Method for improving drought tolerance of tomatoes based on arbuscular mycorrhizal fungi

Abstract

The invention discloses a method for improving drought tolerance of tomatoes based on arbuscular mycorrhizal fungi, and belongs to the technical field of agricultural microorganisms. According to the method, the drought tolerance of the tomatoes is enhanced by applying the preparation containing the arbuscular mycorrhizal fungi, the arbuscular mycorrhizal fungi are heterosporidium, active ingredients in the preparation exist in the forms of spores, hyphae, infected root segments and culture media, every 40 g of the preparation contains at least 100 heterosporidium spores, and carrier auxiliary materials can be added to improve the stability. The preparation is specifically applied to root systems when tomatoes are transplanted, and 40 g of the preparation is applied to each plant. The symbiotic effect is used for remarkably improving the drought resistance of the tomatoes, and the method has the advantages of being easy and convenient to operate, environmentally friendly, low in cost and wide in applicability, can be popularized in field or facility cultivation and is of great significance in guaranteeing the yield and quality of the tomatoes.

Description

Technical Field

[0001] This invention relates to the field of agricultural microbiology, and in particular to a method for improving the drought resistance of tomatoes based on arbuscular mycorrhizal fungi. Background Technology

[0002] Drought stress is one of the major abiotic stresses affecting global agricultural production, severely limiting the growth, development, and yield of vegetable crops. Tomatoes (Solanum lycopersicum), a widely cultivated and high-value vegetable, are rich in vitamins and minerals and hold a prominent position in the agricultural economy. However, tomatoes have shallow root systems and high transpiration rates, making them extremely sensitive to drought. Under drought stress, their growth process is disrupted, resulting in stunted plants, wilted leaves, and a significant decrease in photosynthetic efficiency, ultimately leading to poor fruit development, a sharp reduction in yield, and lower quality, severely impacting production efficiency.

[0003] Arbuscular mycorrhizal fungi (AMF) are a class of beneficial microorganisms in soil that can infect plant roots and establish symbiotic relationships with over 80% of terrestrial plants. Studies have confirmed that after forming a symbiotic relationship with plant roots, the extra-root hyphae of AM fungi can help the plant roots absorb water and nutrients from areas outside the root system, improving the plant's absorption of water and nutrients and enhancing its stress resistance. Plants in symbiosis with AM fungi can effectively enhance their tolerance to drought stress through two pathways. One is a direct effect: AM fungi directly absorb water through their extra-root hyphae, improving the plant's water status and increasing its drought resistance. The other is an indirect effect: AM fungi promote the formation of soil aggregates, improving root architecture, enhancing the absorption of mineral elements, increasing photosynthesis, and reducing oxidative damage. Furthermore, AM fungi can enhance the plant's osmotic regulation capacity, prompting the plant to synthesize and accumulate more osmotic substances such as proline, soluble sugars, and betaine, lowering the osmotic potential of cells, and enhancing their water-holding capacity. AM fungi can also induce the expression of a series of drought-related genes in plants through signal transduction pathways, regulate the physiological and biochemical processes of plants, and enhance their adaptability to drought stress. Previous studies have shown that under drought stress, inoculation with AM fungi significantly improved the water use efficiency of alfalfa, elm seedlings, oat seedlings, and sheepgrass seedlings compared to uninoculated seedlings. Studies have also investigated the mitigating effects of AM fungi on vegetable crops: for example, inoculation with AM fungi significantly increased the aboveground dry weight of onions under drought stress and promoted the growth of solanaceous vegetables.

[0004] Northwest my country is an arid and semi-arid region with low annual rainfall and scarce surface water resources. Drought is a significant factor affecting the development of the tomato industry in this region. Therefore, exploring the impact of mycorrhizal symbiosis on tomato growth under drought stress is of great significance in providing a theoretical basis for improving the drought resistance of tomatoes in arid environments. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings and deficiencies of the prior art and provide a method for improving the drought resistance of tomatoes based on arbuscular mycorrhizal fungi. It aims to break through the limitations of chemical regulation in traditional tomato drought resistance technology, which is prone to leaving residues, and achieve a green and efficient improvement in the drought resistance of tomatoes under drought stress.

