A fluorescent molecule for inhibiting strigolactone signal and its synthesis and application

Abstract

The present invention relates to the fields of chemistry and agricultural technology, and more particularly to a fluorescent molecule that inhibits strigolactone signals, its synthesis, and application. The fluorescent molecule that inhibits strigolactone signals has a structural formula as shown in Formula I. The fluorescent molecule that inhibits strigolactone signals of the present invention has a simple structure, is easy to synthesize, and has high biological activity. It can inhibit strigolactone signals and, as a new plant growth regulator, can also be used as a fluorescent molecule in basic botanical research to indicate the transport, distribution, and accumulation of strigolactones. #imgabs0# Formula I.

Description

Technical Field

[0001] The present invention relates to the field of chemistry and agricultural technology, and in particular to a fluorescent molecule capable of inhibiting strigolactone signals, and the synthesis and application thereof. Background Art

[0002] Strigolactones (SLs) are an important class of plant hormones that play a crucial role in regulating plant branching / tillering, parasitic seed germination, and plant-microbe interactions. Furthermore, SLs are widely involved in plant growth and development and environmental responses through interactions with other plant hormones. Therefore, research on the mechanism of action of SLs and the development of SL-based plant growth regulator (PGR) technicals are of great significance. These findings have shown great potential for application in crop genetic improvement, crop architecture regulation, and parasitic weed control. Unfortunately, known SLs and their analogs (including agonists and inhibitors) are difficult to synthesize, have high production costs, and are too few in number to be applied in agricultural production.

[0003] SL fluorescent molecules are compounds modified or engineered from the structure of SLs and their analogs to exhibit both fluorescent signals and SL properties (including agonists and inhibitors). They can be used to visualize the accumulation and distribution of SLs in plants and are important tools for studying SL synthesis, transport, and mechanism of action. Currently, very few fluorescent molecules are ideal for SLs due to the difficulty in achieving both good fluorescent properties and high biological activity. Generally, the introduction of fluorescent scaffolds into strigolactones is achieved primarily through modifications of the A and B rings, with early attempts focusing on the synthesis of aromatic heterocyclic compounds. A variety of SL fluorescent molecules, namely the EGO and ST series probes, have been synthesized using nitrogen derivatives in a highly conjugated manner on the A ring. Some of these probes have demonstrated biological activity in promoting seed germination and fungal hyphal branching in Orobancha seeds, but they do not meet the requirements for real-time in vivo imaging. Several research groups have also reported fluorescent molecules that inhibit SL signals, including an o-benzocyanobenzoic acid derivative and new SL antagonists synthesized by replacing the ether or phenolic ether oxygen of the D ring with a methylene group. These antagonists have shown promise in inhibiting rice tillering or parasitic seed germination, but few highly active inhibitors or fluorescent molecules have been reported. Therefore, the development of new fluorescent molecules that can influence strigolactone signaling is urgently needed.

[0004] Related prior art discloses a strigolactone promoter as a fluorescent probe. This promoter is primarily used to promote root parasitic seed germination, inhibit plant hypocotyl elongation, and inhibit plant branching / tillering. SL inhibitors (which inhibit SL signals) primarily promote plant hypocotyl elongation and branching, significantly increasing crop yields. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a fluorescent molecule that inhibits strigolactone signals.

[0006] The present invention also provides a method for preparing the fluorescent molecule that inhibits strigolactone signals.

[0007] The present invention also proposes the application of the fluorescent molecules for inhibiting strigolactone signals.

[0008] The invention also provides a plant growth regulator.

[0009] The invention also provides a method for regulating plant growth.

[0010] The present invention also provides a fluorescent probe for detecting strigolactones in plants.

[0011] According to one aspect of the present invention, a fluorescent molecule that inhibits strigolactone signals is proposed. The fluorescent molecule that inhibits strigolactone signals has a structural formula as shown in Formula I:

[0012]

[0013] Formula I.

[0014] According to another aspect of the present invention, there is provided a method for preparing the fluorescent molecule for suppressing strigolactone signals, comprising the following steps:

[0015] 5-Hydroxy-3-methylfuran-2(5H)-one and 7-isocyanato-4-methyl-2H-benzopyran-2-one are reacted in the presence of a base to obtain a compound represented by formula I.

[0016] In some embodiments of the present invention, the solvent used in the reaction includes dichloromethane.

