Fluorescent molecule for inhibiting strigolactone signal as well as synthesis and application of fluorescent molecule

Abstract

The invention relates to the technical field of chemistry and agriculture, in particular to a fluorescent molecule for inhibiting strigolactone signals and synthesis and application of the fluorescent molecule. The fluorescent molecule for inhibiting the strigolactone signal has a structural formula as shown in a formula I which is described in the specification. The fluorescent molecule for inhibiting the strigolactones signal is simple in structure, easy to synthesize and high in biological activity, can inhibit the strigolactones signal, can be used as a novel plant growth regulating substance, can also be used as a fluorescent molecule in botany basic research, and is applied to indicating transportation, distribution and accumulation of strigolactones; and the formula I of the # imgabs0 # is shown in the specification.

Description

Technical Field

[0001] The present invention relates to the technical fields of chemistry and agriculture, and in particular to a fluorescent molecule that inhibits strigolactone signaling, as well as its synthesis and application. Background Art

[0002] Strigolactone (SL) is an important class of plant hormones, which plays a crucial role in plant branching / tillering regulation, parasitic seed germination, and plant-microbe interactions. At the same time, SL is widely involved in plant growth and development and environmental responses through interactions with other plant hormones. Therefore, the research on the mechanism of action of SL and the development of SL-based plant growth regulator (PGR) technical drugs are of great significance, and the relevant achievements have shown great application potential in crop genetic improvement, crop plant type regulation, and parasitic weed control. Unfortunately, the known SLs and their analogs (including agonists and inhibitors) are difficult to synthesize, have high production costs, and there are too few highly active species, making it difficult to apply them in agricultural production.

[0003] SL fluorescent molecules refer to compounds obtained by modifying or transforming the structure of SLs and their analogs, which have fluorescent signals and SL characteristics (including agonists and inhibitors), and can be used to visualize the accumulation and distribution of SLs in plants. They are important tools in the research on the synthesis, transport, and action mechanism of SLs. Currently, the number of fluorescent molecules that can be used as ideal SLs is very small because it is difficult to maintain high biological activity while obtaining good fluorescent properties. Generally, introducing a fluorescent skeleton into strigolactone is mainly achieved by changing the A ring and B ring, and previous attempts mainly focused on synthesizing aromatic heterocyclic compounds. A variety of SL fluorescent molecules, namely EGO and ST series probes, were synthesized by using nitrogen derivatives in the A ring in a highly conjugated binding manner. Among them, some probes have biological activity in promoting the germination of Orobanche seeds and the branching of fungal hyphae, but they still cannot meet the requirements of in vivo real-time imaging. Some research teams have also successively reported fluorescent molecules that inhibit SLs signaling, including a phthalocyanobenzoic acid derivative, or substituting the ether oxygen or phenolic ether oxygen in the D ring with a methylene group to synthesize new SLs antagonists, etc. Such antagonists have played some functions in inhibiting rice tillering or inhibiting parasitic seed germination, but there are few reports of highly active inhibitors or fluorescent molecules. Therefore, there is an urgent need to develop a new fluorescent molecule that affects strigolactone signaling.

[0004] The related prior art discloses a strigolactone promoter as a fluorescent probe. The promoter is mainly used to promote the germination of root parasitic seeds, inhibit the elongation of plant hypocotyls, inhibit plant branching / tillering, etc. While SL inhibitors (inhibiting SL signaling) mainly promote the elongation of plant hypocotyls, promote plant branching, and have an obvious yield-increasing effect on crops. SUMMARY OF THE INVENTION

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides a fluorescent molecule for inhibiting strigolactone signaling.

[0006] The present invention also provides a preparation method of the above-mentioned fluorescent molecule for inhibiting strigolactone signaling.

[0007] The present invention also provides an application of the above-mentioned fluorescent molecule for inhibiting strigolactone signaling.

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

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

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

[0011] According to one aspect of the present invention, there is provided a fluorescent molecule for inhibiting strigolactone signaling, and the fluorescent molecule for inhibiting strigolactone signaling has a structural formula shown in Formula I:

[0012] Formula I.