[0006] This invention provides an application of arbuscular mycorrhizal fungi in improving the drought resistance of tomatoes.

[0007] This invention also provides the application of arbuscular mycorrhizal fungi in the preparation of formulations that improve the drought resistance of tomatoes.

[0008] Furthermore, the arbuscular mycorrhizal fungus is *Heteromorpha rhizocarpium*.

[0009] The present invention also provides a formulation for improving the drought resistance of tomatoes, characterized in that the active ingredient is arbuscular mycorrhizal fungi, and the active ingredient exists in the form of spores, root segments infected by mycelium, and culture medium.

[0010] Furthermore, the formulation also includes excipients.

[0011] Furthermore, each 40g of the preparation contains at least 100 Rhizocystis spores.

[0012] The present invention also provides a method for improving the drought resistance of tomatoes, characterized by including the step of applying the above-mentioned preparation to tomatoes.

[0013] Furthermore, the preparation is applied at the time of tomato transplanting and at the root system of the tomato plant.

[0014] Furthermore, the dosage of the preparation is 40g of the preparation per tomato plant.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] Rhizophagus irregularis, the core functional strain of this invention, exists in a complex form of spores, mycelia infecting root segments, and culture medium. Combined with suitable propagation adjuvants, the content of active spores is clearly quantified, providing a stable growth carrier for fungi and solving the pain points of ambiguous activity and fluctuating effects of traditional AM fungal preparations. The accompanying application method synchronizes the preparation with the tomato transplanting process, applying it directly to the root system without the need for complex equipment, which can significantly shorten the fungal infection distance, improve infection efficiency, and meet the needs of large-scale agricultural production.

[0017] The mycorrhizal symbiotic system constructed in this invention exhibits excellent environmental adaptability. Through multiple pathways, including regulating the expression of drought-resistant genes in tomatoes, optimizing photosynthetic system function, and enhancing antioxidant defense mechanisms, it stabilizes plant physiological metabolic activities, mitigates the inhibitory effect of drought stress on growth and development, and significantly improves the drought resistance of tomatoes. As a green technology based on the natural symbiotic mechanism of microorganisms, it involves no chemical intervention throughout the entire process, fully aligning with the modern agricultural green development concept. Long-term application can also improve soil microecological structure and enhance soil water and fertilizer retention capacity, providing an innovative solution with both technical feasibility and ecological value for the tomato industry in arid and semi-arid regions to overcome environmental limitations and achieve water-saving, efficient, and sustainable development. Attached Figure Description

[0018] Figure 1 The effect of AMF on mycorrhizal infection rate in tomatoes under drought stress; Figure 1 In the middle, A represents the mycorrhizal infection structure of tomato. Figure 1 In the middle, B represents the infection rate of AMF; Figure 1 In the figure, C represents the growth status of tomatoes; CK represents normal water; LD represents moderate drought stress; HD represents severe drought stress; AM represents inoculation with AMF; NM represents no inoculation with AMF; different letters represent significant differences between different treatments at the P < 0.05 level.

[0019] Figure 2 The effect of AMF inoculation on tomato biomass under different treatments was investigated; where CK represents normal water conditions; LD represents moderate drought stress; HD represents severe drought stress; AM represents AMF inoculation; and NM represents no AMF inoculation. Figure 2 Fresh weight of the aboveground parts of plant A; Figure 2 Dry weight of the aboveground part of the middle B section; Figure 1 Fresh weight of the underground part of C; Figure 1 Root-to-crown ratio in the middle D region;

[0020] Figure 3 The effect of AMF inoculation on chlorophyll content in tomato leaves under different treatments;

[0021] Figure 4The effects of AMF inoculation on tomato photosynthesis under different treatments; Figure 4 In the middle, A represents porosity; Figure 4 In this context, B represents the net photosynthetic rate. Figure 4 In this context, C represents the transpiration rate. Figure 4 D represents the intercellular CO2 concentration;

[0022] Figure 5 The effects of AMF inoculation on tomato root structure under different treatments; Figure 5 In the middle, A represents the root length (cm). Figure 5 In this context, B represents the root surface area (cm²). Figure 5 In this context, C represents the root volume (cm³). Figure 5 D represents the root tip density (number of roots / cm³).