[0017] In some embodiments of the present invention, the mass ratio of the 5-hydroxy-3-methylfuran-2(5H)-one, the base and the 7-isocyanate-4-methyl-2H-chromen-2-one is 1:(0.5-1.5):(1-3).

[0018] In some embodiments of the present invention, the reaction temperature is 10-30°C.

[0019] In some embodiments of the present invention, the reaction time is 6 to 18 hours.

[0020] In some embodiments of the present invention, the base comprises an organic base and / or an inorganic base.

[0021] In some embodiments of the present invention, the base comprises at least one of triethylamine, potassium carbonate, sodium carbonate, and cesium carbonate.

[0022] In some embodiments of the present invention, the step of purifying the compound of Formula I is further included, wherein the purification is performed by filtration and recrystallization. The solvent used for recrystallization may be dichloromethane:acetonitrile (v / v) = 2-4:1.

[0023] In some embodiments of the present invention, the preparation method further comprises reacting triphosgene and 7-amino-4-methylcoumarin in the presence of a base to obtain 7-isocyanato-4-methyl-2H-benzopyran-2-one.

[0024] In some preferred embodiments of the present invention, the solvent used in the reaction includes dichloromethane.

[0025] In some preferred embodiments of the present invention, the mass ratio of triphosgene, base and 7-amino-4-methylcoumarin is 1:(1-4):(1-3).

[0026] In some embodiments of the present invention, the reaction temperature is 10-30°C.

[0027] In some embodiments of the present invention, the reaction time is 6 to 18 hours.

[0028] In some embodiments of the present invention, the base comprises an organic base and / or an inorganic base.

[0029] In some embodiments of the present invention, the base comprises at least one of triethylamine, potassium carbonate, sodium carbonate, and cesium carbonate.

[0030] In some embodiments of the present invention, the step of purifying 7-isocyanate-4-methyl-2H-benzopyran-2-one is further included, comprising adding an organic solvent to the obtained 7-isocyanate-4-methyl-2H-benzopyran-2-one, filtering, taking the filtrate, washing with acid, taking the organic phase, rotary evaporating, and recrystallizing to obtain the product.

[0031] Preferably, the organic solvent may be n-hexane: dichloromethane (v / v) = 1:1-4.

[0032] Preferably, the pickling adopts at least one selected from hydrochloric acid, nitric acid and sulfuric acid.

[0033] Preferably, the recrystallization comprises firstly performing a first recrystallization using n-hexane: dichloromethane (v / v) = 1:1-3 and then performing a second recrystallization using dichloromethane: n-hexane (v / v) = 1:1-3.

[0034] According to another aspect of the present invention, there is provided the use of the fluorescent molecule for inhibiting strigolactone signal in any one of the following (1) to (4):

[0035] (1) As a strigolactone inhibitor;

[0036] (2) Regulate plant growth;

[0037] (3) Preparation of fluorescent probes;

[0038] (4) Detection of monocotyledonolactone.

[0039] In some embodiments of the present invention, the concentration of the fluorescent molecule that inhibits the strigolactone signal as a strigolactone inhibitor is >1µM, for example, ≥2µM, 2~200µM, 2~100µM, 2~80µM, 2~60µM, 2~40µM, 2~20µM, 2~10µM, 2~5µM.

[0040] In some embodiments of the present invention, the regulating plant growth comprises promoting the elongation of the hypocotyl of the plant seedling and / or promoting the branch development of the plant. Further, the concentration of the fluorescent molecule that inhibits the strigolactone signal to promote the elongation of the hypocotyl of the plant seedling and / or promote the branch development of the plant is greater than 1µM, for example, ≥2µM, 2-200µM, 2-100µM, 2-80µM, 2-60µM, 2-40µM, 2-20µM, 2-10µM, 2-5µM, ≥10µM, 10-800µM, 10-200µM, 10-100µM, 10-80µM, 10-60µM, 10-40µM, 10-20µM. Furthermore, the concentration of the fluorescent molecule that inhibits the strigolactone signal and promotes the elongation of the hypocotyl of the plant seedling is ≥2µM, for example, 2~100µM, 2~40µM, 2~20µM, 2~10µM, 2~5µM; the concentration of the fluorescent molecule that inhibits the strigolactone signal and promotes the branching development of the hypocotyl of the plant seedling is ≥10µM, for example, 10~800µM, 10~200µM, 10~100µM, 10~80µM, 10~60µM, 10~40µM, 10~20µM.