[0013] According to another aspect of the present invention, there is provided a preparation method of the above-mentioned fluorescent molecule for inhibiting strigolactone signaling, including the following steps: React 5-hydroxy-3-methylfuran-2(5H)-one with 7-isocyanato-4-methyl-2H-chromen-2-one in the presence of a base to obtain the compound shown in Formula I.

[0014] In some embodiments of the present invention, the solvent used in the reaction includes dichloromethane.

[0015] In some embodiments of the present invention, the mass ratio of 5-hydroxy-3-methylfuran-2(5H)-one, the base and 7-isocyanato-4-methyl-2H-chromen-2-one is 1:(0.5-1.5):(1-3).

[0016] In some embodiments of the present invention, the temperature of the reaction is 10-30°C.

[0017] In some embodiments of the present invention, the reaction time is 6-18 h.

[0018] In some embodiments of the present invention, the base includes an organic base and / or an inorganic base.

[0019] In some embodiments of the present invention, the base includes at least one of triethylamine, potassium carbonate, sodium carbonate, and cesium carbonate.

[0020] In some embodiments of the present invention, it further includes the step of purifying the compound shown in Formula I, and the purification is carried out by filtration and recrystallization for separation and purification. Among them, the solvent used for recrystallization can be dichloromethane:acetonitrile (v / v) = 2-4:1.

[0021] In some embodiments of the present invention, the preparation method further includes reacting triphosgene and 7-amino-4-methylcoumarin in the presence of a base to obtain 7-isocyanato-4-methyl-2H-chromen-2-one.

[0022] In some preferred embodiments of the present invention, the solvent used for the reaction includes dichloromethane.

[0023] 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).

[0024] In some embodiments of the present invention, the temperature of the reaction is 10-30 °C.

[0025] In some embodiments of the present invention, the reaction time is 6-18 h.

[0026] In some embodiments of the present invention, the base includes an organic base and / or an inorganic base.

[0027] In some embodiments of the present invention, the base includes at least one of triethylamine, potassium carbonate, sodium carbonate, cesium carbonate.

[0028] In some embodiments of the present invention, it further includes the step of purifying 7-isocyanato-4-methyl-2H-chromen-2-one, which includes adding an organic solvent to the obtained 7-isocyanato-4-methyl-2H-chromen-2-one, filtering, taking the filtrate, pickling, taking the organic phase, rotary evaporation, and recrystallization to obtain the product.

[0029] Preferably, the organic solvent can be n-hexane:dichloromethane (v / v) = 1:1-4.

[0030] Preferably, the pickling is carried out using at least one selected from hydrochloric acid, nitric acid, and sulfuric acid.

[0031] Preferably, the recrystallization includes first performing the first recrystallization with n-hexane:dichloromethane (v / v) = 1:1-3 and then performing the second recrystallization with dichloromethane:n-hexane (v / v) = 1:1-3.

[0032] According to another aspect of the present invention, there is provided the use of the above-mentioned fluorescent molecule that inhibits strigolactone signaling in any one of the following (1)-(4): (1) As a strigolactone inhibitor; (2) Regulate plant growth; (3) Prepare a fluorescent probe; (4) Detect strigolactone.

[0033] In some embodiments of the present invention, the concentration of the fluorescent molecule that inhibits strigolactone signaling as a strigolactone inhibitor is > 1 μM, for example, ≥ 2 μM, 2 - 200 μM, 2 - 100 μM, 2 - 80 μM, 2 - 60 μM, 2 - 40 μM, 2 - 20 μM, 2 - 10 μM, 2 - 5 μM.

