Application of exogenous L-tryptophan in improving growth and insect resistance of lettuce
By applying L-tryptophan exogenously, the expression of lettuce defense genes is activated, which solves the problem of pest infestation during lettuce growth and achieves simultaneous improvement in lettuce growth and pest resistance. It has significant promoting effects and environmentally friendly characteristics.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-08
- Publication Date
- 2026-03-13
AI Technical Summary
In the current technology, lettuce is often attacked by pests such as beet armyworm during its growth, which leads to a decline in yield and quality. Furthermore, chemical pesticide control is prone to causing pesticide resistance and environmental pollution, and there is a lack of environmentally friendly pest management strategies.
Exogenous application of L-tryptophan, applied four times a week at a concentration of 2mM through root irrigation and foliar spraying, activates the expression of lettuce's defense genes LsPPO3 and LsPPO4, enhancing its insect resistance.
It significantly promotes lettuce growth, increases plant height and biomass, improves yield and quality, while enhancing resistance to beet armyworm, activating defense mechanisms, and is environmentally friendly and easy to operate.
Smart Images
Figure CN121647262A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the fields of agricultural biotechnology and plant protection, specifically relating to the effect of exogenous L-tryptophan on improving the performance of lettuce (…). Lactuca sativa Application of L. in the growth and insect resistance of lettuce. More specifically, this invention provides a method for simultaneously promoting lettuce growth and development and enhancing its resistance to the beet armyworm (L.) through exogenous application of L-tryptophan. Spodoptera litura The resistance method is characterized by its simplicity, environmental friendliness, and significant effects, and has important application value in modern green agricultural production. Background Technology
[0002] Lettuce is an important leafy vegetable, widely cultivated globally. However, it is frequently attacked by various pests during its growth, with the beet armyworm being one of the major pests, leading to decreased yield and quality. Currently, the control of the beet armyworm mainly relies on chemical pesticides, but long-term use can easily lead to pesticide resistance, environmental pollution, and food safety issues. Therefore, developing environmentally friendly and sustainable pest management strategies is crucial.
[0003] Plant defense mechanisms can be activated by exogenous signaling molecules. L-tryptophan is an essential amino acid that participates in various plant metabolic pathways, regulating the production of stress-resistant substances such as flavonoids and alkaloids. These metabolites play an important role in plant responses to adverse conditions. Lettuce is often affected by insect pests, impacting its quality and yield. Currently, research on how L-tryptophan regulates lettuce's insect resistance is still fragmented, and its role in lettuce's insect resistance has not been systematically studied. Summary of the Invention
[0004] The purpose of this invention is to provide an application of exogenous L-tryptophan in improving the growth and insect resistance of lettuce, so as to solve the problems of growth inhibition and complicated operation of insect-resistant treatment in the prior art.
[0005] The technical solution adopted in this invention is as follows: The first aspect is to provide an application of exogenous L-tryptophan in improving the growth and insect resistance of lettuce, by applying L-tryptophan exogenously to lettuce plants.
[0006] Furthermore, the application concentration of L-tryptophan is 2 mM.
[0007] Furthermore, the L-tryptophan is obtained through a combination of root irrigation and foliar spraying.
[0008] Furthermore, apply once a week for a total of four times.
[0009] Furthermore, the insect resistance is specific to lepidopteran pests.
[0010] Furthermore, the lepidopteran pest is the beet armyworm.
[0011] Furthermore, the growth promotion is manifested as a significant increase in plant height, aboveground fresh weight, and underground fresh weight.
[0012] Furthermore, the application can also upregulate lettuce defense-related genes. LsPPO3 and LsPPO4 The expression.
[0013] Secondly, a method for improving lettuce growth and insect resistance is provided, including the exogenous application of L-tryptophan to lettuce plants.
[0014] Thirdly, a lettuce cultivation composition is provided, comprising an effective amount of L-tryptophan as an active ingredient, for promoting lettuce growth and enhancing insect resistance.
[0015] The beneficial effects of this invention are as follows: This invention achieves simultaneous improvement in lettuce growth and insect resistance through exogenous application of L-tryptophan, which has outstanding advantages.
[0016] Significant growth-promoting effects: L-tryptophan treatment significantly increased lettuce plant height and biomass, improving yield and quality, with plant height increasing by 17.41%, above-ground fresh weight increasing by 95.64%, and underground fresh weight increasing by 78.52%.
[0017] Significantly enhanced insect resistance: The treated lettuce showed strong resistance to the beet armyworm, with larvae weight reduced by 38.97%, and also had a certain control effect on other pests.
[0018] Activating defense mechanisms: L-tryptophan can be specifically upregulated under pest stress. LsPPO3 and LsPPO4 The expression of defense genes activates the plant's active defense system.