[0041] In some embodiments of the present invention, the fluorescent molecule that inhibits strigolactone signals regulates plant growth by upregulating the gene expression levels of SMXL6, SMXL7, and SMXL8.

[0042] In some embodiments of the invention, the plant comprises Arabidopsis thaliana.

[0043] According to another aspect of the present invention, a plant growth regulator is provided, wherein the plant growth regulator comprises the above-mentioned fluorescent molecule that inhibits strigolactone signals.

[0044] In some embodiments of the present invention, the plant growth regulator promotes the elongation of the hypocotyl of plant seedlings and / or promotes the branch development of plants. Further, in the plant growth regulator, the concentration of the fluorescent molecule that inhibits the strigolactone signal is greater than 1µM, for example, ≥2µM, 2-200µM, 2-100µM, 2-80µM, 2-60µM, 2-40µM, 2-20µM, 2-10µM, 2-5µM, ≥10µM, 10-800µM, 10-200µM, 10-100µM, 10-80µM, 10-60µM, 10-40µM, 10-20µM.

[0045] In some embodiments of the present invention, the plant growth regulator regulates plant growth by upregulating the gene expression levels of SMXL6, SMXL7 and SMXL8.

[0046] In some embodiments of the invention, the plant comprises Arabidopsis thaliana.

[0047] According to another aspect of the present invention, a method for regulating plant growth is provided, comprising treating the plant with the fluorescent molecule that inhibits strigolactone signaling at a concentration of >1 μM.

[0048] In some embodiments of the present invention, the regulating plant growth comprises promoting the elongation of the hypocotyl of the plant seedling and / or promoting the branch development of the plant. The concentration of the fluorescent molecule that inhibits the strigolactone signal is ≥2µM, for example, 2-200µM, 2-100µM, 2-80µM, 2-60µM, 2-40µM, 2-20µM, 2-10µM, 2-5µM, ≥10µM, 10-800µM, 10-200µM, 10-100µM, 10-80µM, 10-60µM, 10-40µM, 10-20µM. Furthermore, the concentration of the fluorescent molecule that inhibits the strigolactone signal and promotes the elongation of the hypocotyl of the plant seedling is ≥2µM, for example, 2~100µM, 2~40µM, 2~20µM, 2~10µM, 2~5µM; the concentration of the fluorescent molecule that inhibits the strigolactone signal and promotes the branching development of the hypocotyl of the plant seedling is ≥10µM, for example, 10~800µM, 10~200µM, 10~100µM, 10~80µM, 10~60µM, 10~40µM, 10~20µM.

[0049] In some embodiments of the present invention, the fluorescent molecule that inhibits strigolactone signals regulates plant growth by upregulating the gene expression levels of SMXL6, SMXL7, and SMXL8.

[0050] In some embodiments of the invention, the plant comprises Arabidopsis thaliana.

[0051] According to another aspect of the present invention, a fluorescent probe for detecting strigolactones in plants is provided, comprising the above-mentioned fluorescent molecule that inhibits strigolactone signals.

[0052] In some embodiments of the present invention, the detection of strigolactones in plants comprises the following steps: introducing the fluorescent molecules that inhibit strigolactone signals into the plant body.

[0053] In some embodiments of the invention, the plant comprises Arabidopsis thaliana.

[0054] According to some embodiments of the present invention, there are at least the following beneficial effects:

[0055] The fluorescent molecule prepared by the present invention has a simple structure, is easy to synthesize, and has high biological activity. It can be used as a new plant growth regulator to effectively regulate the growth and development of plants. It can also be used as a fluorescent probe in basic botanical research to indicate the transport, distribution, and accumulation of strigolactones.

[0056] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0058] Figure 1 This is the H NMR spectrum of compound SAC in Example 1 of the present invention;

[0059] Figure 2 This is a graph showing the LC-MS test results of compound SAC in Example 1 of the present invention;

[0060] Figure 3 This is the fluorescence confocal result of treating the main root of Arabidopsis seedlings with 5 μM SAC in Example 5 of the present invention. DETAILED DESCRIPTION

[0061] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0062] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed herein are understood to include any and all subranges subsumed therein.

[0063] The terms "preferably," "more preferably," and the like, used herein refer to embodiments of the present invention that may provide certain benefits under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the present invention.

[0064] Unless otherwise specified, "and / or" in the present invention is used to indicate that one or both of the situations described may occur. For example, A and / or B includes (A and B) and (A or B).