[0034] In some embodiments of the present invention, the regulation of plant growth includes promoting the elongation of the hypocotyl of plant seedlings and / or promoting the branching development of plants. Further, the concentration of the fluorescent molecule that inhibits strigolactone signaling for promoting the elongation of the hypocotyl of plant seedlings and / or promoting the branching development of plants is > 1 μM, for example, ≥ 2 μM, 2 - 200 μM, 2 - 100 μM, 2 - 80 μM, 2 - 60 μM, 2 - 40 μM, 2 - 20 μM, 2 - 10 μM, 2 - 5 μM, ≥ 10 μM, 10 - 800 μM, 10 - 200 μM, 10 - 100 μM, 10 - 80 μM, 10 - 60 μM, 10 - 40 μM, 10 - 20 μM. Even further, the concentration of the fluorescent molecule that inhibits strigolactone signaling for promoting the elongation of the hypocotyl of plant seedlings is ≥ 2 μM, for example, 2 - 100 μM, 2 - 40 μM, 2 - 20 μM, 2 - 10 μM, 2 - 5 μM; the concentration of the fluorescent molecule that inhibits strigolactone signaling for promoting the branching development of the hypocotyl of plant seedlings is ≥ 10 μM, for example, 10 - 800 μM, 10 - 200 μM, 10 - 100 μM, 10 - 80 μM, 10 - 60 μM, 10 - 40 μM, 10 - 20 μM.

[0035] In some embodiments of the present invention, the fluorescent molecule that inhibits strigolactone signaling regulates plant growth by upregulating the gene expression levels of SMXL6, SMXL7, and SMXL8.

[0036] In some embodiments of the present invention, the plant includes Arabidopsis thaliana.

[0037] According to another aspect of the present invention, there is provided a plant growth regulator, and the plant growth regulator includes the above-mentioned fluorescent molecule that inhibits strigolactone signaling.

[0038] In some embodiments of the present invention, the plant growth regulator promotes the elongation of the hypocotyl of plant seedlings and / or promotes the branching development of plants. Further, in the plant growth regulator, the concentration of the fluorescent molecule that inhibits strigolactone signaling is > 1 μM, for example, ≥ 2 μM, 2 - 200 μM, 2 - 100 μM, 2 - 80 μM, 2 - 60 μM, 2 - 40 μM, 2 - 20 μM, 2 - 10 μM, 2 - 5 μM, ≥ 10 μM, 10 - 800 μM, 10 - 200 μM, 10 - 100 μM, 10 - 80 μM, 10 - 60 μM, 10 - 40 μM, 10 - 20 μM.

[0039] 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.

[0040] In some embodiments of the present invention, the plant includes Arabidopsis thaliana.

[0041] According to another aspect of the present invention, a method for regulating plant growth is provided, including treating a plant with the above-mentioned fluorescent molecule that inhibits strigolactone signaling at a concentration > 1 μM.

[0042] In some embodiments of the present invention, the regulation of plant growth includes promoting the elongation of the hypocotyl of plant seedlings and / or promoting the branching development of plants. The concentration of the fluorescent molecule that inhibits strigolactone signaling is ≥ 2 μM, for example, 2 - 200 μM, 2 - 100 μM, 2 - 80 μM, 2 - 60 μM, 2 - 40 μM, 2 - 20 μM, 2 - 10 μM, 2 - 5 μM, ≥ 10 μM, 10 - 800 μM, 10 - 200 μM, 10 - 100 μM, 10 - 80 μM, 10 - 60 μM, 10 - 40 μM, 10 - 20 μM. Further, the concentration of the fluorescent molecule that inhibits strigolactone signaling for promoting the elongation of the hypocotyl of plant seedlings is ≥ 2 μM, for example, 2 - 100 μM, 2 - 40 μM, 2 - 20 μM, 2 - 10 μM, 2 - 5 μM; the concentration of the fluorescent molecule that inhibits strigolactone signaling for promoting the branching development of plant seedlings is ≥ 10 μM, for example, 10 - 800 μM, 10 - 200 μM, 10 - 100 μM, 10 - 80 μM, 10 - 60 μM, 10 - 40 μM, 10 - 20 μM.

[0043] In some embodiments of the present invention, the fluorescent molecule that inhibits strigolactone signaling regulates plant growth by upregulating the gene expression levels of SMXL6, SMXL7, and SMXL8.