[0023] Figure 6 The effects of AMF inoculation under different treatments on the nutrient content of tomatoes; Figure 6 In the middle, A represents the phosphorus content; Figure 6 B represents the potassium content; Figure 6 C represents calcium content; Figure 6 D represents the copper content; Figure 6 E represents the magnesium content; Figure 6 F represents the iron content; Figure 6 G represents the manganese content; Figure 6 H in the text represents the sodium content; Figure 6 In the middle, I represents the zinc content;

[0024] Figure 7 The effect of AMF inoculation on tomato enzyme activity under different treatments; Figure 7 A represents superoxide dismutase activity; Figure 7 B represents peroxidase activity; Figure 7 C represents catalase activity;

[0025] Figure 8 Two-dimensional scatter plots of orthogonal-partial least squares discriminant analysis (OPLS-DA) of tomato indicators for different treatment groups;

[0026] Figure 9 Scatter plot of permutation test for orthogonal-partial least squares discriminant analysis (OPLS-DA) of tomato indicators for different treatment groups;

[0027] Figure 10 Effects of AMF inoculation on gene expression in SlNIPs under different treatments; Figure 10 In the figure, A represents the expression level of SlNIP1.1; Figure 10 In the figure, B represents the expression level of SlNIP2.1; Figure 10 C represents the expression level of SlNIP3.2. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Example 1

[0030] 1. Materials and Methods

[0031] 1.1 Test Materials

[0032] The arbuscular mycorrhizal fungus Rhizophagus irregularis Ri was provided by the Beijing Academy of Agricultural and Forestry Sciences. White clover was used as the host for the propagation of the fungal agent. The substrate was sterilized river sand. The inoculum after propagation included spores, mycelia, fully infected root segments, and culture medium as the fungal agent.

[0033] Micro-Tomato, a type variety with small plant size and short growth period, was sterilized by soaking in a 10% NaClO solution for 10 minutes, rinsing with distilled water, and then placed on sterilized filter paper. It was then cultured in a dark incubator at 28℃ for 48 hours. After germination, seeds with uniform germination were sown in 50-cell trays containing sterilized vermiculite and sand (volume ratio 1:1). Two weeks after germination, seedlings with uniform growth were transplanted into 1L plastic pots (the pots were sterilized with NaClO before transplanting). The substrate for the potted experiment was river sand. The river sand was sieved (2mm) and repeatedly rinsed with tap water until the supernatant was clear. After drying, it was sterilized in a high-pressure steam sterilizer at 121℃ for 1 hour.

[0034] 1.2 Experimental Design

[0035] A two-factor completely randomized design was adopted, with three water treatments: normal water supply (CK): the substrate moisture content was maintained at 90% of field capacity; moderate drought (LD): the substrate moisture content was 65% of field capacity; and severe drought (HD): the substrate moisture content was controlled at 45% of field capacity. An inoculation treatment was also set up (AM: inoculation Ri; NM: inactivated fungicide of inoculation Ri), for a total of 6 treatments, with 6 replicates for each treatment, for a total of 36 pots.

[0036] At transplanting, tomatoes were inoculated with 40g of inoculum (containing approximately 100 spores, infected root segments, mycelium, propagation sand, and culture medium) at the root system. The control group was inoculated with an equal mass of sterilized AMF inoculum. To provide a similar microbial community without AMF, 10mL of inoculum solution was added to the control group. The inoculum solution was prepared by dissolving an appropriate amount of inoculum in sterile deionized water, stirring, and then filtering through a <20µm filter membrane. The plants were irrigated weekly with 400mL of low-phosphorus nutrient solution. Three weeks after AMF inoculation, drought stress was applied, and the moisture content of each treatment was controlled by weighing. Tomato seedlings were harvested three weeks after drought stress treatment.

[0037] The experiment was conducted in the greenhouse of Gansu Agricultural University (average daytime temperature 27.5℃, average nighttime temperature 17.4℃, humidity maintained between 75% and 86%). The pots were randomly changed twice a day during the cultivation period for all experiments.