[0065] Unless otherwise specified, “about” in the present invention means that the allowable error is within ±20%, further, within ±10%, and further, within ±5%.

[0066] Unless otherwise specified, "room temperature" in the present invention means (25±5)°C.

[0067] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0068] Example 1

[0069] This embodiment provides a fluorescent molecule SAC that suppresses strigolactone signals and a preparation method thereof. Specifically, the preparation route is as follows:

[0070]

[0071] Triphosgene (0.59 g, 2 mmol) was dissolved in 30 mL of dry DCM. 7-Amino-4-methylcoumarin (0.97 g, 5.5 mmol) and triethylamine (1.5 mL) were added with stirring in an ice-water bath. The reaction was allowed to proceed overnight at room temperature. TLC confirmed the complete reaction of the coumarin starting material. 30 mL of n-hexane and 60 mL of DCM were then added to obtain a suspension, which was filtered. The filtrate was washed with 1 M hydrochloric acid solution, and the organic phase was dried over anhydrous sodium sulfate and filtered. The solvent was removed by rotary evaporation, and the resulting solid was dispersed in 15 mL of n-hexane. 20 mL of DCM was added to slurry, and the filtered solid was dissolved in 30 mL of DCM and added dropwise to 50 mL of n-hexane to allow precipitation. The resulting solid was filtered, revealing the intermediate coumarin isocyanate as a white solid, approximately 0.8 g.

[0072] Dissolve 0.1 g of the intermediate obtained above in 15 mL of DCM, add 0.07 g of 5-hydroxy-3-methyl-2(5H)-furanone and 0.05 mL of triethylamine, and allow to react overnight at room temperature. After TLC analysis of the reaction, filter the resulting suspension, and slurry the resulting solid three times with a 3:1 (v / v) ratio of dichloromethane to acetonitrile (20 mL x 3). The resulting solid is the final product, SAC, approximately 62 mg.

[0073] The target product SAC synthesized in Example 1 was identified by H-NMR spectroscopy and liquid chromatography-mass spectrometry. Figure 1-2 As shown, the mass spectrometry detection results showed that it was in positive ion mode, with a molecular weight of 316.1, corresponding to M+H, and the results were consistent with the structure of SAC.

[0074] Furthermore, the present invention investigates the application of SAC as a SL inhibitor, which mainly promotes plant hypocotyl elongation and plant branching.

[0075] Example 2

[0076] This example tests the effect of SAC on the growth of Arabidopsis hypocotyls.

[0077] Prepare 5 mM stock solutions of GR24 (CAS No. 76974-79-3) and SAC: weigh appropriate amounts of GR24 and SAC using a 1 / 10,000 electronic balance, and dissolve GR24 and SAC in 1‰ DMSO (diluted with ultrapure water) to make a fixed volume of 5 mM stock solution.

[0078] Arabidopsis thaliana was cultured in MS medium containing 4.4% MS powder, 3% sucrose, and 0.7% agar, adjusted to a pH of 5.8, and sterilized at high temperature. Before plating, filter-sterilized GR24, SAC, and a blank control (1‰ DMSO, i.e., MOCK) were added to the MS medium to achieve a final concentration of 5 μM for GR24 and 1 μM, 2 μM, 5 μM, and 10 μM for SAC, respectively. The culture was then inoculated. The culture was cultured under low light conditions (16 h light, 8 h dark) at 22°C for 6 days. The hypocotyl length of the Arabidopsis thaliana plants was then measured and statistically analyzed using Digimizer software, and the results were averaged.

[0079] The results are shown in Table 1 below. Compared with the hypocotyl length of the blank control group, the average hypocotyl length was reduced after treatment with GR24. On the contrary, the hypocotyl length was significantly increased by treatment with SAC.

[0080] Table 1 Hypocotyl length after SAC and control treatment (cm)

[0081]

[0082] Example 3

[0083] This example tests the effect of SAC on Arabidopsis branching.

