan biosynthesis it shares with MpMurF. Example 5 – MpMurA catalyses the same reaction as MpEPSPS It has been shown that putative MpmurA loss-of-function mutants are more sensitive to glyphosate than wild type, and since MpMurA and MpEPSPS are structurally similar. Therefore, the enzymatic activity of purified MpMurA enzyme with S3P and PEP as substrates was measured to determine whether MpMurA confers glyphosate tolerance by catalysing the same reaction as EPSPS – the conversion of shikimate-3-phosphate (S3P) and phosphoenolpyruvate (PEP) to 5-enolpyruvylshikimate-3-phosphate (EPSP) and phosphate (Fig.5). The amount of inorganic phosphate produced by MpMurA incubated with S3P and PEP as substrates was measured24, 25. As controls, the activity of purified MpEPSPS with the same substrates, and the activity of MpMurA with its canonical substrates, UDP-GlcNAc and PEP, were measured (Fig 5. A). Phosphate was produced by MpMurA in the presence of S3P and PEP, which is consistent with MpMurA catalysing the same reaction as EPSPS. The rate of reaction of MpMurA was approximately 100-fold less than that of EPSPS. The reaction rate of MpMurA-catalysed reaction of S3P and PEP was approximately 8-fold higher than MpMurA with the substrates UDP-GlcNAc and PEP. These data indicate that both MpMurA and MpEPSPS catalyse a reaction between S3P and PEP producing inorganic phosphate. These data are consistent with MpMurA catalysing the transfer of the enolpyruvyl moiety of PEP to both the 3’-hydroxyl of UDP-GlcNAc and S3P. To determine if MpMurA catalyses the production of EPSP from S3P and PEP substrates, liquid chromatography-tandem mass spectrometry (LC-MS / MS) was employed to detect the accumulation of EPSP (Fig 5. B and C). To develop an LC-MS / MS method for the quantification of EPSP, the reaction products of MpEPSPS, incubated with S3P and PEP, were separated using hydrophilic interaction liquid chromatography (HILIC) directly coupled to mass spectrometry in the negative ion mode. A peak at m / z 323.1 was detected, corresponding to the expected m / z value of EPSP. Upon fragmentation (Fig 5. B), fragments at m / z 79 and m / z 97 were observed, characteristic of phosphorylated metabolites. The fragments at m / z 135 and m / z 137 likely correspond to EPSP having lost both the phosphate and the PEP-related structures upon fragmentation. By employing selected reaction monitoring (SRM), EPSP was detected and quantified when MpEPSPS was incubated with S3P and PEP (Fig 5 C). EPSP was detected and quantified when MpMurA was incubated with the same substrates. No EPSP was detected in the negative controls containing the enzyme alone or the substrates alone (chromatographs depicting the peaks corresponding to the substrates S3P and PEP can be found in Figure 11). The quantity of EPSP produced per mg of enzyme, measure in ion counts, was approximately 5,500-fold less for MpMurA (1.24x106ion counts / mg enzyme) than measured for MpEPSPS (6.82x109ion counts / mg enzyme) (Fig 5 D). This indicates that MpMurA catalyses the reaction of S3P and PEP to form EPSP, although it is catalytically less active than MpEPSPS. Accumulation of EPSP product when MpMurA is incubated with S3P and PEP substrates demonstrates that MpMurA can catalyse the same reaction as MpEPSPS. Glyphosate inhibits EPSPS activity by competing with PEP substrate for binding to the enzyme16,26. To test if MpMurA was inhibited by glyphosate, the amount of EPSP produced by MpMurA was measured at 8 concentrations of glyphosate using LC-MS / MS (Fig 5. E). The quantity of EPSP produced by MpEPSPS positive control enzyme decreased with increasing concentrations of glyphosate, consistent with the known inhibition of the forward reaction by the herbicide. The quantity of EPSP produced by MpMurA was also reduced by glyphosate, following a similar dose-response relationship as MpEPSPS. However, MpMurA was slightly more sensitive to glyphosate than MpEPSPS (Fig 5. F). 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Claims

CLAIMS 1. A glyphosate-sensitive bryophyte, wherein said bryophyte has: (a) reduced expression of the gene encoding UDP-N-acetylglucosamine enolpyruvyl transferase (MurA); and / or (b) reduced MurA activity; relative to a corresponding wild-type glyphosate-tolerant bryophyte.

2. The bryophyte of claim 1, wherein the glyphosate-sensitive bryophyte is of the genus Marchantia, preferably Marchantia polymorpha.

3. The bryophyte of claim 1 or claim 2, wherein the bryophyte comprises one or more mutations in the MurA gene, optionally wherein said mutation is a loss-of-function mutation.

4. A method of generating the glyphosate-sensitive bryophyte according to any one of claims 1- 3, wherein the method comprises targeted mutagenesis.

5. The method of claim 4, wherein the targeted mutagenesis is CRISPR mutagenesis.

6. A vector comprising a guide RNA (gRNA), wherein said gRNA is targeted to the MurA gene.

7. The vector of claim 6, wherein, wherein the gRNA comprises or consists of a sequence having at least 90%, 95%, or 98% sequence identity to any one of SEQ ID NOs: 4, 11, 18 or 19, optionally where the gRNA comprises or consists of any one of SEQ ID NOs: 4, 11, 18, or 19.

8. The vector of claim 6 or claim 7, wherein the vector further comprises a polynucleotide encoding a CRISPR endonuclease, optionally wherein said CRISPR endonuclease is Cas9.

9. Use of the bryophyte according to any one of claims 1-3 for identifying inhibitors of 5- enolpyruvylshikimate 3-phosphate synthase (EPSPS).

10. A method of screening candidate compounds for EPSPS inhibitor activity, the method comprising the steps of: (i) applying one or more different candidate compounds to the glyphosate-sensitive bryophyte of any one of claims 1-3; and(ii) determining the phenotypic response of the glyphosate-sensitive bryophyte, optionally wherein the phenotypic response is reduced growth or death.

11. The method of claim 10, wherein a further step (iii) comprises applying the one of more candidate compounds to a control bryophyte and determining the phenotypic response, optionally wherein the phenotypic response is survival of the control bryophyte.

12. The method of claim 10 or claim 11, wherein the one or more candidate compounds are small molecules.

13. The method of claims 11 or claim 12, wherein the control bryophyte is a wild-type glyphosate-tolerant bryophyte.

14. Use of the MurA gene for providing resistance against EPSPS inhibitors.

15. The use according to claim 14, wherein said MurA gene comprises or consists of a sequence having at least 70%, 75%, 80%, 85%, 90%, 95%, or 98% sequence identity to SEQ ID NO: 1, optionally where the MurA comprises or consists of SEQ ID NO:

1.

16. A transgenic plant comprising a transgene, wherein said transgene comprises MurA.

17. The transgenic plant of claim 16, wherein said MurA gene comprises or consists of a sequence having at least 70%, 75%, 80%, 85%, 90%, 95%, or 98% sequence identity to SEQ ID NO: 1, optionally wherein said MurA gene comprises or consists of SEQ ID NO: 1.

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