[0038] 1.3 Measurement Indicators

[0039] 1.3.1 Mycorrhizal infection rate

[0040] Tomato plants were removed from the substrate, and the roots were rinsed with clean water to remove surface impurities. The root samples were stained with trypan blue. The stained root samples were observed using an optical microscope, and the root segments infected with AMF were recorded using a grid cross-section method. The mycorrhizal infection rate was calculated using the formula: "Infection rate (%) = (Number of infected cross-sections / Total number of observed cross-sections) × 100".

[0041] 1.3.2 Plant growth indicators and physiological indicators

[0042] At harvest, measure the fresh and dry weight of the aboveground and underground parts of the plant. Root-to-shoot ratio = underground biomass / aboveground biomass.

[0043] Total root length, root surface area, root volume, and root tip density were measured using a scanner (EPSON V800, Japan) to acquire root images for each treatment, which were then analyzed using WinRhizo software (LC4800-Ⅱ LA2400; Sainte-Foy, Canada).

[0044] Superoxide dismutase (SOD) activity was determined in the leaves of harvested plants using the nitroblue tetrazolium (NBT) photochemical reduction method. Peroxidase (POD) activity was determined using the guaiacol colorimetric method, and catalase (CAT) activity was determined using the ultraviolet absorption method.

[0045] 1.3.3 SPAD value and photosynthetic parameters

[0046] Before harvest, on a sunny morning (8:00-11:00), the 2nd-3rd leaves from the upper middle section were selected for chlorophyll SPAD value and photosynthetic parameters. Chlorophyll SPAD value was measured using a handheld chlorophyll meter (SPAD-502Plus). Photosynthetic parameters were measured using a CIRAS-2 portable photosynthesis system (CIRAS-2, UK) with the following parameters: light intensity 1000 µmol / (m².s), leaf chamber CO2 concentration 400 µmol / mol, airflow rate 500 ml / min, leaf chamber temperature 25℃, and an open airflow path. Measurements were repeated three times for each leaf. Net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), and transpiration rate (Tr) were recorded.

[0047] 1.3.4 Determination of nutrient element content in aboveground parts

[0048] The determination of non-metallic element phosphorus (P) was performed using the molybdenum-antimony colorimetric method; the determination of metallic elements such as potassium (K), calcium (Ca), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) was performed using atomic absorption spectrometry.

[0049] 1.3.5 Quantitative Fluorescence Expression Analysis of Tomato SlNIP Gene Family Members in Response to AMF Co-occurrence

[0050] Specific primers for the SlNIP gene family were designed using the NCBI website, with products controlled at 80-150 bp. Tomato's UBIqutin and EF were selected as internal reference genes (Table 1). RNA was extracted from tomato roots using the Trizol method, and cDNA was reverse transcribed using the Adley TRUEscript RT kit (+Gdna Eraser). Fluorescent quantitative analysis of the NIP genes was performed using Novizan's TB Green® Premix Ex Taq™ II kit. The relative expression levels of candidate genes were calculated using the formula... Calculations were performed. All qRT-PCR reactions were repeated three times.

[0051] Table 1 Primer sequences for the tomato NIP gene

[0052]

[0053] 1.4 Data Processing

[0054] Data processing, correlation analysis, and tests for normality and homogeneity of variance were performed using SPSS 22 (SPSS Inc., Chicago, IL, United States). Two-way ANOVA was used to investigate the effects of AMF inoculation, drought stress, and their interaction on the indicators. One-way ANOVA was used to test differences between groups (P < 0.05 was considered significant). Bar charts were generated using Origin, and OPLS-DA analysis was performed online through the Bioincloud website (https: / / www.bioincloud.tech).

[0055] 2 Results and Analysis

[0056] 2.1 Effects of AMF on the growth of tomato seedlings under drought stress

[0057] As shown in Figure (1-A), AMF inoculation formed infection structures in the tomato roots, while no infection was observed in the uninoculated tomato roots. Under the CK, LD, and HD treatments, the mycorrhizal infection rates of tomatoes were 18%, 38%, and 11%, respectively. The mycorrhizal infection rates under the CK and HD conditions were significantly lower than those under the LD treatment. Figure 1 -B). As drought stress increases, tomato seedling leaves gradually curl. Under the same drought stress conditions, seedlings inoculated with AMF show reduced drought stress symptoms. Figure 1 -C).