[0044] In some embodiments of the present invention, the plant includes Arabidopsis thaliana.

[0045] According to another aspect of the present invention, there is provided a fluorescent probe for detecting strigolactones in plants, comprising the above-mentioned fluorescent molecule that inhibits strigolactone signals.

[0046] In some embodiments of the present invention, the detection of strigolactones in plants comprises the following steps: introducing the above-mentioned fluorescent molecule that inhibits strigolactone signals into the plant body.

[0047] In some embodiments of the present invention, the plant includes Arabidopsis thaliana.

[0048] According to some embodiments of the present invention, there are at least the following beneficial effects: 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.

[0049] Other features and advantages of the present invention will be described in the following description, and in part, will be obvious from the description, or will be understood by implementing the present invention. Brief Description of the Drawings

[0050] The following further describes the present invention in conjunction with the drawings and examples, where: Figure 1 is the 1H NMR spectrum of compound SAC in Example 1 of the present invention; Figure 2 is the LC-MS test result diagram of compound SAC in Example 1 of the present invention; Figure 3 is the fluorescence confocal result diagram of the main root of Arabidopsis thaliana seedlings treated with 5 μM SAC in Example 5 of the present invention. Detailed Embodiments

[0051] The following will clearly and completely describe the concept and technical effects generated by the present invention in conjunction with the examples to fully understand the purpose, features, and effects of the present invention. Obviously, the described examples are only part of the examples of the present invention, not all examples. Other examples obtained by those skilled in the art based on the examples of the present invention without creative efforts belong to the scope of protection of the present invention.

[0052] When a numerical range is disclosed herein, the above range is considered continuous and includes the minimum and maximum values of the range, as well as each value therebetween. Further, when the range refers to integers, each integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0053] The terms "preferably", "more preferably", etc. in the present invention refer to embodiments of the present invention that can provide certain beneficial effects in certain cases. However, in the same or other cases, other embodiments may also be preferred. In addition, the recitation of one or more preferred embodiments does not imply that other embodiments are not available, nor is it intended to exclude other embodiments from the scope of the present invention.

[0054] Unless otherwise specified, "and / or" in the present invention is used to indicate that either or both of the stated situations may occur. For example, A and / or B includes (A and B) and (A or B).

[0055] Unless otherwise specified, "about" in the present invention means allowing an error within ±20%, further within ±10%, and still further within ±5%.

[0056] Unless otherwise specified, "room temperature" in the present invention means (25 ± 5)°C.

[0057] For those not specified with specific conditions in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not specified with the manufacturer, they are all conventional products that can be obtained by commercial purchase.

[0058] Example 1 This example provides a fluorescent molecule SAC for suppressing strigolactone signaling and its preparation method. Specifically, the preparation route is as follows:

[0059] Triphosgene (0.59 g, 2 mmol) was dissolved in 30 mL of dry DCM. Under stirring in an ice-water bath, 7-amino-4-methylcoumarin (0.97 g, 5.5 mmol) and triethylamine (1.5 mL) were added. The reaction was carried out overnight at room temperature, and the reaction of the starting material coumarin was monitored by TLC until it was complete. Then, 30 mL of n-hexane and 60 mL of DCM were added to obtain a suspension, which was filtered. The resulting 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 obtained solid was dispersed in 15 mL of n-hexane. 20 mL of DCM was added for pulping, and the filtered solid was dissolved in 30 mL of DCM and then dropped into 50 mL of n-hexane for precipitation. The obtained solid was filtered, and the white solid was the intermediate coumarin isocyanate, about 0.8 g.

[0060] 0.1 g of the above-obtained intermediate was dissolved in 15 mL of DCM, 0.07 g of 5-hydroxy-3-methyl-2(5H)-furanone and 0.05 mL of triethylamine were added, and the reaction was carried out overnight at room temperature. After the reaction of the intermediate was detected to be complete by TLC, the obtained suspension was filtered, and the obtained solid was pulped three times (20 mL×3) with dichloromethane:acetonitrile = 3:1 (v / v). The obtained solid was the final product SAC, about 62 mg.