[0019] Environmentally friendly and safe: L-tryptophan is a natural amino acid that is easily degraded and leaves no residue. It will not pollute the environment and is in line with the development direction of green agriculture.
[0020] Simple and convenient to operate: simply spray on leaves or irrigate the roots. No special equipment is required, making it easy for farmers to master and with low barriers to promotion.
[0021] Excellent cost-effectiveness: low input costs, significant increase in production, and substantial economic benefits.
[0022] Good compatibility: It can be used in conjunction with other cultivation measures and pest and disease control methods, and is easy to integrate into existing production systems.
[0023] This invention discovers that exogenous L-tryptophan can not only significantly promote lettuce growth, but also effectively enhance its resistance to beet armyworm, while upregulating the expression of defense genes, overcoming the growth inhibition defects of JA treatment, and has important application value.
[0024] This invention, through systematic experimental research, reveals the dual role of L-tryptophan in promoting lettuce growth and enhancing its insect resistance, and elucidates its mechanism of action, providing a new solution for pest control in lettuce cultivation. Attached Figure Description
[0025] Figure 1 The effect of exogenous application of L-tryptophan (L-Trp) on the overall growth and development of lettuce.
[0026] Figure 2 The effects of different treatments (CK, L-Trp) on lettuce plant height.
[0027] Figure 3 The effects of different treatments (CK, L-Trp) on the fresh weight of lettuce stems and roots.
[0028] Figure 4 The effects of different treatments (CK, L-Trp) on the bollworm resistance of lettuce.
[0029] Figure 5 It is exogenous L-tryptophan that protects lettuce against its defense genes. LsPPO3 The impact of expression.
[0030] Figure 6 It is exogenous L-tryptophan that protects lettuce against its defense genes. LsPPO4 The impact of expression. Detailed Implementation
[0031] The present invention will now be described in detail with reference to the embodiments and accompanying drawings.
[0032] Example 1: Effects of exogenous L-tryptophan on lettuce growth Materials and Methods: The lettuce variety tested was 'Roman' lettuce. Lactuca sativa The experiment was conducted in a plant factory, using nutrient soil and maintaining suitable light, temperature and humidity conditions.
[0033] The experiment consisted of two treatment groups: a control group (CK, distilled water treatment) and an L-tryptophan treatment group (L-Trp, 2 mM). Each treatment had 6 replicates, with 10 lettuce plants per replicate.
[0034] Preparation of tryptophan solution: Exogenous L-tryptophan (L-Trp; CAS No. 73-22-3) was purchased from Macklin Biochemical Co., Ltd. (catalog number T655568-100g, purity ≥99%). A stock solution of approximately 50 mM was prepared by dissolving 1.02 g of L-Trp in 100 mL of ultrapure water, followed by filtration through a 0.22 μm filter membrane. Before use, the solution was diluted 1:100 to obtain a 500 μM working solution.
[0035] The measured parameters include plant height, aboveground fresh weight, and underground fresh weight. Plant height was measured using a ruler from the substrate surface to the growing point; aboveground fresh weight was measured using an electronic balance; and underground fresh weight was measured by carefully removing the roots, washing and drying them.
[0036] result: Plant height measurements showed that the average plant height in the CK group ranged from 7.0456 to 9.0384 cm, while the average plant height in the L-Trp group ranged from 8.2594 to 10.5341 cm, representing an increase of 17.41% compared to the CK group. Statistical analysis indicated that the difference between the two groups was statistically significant. Figure 1 , Figure 2 ,in Figure 1 The two lettuce heads at the top and the two heads at the bottom are from the same plant, viewed from both above and below.
[0037] The aboveground fresh weight determination showed that the average aboveground fresh weight of the CK group was between 2.2784 and 3.4852 g, while that of the L-Trp group was between 5.4815 and 6.3276 g, representing an increase of 95.64% compared to the CK group. The difference was highly significant. Figure 3 ).
[0038] Fresh weight measurements of the underground parts showed that the average fresh weight of the underground parts in the CK group ranged from 2.4372 to 3.1285 g, while that in the L-Trp group ranged from 4.4396 to 5.2649 g, representing an increase of 78.52% compared to the CK group. The difference was highly significant. Figure 3 ).
[0039] Example 2: Effects of exogenous L-tryptophan on insect resistance in lettuce Materials and Methods: In the experiment, six fourth-instar larvae were placed on each plant, and six plants were set up in each group. Leaf samples were collected 5 days (5 d) and 8 days (8 d) after treatment, and the growth inhibition effect was evaluated by weighing the larvae.