[0058] Tomatoes are harvested after 6 weeks of growth. Figure 2 It was found that, under different water treatments, tomato seedlings inoculated with AMF showed a significant advantage in biomass. Under the LD treatment, the aboveground fresh weight of AMF-inoculated seedlings was significantly higher than that of the uninoculated treatment, increasing by 77.91%, and the aboveground dry weight increased by 44.94%; the root-to-shoot ratio was significantly reduced by 50%. Under the HD treatment, the AMF-inoculated treatment significantly increased the aboveground dry weight by 59.59%; the aboveground fresh weight increased by 47.32%, and the root-to-shoot ratio decreased by 19.05%. Under normal water treatment, there was no significant difference between the inoculated and uninoculated treatments.

[0059] 2.2 Effects of AMF on chlorophyll content and photosynthetic parameters in tomato under drought stress

[0060] Depend on Figure 3It was found that AMF inoculation significantly increased the chlorophyll content of tomato seedlings under both LD and HD treatments (average increases of 12.28% and 12.47%, respectively); under CK treatment, AMF inoculation had no significant effect on leaf chlorophyll content. Compared with uninoculated plants, AMF inoculation in CK treatment significantly increased Tr, Gs, and Ci in tomato leaves, by 41.69%, 43.16%, and 17.06%, respectively; under LD treatment, AMF inoculation significantly increased Gs, Pn, and Tr, by 52.08%, 41.15%, and 84.17%, respectively; under HD treatment, AMF inoculation significantly increased Ci in tomato leaves, but had no significant effect on other photosynthetic indicators (due to...). Figure 4 (As shown).

[0061] 2.3 Effects of AMF on Tomato Root Structure under Drought Stress

[0062] Compared with the uninoculated AMF treatment, the LD treatment significantly increased root tip density (by 62.49%), while the HD treatment significantly decreased root tip density by 54.99%, likely due to root growth restriction caused by extreme drought. Root length, root surface area, and root volume had no significant effect. Under the three water conditions, AMF inoculation resulted in varying degrees of reduction in root volume, decreasing by 24.99%, 7.04%, and 13.67%, respectively. Figure 5 (As shown).

[0063] 2.4 Effects of AMF on Nutrient Content in Tomatoes under Drought Stress

[0064] Depend on Figure 6 It can be seen that under LD treatment, inoculation with AMF significantly increased the phosphorus content of plants by 9.15%, while AMF had no significant effect on the phosphorus content of plants under both CK and LD water treatments. Figure 6 -A); Under LD and HD treatments, the potassium content of tomato plants inoculated with AMF was significantly increased, by 24.46% and 17.66% respectively compared with the control. Figure 6 -B). Compared with uninoculated AMF, the calcium content of inoculated AMF decreased under the three moisture treatments, by 3.24%, 18.92%, and 13.37%, respectively. Figure 6 Under CK and HD treatments, AMF inoculation had no significant effect on copper content in tomatoes compared to uninoculated tomatoes. However, under LD treatment, the copper content in the inoculated treatment was significantly lower than that in the uninoculated treatment, decreasing by 80.24%. Figure 6 -D). Under HD treatment, AMF inoculation significantly reduced magnesium content ( Figure 6Under CK and LD treatments, AMF inoculation significantly increased plant iron content, by 65.1% and 5.2%, respectively. However, under HD treatment, there was no significant difference between AMF inoculation and non-inoculation. Figure 6 -F). Under the three water treatments, AMF inoculation had no significant effect on the manganese, sodium, and zinc content in the aboveground parts of tomatoes compared to the uninoculated treatment. Figure 6 -G~I).

[0065] 2.5 Effects of AMF inoculation on enzyme activity in tomato leaves under drought stress

[0066] Depend on Figure 7 It can be seen that, under CK treatment, compared with uninoculated AMF, AMF inoculation significantly reduced POD activity in tomato leaves by 13.93%; under LD treatment, AMF inoculation significantly reduced POD activity in tomato leaves and significantly increased CAT activity in tomato leaves, but had no significant effect on SOD activity; under HD treatment, AMF inoculation significantly increased CAT activity in tomato leaves by 51.50%.