[0061] The target product SAC synthesized in Example 1 was identified by 1H NMR and LC-MS techniques. The detection results are as Figure 1-2 shown. The mass spectrometry detection results showed that it was in the positive ion mode, with a molecular weight of 316.1, corresponding to M+H, and the results were consistent with the structure of SAC.

[0062] Furthermore, the present invention investigated the application of SAC as an SL inhibitor. SL inhibitors mainly showed promoting hypocotyl elongation of plants, promoting plant branching, etc.

[0063] Example 2 This example tested the effect of SAC on the hypocotyl growth of Arabidopsis thaliana.

[0064] 5 mM GR24 (CAS No.: 76974-79-3) and SAC stock solutions were prepared: Appropriate amounts of GR24 and SAC were weighed respectively with an electronic balance accurate to 0.0001 g, and GR24 and SAC were dissolved and fixed to 5 mM stock solutions with 1‰ DMSO (diluted with ultrapure water).

[0065] The culture medium for cultivating Arabidopsis thaliana is MS medium, which contains 4.4% MS powder, 3% sucrose, 0.7% agar, with the pH adjusted to 5.8. After autoclaving, before pouring the plates, filter-sterilized GR24, SAC, and a blank control (1‰ DMSO, i.e., the MOCK group) were added to the MS medium respectively. After addition, the final concentration of the compound GR24 in the medium was 5 μM, and the concentrations of SAC were 1 μM, 2 μM, 5 μM, and 10 μM respectively. Finally, sowing was completed. The Arabidopsis thaliana was cultured under weak light (16 h light, 8 h dark at 22 °C) for 6 d, and then the hypocotyl length of Arabidopsis thaliana was measured and statistically analyzed using the Digimizer measurement software. The measurement results were averaged.

[0066] The results are shown in Table 1 below. Compared with the hypocotyl length of the blank control group, the average hypocotyl length decreased after treatment with GR24. On the contrary, the use of SAC could significantly increase the hypocotyl length.

[0067] Table 1 Hypocotyl lengths (cm) after treatment with SAC and the control group

[0068] Example 3 This example tests the effect of SAC on the branching of Arabidopsis thaliana.

[0069] The Arabidopsis thaliana used was the wild-type Col-0. The seeds were disinfected with 75% ethanol for 15 min, washed 4 - 5 times with sterile water, and then vernalized in a 4 °C refrigerator for 3 d. They were sown into the MS complete medium and cultured for about 2 weeks. Then, seedlings with consistent growth were selected and transferred to nutrient soil for continued cultivation. They were cultured under strong sunlight lamps with a light cycle of 16 h light / 8 h dark and a temperature of about 22 °C. Before bolting, 10 μM, 20 μM, 40 μM, 80 μM, and 100 μM SAC and a 1‰ DMSO solution (i.e., the MOCK group) were dropped onto the axillary buds of Arabidopsis thaliana, about 2 mL per seedling, applied once every 4 d for a total of 4 times, with 30 plants in each group. The experiment took the average value. After bolting, photos were taken, and the number of branches in the rosette axils was counted. The results are shown in Table 2 below.

[0070] Table 2 Number of branches after treatment with SAC and the control group

[0071] Example 4 This example tests the effect of SAC on the expression of SL transcriptional repressor proteins.