[0084] The Arabidopsis thaliana wild-type Col-0 was used. Seeds were sterilized with 75% ethanol for 15 minutes, rinsed 4-5 times with sterile water, and then vernalized in a 4°C refrigerator for 3 days. Seedlings were then seeded in MS complete medium and cultured for approximately 2 weeks. Seedlings of uniform growth were then transferred to nutrient soil for further cultivation. Cultivation was carried out under strong fluorescent light with a photoperiod of 16 h light / 8 h dark and a temperature of approximately 22°C. Before bolting, 10 μM, 20 μM, 40 μM, 80 μM, and 100 μM SAC in 1‰ DMSO (i.e., MOCK group) solutions were dripped onto axillary buds of Arabidopsis thaliana. Approximately 2 mL per seedling was applied every four days for a total of four applications, with 30 plants per group. The average value was used for the experiment. After bolting, photos were taken, and the number of axillary branches in the rosette was counted. The results are shown in Table 2.

[0085] Table 2 Number of branches after SAC and control group treatment

[0086]

[0087] Example 4

[0088] This example tests the effect of SAC on the expression of SL transcriptional repressor protein.

[0089] In the presence of SL, D14 interacts with corresponding F-box proteins (such as MAX2 in Arabidopsis) through the SKP1-Cullin-F-box complex (SCF), recruiting SL transcriptional repressors (such as SMXL 6, 7, and 8 in Arabidopsis), promoting the expression of SMXL 6, 7, and 8 genes, thereby activating various SL physiological responses. Therefore, this example uses the response of SL to plant phenotypes such as branching and hypocotyl length, as well as signaling-related genes such as SMXL6, 7, and 8, to verify that SAC exerts a series of effects, including regulating hypocotyl length, through the SL signaling pathway. The specific verification steps are as follows:

[0090] Sample processing: Arabidopsis thaliana wild type Columbia ( col ) Seeds were disinfected and vernalized, then planted in MS medium and grown for 8 days under a light condition of 16 hours and darkness of 8 hours (22°C). After 8 days, Arabidopsis seedlings were placed in 1 / 2 MS liquid medium containing 10 μM GR24 and SAC and a blank control for 4 hours. After 4 hours, the Arabidopsis seedlings were removed, the excess reagents were washed off, and the subsequent RT-PCR was performed after drying on filter paper. The experiment was repeated 3 times.

[0091] Total RNA extraction: Trizol method was used to prepare RNAse-free pipette tips, EP tubes and PCR tubes. Mortars were soaked in 0.1% DEPC aqueous solution for 2 days, sterilized at 121°C and autoclaved for 20 min, and dried in a constant temperature drying oven.

[0092] Approximately 100 mg of Arabidopsis seedlings (treated for 4 hours as described above) were placed in a mortar and pestle filled with liquid nitrogen. Grind rapidly until powdered, transfer to 1.5 mL RNase-free EP tubes, add 1 mL of Trizol extract to each tube, mix thoroughly by pipetting, and vortex for 30 seconds. Place on ice for 10 minutes. Add 250 μL of chloroform, vortex thoroughly, and let stand on ice for 5 minutes. Centrifuge at 12,000 rpm at 4°C for 5 minutes. Transfer the supernatant to a fresh pre-chilled EP tube, add 0.6 volumes of pre-chilled isopropanol, mix thoroughly by inversion, and let stand on ice for 10 minutes. Centrifuge at 12,000 rpm at 4°C for 5 minutes, and discard the supernatant. Wash the pellet two to three times with 75% ethanol (resuspend the pellet in 1 mL of 75% ethanol and centrifuge at 12,000 rpm at 4°C for 5 minutes). Discard any excess supernatant. Dry in a laminar flow hood for approximately 10 minutes. Dissolve the RNA in 30-50 μL of RNase-free water. Measure RNA concentration using a microplate reader and assess RNA quality by electrophoresis on a 1% agarose gel. Aliquot 1-2 μg of RNA into tubes and store at -80°C.

[0093] cDNA synthesis: Perform according to the Vazyme HiScript II Strand cDNA Synthesis Kit instructions. Prepare the following system on ice: 1 μg total RNA, 4 μL 4× gDNA wiper mix, 1 μL Oligo dT, 1 μL Random Hexamers, and add Nuclease-Free H2O to 16 μL. Incubate at 42°C for 2 min. Add the following components to the reaction system: 2 μL 10× RT Mix and 2 μL HiScript II Enzyme Mix, and mix thoroughly. Synthesize cDNA by annealing at 25°C for 5 min, extending at 50°C for 15 min, and inactivating at 85°C for 2 min. Aliquot the cDNA into small tubes and store at -20°C.

[0094] Fluorescence quantitative qPCR reaction: According to the instructions of VazymeChamQ SYBR qPCR Master Mix kit, 2 -△△ct Calculate relative gene expression.