[0067] 2.6 Two-way ANOVA of AMF on physiological indicators of tomato plants under drought stress

[0068] As shown in Table 2, drought stress treatments significantly affected all parameters except for aboveground dry weight, root tip density, Pn, and magnesium content. AMF inoculation significantly affected aboveground fresh weight, aboveground dry weight, root-to-shoot ratio, SPAD, Pn, Tr, Gs, Ci, calcium, copper, iron, potassium, magnesium content, and POD activity. The interaction between AMF and SPAD significantly affected root-to-shoot ratio, root tip density, SPAD, Tr, Gs, potassium content, SOD activity, and POD activity.

[0069] Table 2. Two-way ANOVA analysis of AMF on physiological indicators of tomato plants under drought stress.

[0070]

[0071] 2.7 Orthogonal-Partial Least Squares Discriminant Analysis (OPLS-DA) of Tomato Indicators

[0072] Depend on Figure 8 It can be seen that the normal water treatment group and the drought stress treatment group were clearly distinguished, and the non-inoculation treatment and the inoculation treatment under drought stress ( Figure 8 The groups were also clearly separated. Infection rate, Fe, Ca, Cu, root-to-shoot ratio, SPAD, and CAT activity were the most significant influencing factors for differences between groups. Figure 9 Their high VIP values ​​and high significance indicate that they play a decisive role in grouping discrimination.

[0073] 2.8 Expression levels of NIP-related genes

[0074] Three NIP family genes were identified and analyzed using quantitative real-time PCR. AMF-inoculated and uninoculated tomato roots were analyzed using qRT-PCR. Figure 10 The results showed that, compared with the control, AMF inoculation significantly upregulated the expression of SlNIP1.1, SlNIP2.1 and SlNIP3.2 genes, especially SlNIP1.1, which was significantly highly expressed in the roots inoculated with AMF. We speculate that it may be a mycorrhizally induced gene.

[0075] 3. Conclusion

[0076] This study investigated the effects of AMF inoculation on infection rate, biomass, chlorophyll content, photosynthetic indicators, root morphology, mineral nutrients, stress-resistant enzyme activity, and SlNIPs gene expression under different water conditions. The results showed that water conditions significantly affected the symbiotic effect between AMF and tomato. Moderate drought significantly promoted AMF infection of tomato roots, and under moderate drought stress, AMF inoculation significantly increased the aboveground fresh weight of tomatoes. Under drought stress, AMF inoculation significantly affected tomato leaf chlorophyll content, photosynthetic indicators, and the activity of antioxidant enzymes. Under moderate drought stress, AMF inoculation significantly increased the content of nutrients (phosphorus, potassium, calcium, and iron), and the interaction between AMF and AMF significantly affected root tip density, SPAD, Tr, Gs, potassium content, SOD activity, and POD activity. OPLS-DA analysis showed that infection rate, Fe, Ca, Cu, SPAD, and CAT activities were the most significant influencing factors among groups, and under drought stress, AMF inoculation significantly upregulated the expression of the SlNIP1.1 gene. In conclusion, inoculation with AM fungi can effectively alleviate the growth stress caused by drought on tomatoes.

[0077] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. Application of arbuscular mycorrhizal fungi in improving drought resistance in tomatoes.

2. Application of arbuscular mycorrhizal fungi in the preparation of agents to improve the drought resistance of tomatoes.

3. The application according to claim 1 or 2, characterized in that, The arbuscular mycorrhizal fungus is *Heteromorpha rhizocarpium*.

4. A preparation for improving the drought resistance of tomatoes, characterized in that, The active ingredient is arbuscular mycorrhizal fungi, which exist in the form of spores, hyphae, infected root segments, and culture medium.

5. The formulation according to claim 4, characterized in that, The formulation also includes excipients, wherein the excipients are carrier excipients.

6. The formulation according to claim 4 or 5, characterized in that, Each 40g of the preparation contains at least 100 Heteromorphospora spores.

7. A method for improving the drought resistance of tomatoes, characterized in that, The step includes applying the preparation of any one of claims 4-6 to tomatoes.

8. The method according to claim 7, characterized in that, The preparation is applied when tomatoes are transplanted, and at the root system of the tomatoes.

9. The method according to claim 7 or 8, characterized in that, The dosage of the preparation is 40g per tomato plant.

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