[0072] In the presence of SL, D14 interacts with the corresponding F-box protein (such as MAX2 in Arabidopsis thaliana) through the SKP1-Cullin-F-box complex (SCF), and recruits SL transcriptional repressors (such as SMXL 6, 7, 8 in Arabidopsis thaliana), promoting the expression of SMXL 6, 7, 8 genes, thereby activating various SL physiological responses. Therefore, in this example, the response of SL to phenotypes such as plant branching and hypocotyl length and signal-related genes SMXL6, 7, 8, etc. is used to verify that SAC exerts a series of effects including regulating hypocotyl length through the SL signal transduction pathway. The specific verification steps are as follows: Sample treatment: Seeds of Arabidopsis thaliana wild-type Columbia ( col ) were disinfected, vernalized and then sown on MS medium, grown under 16 h light and 8 h dark (22 °C) for 8 d. After 8 d, the Arabidopsis thaliana seedlings were respectively placed in 1 / 2 MS liquid medium containing 10 μM GR24 and SAC and blank control for 4 h. After 4 h, the Arabidopsis thaliana seedlings were taken out, the excess reagents were washed off, dried on filter paper and then subjected to subsequent RT-PCR. The experiment was repeated 3 times.

[0073] Total RNA extraction: Using the Trizol method, prepare RNase-free pipette tips, EP tubes and PCR tubes. The mortar was soaked in 0.1% DEPC aqueous solution for 2 d, autoclaved at 121 °C for 20 min, and dried in a constant temperature drying oven.

[0074] Take about 100 mg of Arabidopsis thaliana seedlings (the Arabidopsis thaliana materials treated for 4 h above) and place them in a mortar containing liquid nitrogen, quickly grind them into a powder, transfer them to a 1.5 mL RNase-free EP tube, add 1 mL of Trizol extraction solution to each tube, blow and mix well with a pipette and vortex for 30 s, and place on ice for 10 min. Add 250 μL of chloroform and vortex to mix well, let stand on ice for 5 min, and centrifuge at 12000 rpm at 4 °C for 5 min. Transfer the supernatant to a new pre-cooled EP tube, add 0.6 times the volume of pre-cooled isopropanol, invert and mix well, and let stand on ice for 10 min. Centrifuge at 12000 rpm at 4 °C for 5 min and discard the supernatant. Add 75% ethanol to wash the precipitate 2 - 3 times (add 1 mL of 75% ethanol to resuspend and wash the precipitate, centrifuge at 12000 rpm at 4 °C for 5 min), and discard the excess supernatant. Dry in a laminar flow hood for about 10 min, add 30 - 50 μL of RNase-free water to dissolve the RNA. Measure the RNA concentration on an enzyme-linked immunosorbent assay (ELISA) reader, and detect and evaluate the RNA quality by 1% agarose gel electrophoresis. Finally, aliquot the RNA into 1 - 2 μg per tube and store at -80 °C.

[0075] cDNA synthesis: It was carried out according to the instruction manual of the Vazyme HiScript II Strand cDNA Synthesis Kit. The following reaction system was prepared on ice: 1 μg of total RNA, 4 μL of 4×gDNA wiper mix, 1 μL of Oligo dT, 1 μL of RandomHexamers, and nuclease-free H2O was added to make up to 16 μL. React at 42 °C for 2 min. The following components were added to the reaction system: 2 μL of 10×RT Mix and 2 μL of HiScript II Enzyme Mix, and mixed well. The annealing temperature was 25 °C for 5 min, the extension temperature was 50 °C for 15 min, and inactivated at 85 °C for 2 min to synthesize cDNA. The cDNA was aliquoted into small tubes and stored at -20 °C.

[0076] Fluorescent quantitative qPCR reaction: It was carried out according to the instruction manual of the Vazyme ChamQ SYBR qPCR Master Mix kit, and 2 -△△ct was used to calculate the relative gene expression level.

[0077] (1) The fluorescent quantitative PCR primers were designed as shown in Table 3 below and sent to Shanghai Sangon Biotech Co., Ltd. for synthesis.

[0078] Table 3 qPCR primer sequences

[0079] (2) The reaction system was as shown in Table 4 below: Table 4 Reaction system

[0080] (3) The reaction conditions were as shown in Table 5 below: Table 5 Reaction conditions

[0081] The effects of treatments such as GR24 and SAC on the genes related to the SL signaling pathway in Arabidopsis thaliana were detected by fluorescent quantitative PCR. The results are shown in Table 6 below. The treatments of GR24 and SAC significantly increased the expression levels of genes such as SMXL6, SMXL7, and SMXL8. After the GR24 treatment, the expression levels of the SMXL6, SMXL7, and SMXL8 genes were 3.86, 1.34, and 1.5 times that of the control group, respectively. After the SAC treatment, the expression levels of the three genes were 2.94, 2.09, and 7.68 times that of the control group, respectively.