[0040] The larvae used in the experiment were Spodoptera litura, one of the most important leaf-eating pests in lettuce cultivation. The larvae are voracious eaters, and once an outbreak occurs, they can devour an entire head of lettuce in a short time, leading to yield losses exceeding 30%, or even total crop failure. Spodoptera litura has a short lifespan, a stable source of insects, and is easy to replicate in experiments.
[0041] result: The results of larval weight measurements showed that the average weight of larvae in the CK group ranged from 174.6 to 281.4 mg, while the average weight of larvae in the L-Trp group ranged from 78.7 to 184.7 mg, a decrease of 38.97% compared to the CK group. Figure 4 Statistical analysis showed that the difference between the two groups was highly significant.
[0042] Further observation revealed that the L-Trp group larvae were not only lighter in weight but also less active and consumed significantly less food. This indicates that L-tryptophan treatment not only directly affects larval growth and development but may also influence larval feeding behavior by altering the physicochemical properties of lettuce.
[0043] Example 3: Effects of exogenous L-tryptophan on the expression of defense genes in lettuce Materials and Methods: Detecting genes LsPPO3 and LsPPO4 These two genes encode polyphenol oxidase, which is a key gene in plant defense responses.
[0044] The experimental treatments included a CK group and an L-Trp group. Each treatment had four biological replicates.
[0045] Sampling was conducted before inoculation, on day 5 post-inoculation, and on day 8 post-inoculation. Samples were taken at each time point, flash-frozen in liquid nitrogen, and stored at -80°C for later use.
[0046] The detection method used was qRT-PCR.
[0047] result: Pre-inoculation test results showed that the L-Trp group and the CK group were... LsPPO3 and LsPPO4 No significant difference was observed in gene expression, indicating that L-tryptophan treatment does not continuously activate defense gene expression in the absence of pest stress. Five days after inoculation, the L-Trp group... LsPPO3 The expression level was significantly higher in the control group than in the control group. Meanwhile, LsPPO4 The genes also showed a similar upregulation trend. Eight days after inoculation, the L-Trp group... LsPPO3 The expression level was still higher than that of the CK group, but the upregulation rate was lower than that on day 5. LsPPO4 Gene expression also exhibits a similar pattern of change. Figure 5 and Figure 6 ).
[0048] The results showed that exogenous jasmonic acid could maintain LsPPO3 and LsPPO4 High expression levels of these substances promote long-term activation of lettuce's defense mechanisms.
[0049] This invention systematically demonstrates the dual role of exogenous L-tryptophan in improving lettuce growth and insect resistance. Through multiple mechanisms, including promoting growth, enhancing insect resistance, and activating defense gene expression, it achieves a synergistic improvement in lettuce growth and defense. Furthermore, L-tryptophan treatment has significant advantages such as remarkable effectiveness, ease of operation, environmental friendliness, and low cost, making it suitable for widespread application in modern green agricultural production and providing reliable technical support for practical production.
[0050] Example 4: This embodiment also provides a lettuce cultivation composition containing an effective amount of L-tryptophan as an active ingredient for promoting lettuce growth and enhancing insect resistance. The composition and preparation method are as follows: 1.02 g of L-tryptophan is dissolved in 100 mL of ultrapure water, followed by filtration through a 0.22 μm membrane to prepare a stock solution of approximately 50 mM. Before use, it is diluted 1:100 to obtain a working solution (500 μM).
[0051] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only.
[0052] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.
Claims
1. The application of exogenous L-tryptophan in improving lettuce growth and insect resistance, characterized in that, Apply L-tryptophan exogenously to lettuce plants.
2. The application according to claim 1, characterized in that, The application concentration of L-tryptophan was 2 mM.
3. The application according to claim 1, characterized in that, The L-tryptophan is obtained through a combination of root irrigation and foliar spraying.
4. The application according to claim 3, characterized in that, Apply once a week for a total of four times.
5. The application according to claim 1, characterized in that, The insect resistance is specifically targeted at lepidopteran pests.
6. The application according to claim 5, characterized in that, The lepidopteran pest in question is the beet armyworm.
7. The application according to claim 1, characterized in that, The growth promotion is manifested in the increase of plant height, above-ground fresh weight, and below-ground fresh weight.
8. The application according to claim 1, characterized in that, The application can also upregulate lettuce defense-related genes. LsPPO3 and LsPPO4 The expression.
9. A method for improving the growth and insect resistance of lettuce, characterized in that, This includes the exogenous application of L-tryptophan to lettuce plants.
10. A lettuce cultivation composition, characterized in that, It contains an effective amount of L-tryptophan as an active ingredient to promote lettuce growth and enhance its insect resistance.