[0095] (1) Fluorescence quantitative PCR primers were designed as shown in Table 3 and sent to Shanghai Sangon Biotechnology Co., Ltd. for synthesis.

[0096] Table 3 qPCR primer sequences

[0097]

[0098] (2) The reaction system is shown in Table 4:

[0099] Table 4 Reaction system

[0100]

[0101] (3) Reaction conditions are shown in Table 5:

[0102] Table 5 Reaction conditions

[0103]

[0104] Fluorescence quantitative PCR was used to examine the effects of GR24 and SAC treatments on genes involved in the Arabidopsis SL signaling pathway. The results, as shown in Table 6 below, show that both GR24 and SAC treatments significantly increased the expression of genes such as SMXL6, SMXL7, and SMXL8. After GR24 treatment, the expression levels of SMXL6, SMXL7, and SMXL8 were 3.86, 1.34, and 1.5 times higher than those in the control group, respectively. After SAC treatment, the expression levels of the three genes were 2.94, 2.09, and 7.68 times higher than those in the control group, respectively.

[0105] Table 6 Effects of different treatments on the expression of SL-related genes

[0106]

[0107] For the present invention, during the SL signal transduction process, SL is perceived by the receptor D14, inducing the formation of the SMXL6, 7, 8-D14-MAX2 complex, resulting in the degradation of SMXL6, 7, 8 through the ubiquitination-proteasome pathway, thereby relieving the inhibition of SMXL6, 7, 8 on downstream transcription factors and their own gene promoters. On the one hand, it activates the transcription of response genes such as BRC1, TCP1 and PAP1, and ultimately regulates biological processes such as plant branching and hypocotyl length; on the other hand, it relieves the inhibition of SMXL6, 7, 8 promoters and activates the expression of SMXL6, 7, 8 genes themselves, forming a negative feedback regulatory system to maintain the homeostasis of the SL pathway.

[0108] Example 5

[0109] This example tests the distribution of the fluorescent molecule SAC in Arabidopsis roots.

[0110] Arabidopsis thaliana Col-0 Seeds were surface-sterilized with 75% ethanol and rinsed 4-5 times with sterile water before being sown in MS medium and incubated at 4°C for 2 days to synchronize germination. The culture plates were incubated for 5 days under 16 h light / 8 h dark conditions at 22°C. Five-day-old seedlings were soaked in 1 / 2 MS liquid medium containing 1 μM, 2 μM, 5 μM, and 10 μM SAC for 30 minutes. The seedlings were then mounted on glass slides and imaged using confocal laser imaging in both brightfield and fluorescence fields, using a 20x objective lens and a 405 nm laser channel. Untreated seedlings were imaged using the same confocal imaging parameters.

[0111] The results are shown in Table 7 and Figure 3 As shown in Figure 3, compared with the blank control group (i.e., MOCK group), 5-d-old seedlings immersed in 5 μM SAC accumulated SAC in the cortex, endodermis, and stele cells, while very little SAC accumulated in the root epidermal cells and root tips.

[0112] Table 7 Effects of different SAC concentrations on fluorescence signals (fluorescence intensity unit: RFU)

[0113]

[0114] The above content describes the embodiments of the present invention in detail. However, the present invention is not limited to the above embodiments. Various modifications can be made within the scope of knowledge possessed by a person skilled in the art without departing from the spirit of the present invention. In addition, the embodiments of the present invention and the features thereof can be combined with each other unless there is a conflict.

Claims

1. An application of a fluorescent molecule in the preparation of a strigolactone inhibitor, characterized in that: The fluorescent molecule has a structural formula as shown in Formula I: Formula I.

2. Application of a fluorescent molecule in regulating plant growth, characterized in that: The fluorescent molecule has a structural formula as shown in Formula I: Formula I; The regulating plant growth is to promote the elongation of the hypocotyl of the plant seedling and / or promote the branch development of the plant.

3. The use according to claim 2, characterized in that The fluorescent molecule regulates plant growth by upregulating the gene expression levels of SMXL6, SMXL7 and SMXL8.

4. The use according to any one of claims 1 to 3, characterized in that The preparation method of the fluorescent molecule comprises the following steps: 5-Hydroxy-3-methylfuran-2(5H)-one and 7-isocyanato-4-methyl-2H-benzopyran-2-one are reacted in the presence of a base to obtain a compound represented by formula I.

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