[0082] Table 6 Effects of different treatments on the expression levels of SL-related genes

[0083] 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 the promoters of their own genes. On the one hand, it activates the transcription of response genes such as BRC1, TCP1, and PAP1, ultimately regulating biological processes such as plant branching and hypocotyl length; on the other hand, it relieves the inhibition on the promoters of SMXL6, 7, 8, activates the expression of the SMXL6, 7, 8 genes themselves, and forms a negative feedback regulation system to maintain the homeostasis of the SL pathway.

[0084] Example 5 In this example, the distribution of the fluorescent molecule SAC in Arabidopsis roots was tested.

[0085] Arabidopsis Col-0 After surface sterilizing the seeds with 75% ethanol and washing them 4 - 5 times with sterile water, they were sown on MS medium and placed at 4°C for 2 days for synchronous germination. The culture dishes were placed under the conditions of 16 h light / 8 h dark (22°C) for 5 days. 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 min, and then the seedlings were placed on glass slides and imaged under bright field and fluorescence field by laser confocal microscopy, with an objective lens magnification of 20 times and a laser channel of 405 nm. The untreated seedlings were imaged with the same parameters set for confocal microscopy.

[0086] The results are as shown in Table 7 below and Figure 3 As shown, compared with the blank control group (i.e., the MOCK group), when 5-day-old seedlings were soaked with 5 μM SAC, it was found that SAC accumulated in the cortical, endodermal, and stele cells, and very little SAC accumulated in the root epidermal cells and root tips.

[0087] Table 7 Effects of different concentrations of SAC on fluorescence signals (fluorescence intensity unit: RFU)

[0088] The above content has elaborated in detail on the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the gist of the present invention. In addition, without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

Claims

1. A fluorescent molecule that inhibits strigolactone signaling, characterized in that, Having a structural formula shown in Formula I: Formula I.

2. The preparation method of the fluorescent molecule for inhibiting strigolactone signal according to claim 1, characterized in that, Comprising the following steps: Reacting 5-hydroxy-3-methylfuran-2(5H)-one and 7-isocyanato-4-methyl-2H-chromen-2-one in the presence of a base to obtain the compound shown in Formula I.

3. Use of the fluorescent molecule for inhibiting strigolactone signaling according to claim 1 in any one of the following (1) to (4): (1) As a strigolactone inhibitor; (2) Regulating plant growth; (3) Preparing a fluorescent probe; (4) Detecting strigolactone.

4. The application according to claim 3, wherein The regulating of plant growth includes promoting the elongation of the hypocotyl of plant seedlings and / or promoting the branching development of plants.

5. The application according to claim 3, characterized in that, The fluorescent molecule for inhibiting strigolactone signaling regulates plant growth by upregulating the gene expression levels of SMXL6, SMXL7, and SMXL8.

6. A plant growth regulator, characterized in that, Containing the fluorescent molecule for inhibiting strigolactone signaling according to claim 1.

7. The plant growth regulator according to claim 6, wherein The plant growth regulator promotes the elongation of the hypocotyl of plant seedlings and / or promotes the branching development of plants.

8. The plant growth regulator according to claim 6, characterized in that, The plant growth regulator regulates plant growth by upregulating the gene expression levels of SMXL6, SMXL7, and SMXL8.

9. A fluorescent probe for detecting strigolactones in plants, characterized in that, Including the fluorescent molecule for inhibiting strigolactone signaling according to claim 1.

10. The fluorescent probe according to claim 9, characterized in that, The detecting of strigolactone in plants includes the following steps: introducing the fluorescent molecule for inhibiting strigolactone signaling into the plant body.

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