2-undecanol for the prevention and treatment of mango anthracnose

Abstract

The application discloses application of 2-undecanol in prevention and treatment of mango anthracnose. In-vitro bacteriostasis tests prove that 2-undecanol has excellent inhibitory activity on Colletotrichum gloeosporioides: the bacteriostasis rate of 2-undecanol is 37.47% to 91.33% at a concentration of 5 to 3125 μL / L. In-vitro disease prevention tests show that the disease prevention effect of 2-undecanol is optimal at 250 μL / L, and the disease control effects on the 7th, 10th and 12th days of fumigation treatment are 43.45%, 60.67% and 74.07% respectively. The raw material is easy to obtain, the bacteriostasis and disease prevention effect is outstanding, and the 2-undecanol can be developed into a green prevention and control agent for mango anthracnose.

Description

Technical Field

[0001] This invention belongs to the field of plant protection, and specifically relates to the application of 2-undecyl alcohol in the prevention and control of mango anthracnose. Background Technology

[0002] This invention relates to 2-undecanol (methylnonylmethanol), with the molecular formula C1. 11 H 24O is a colorless to pale yellow oily liquid with a citrus aroma and some volatility. This compound is insoluble in water, miscible with most organic solvents, has a boiling point of 229–231°C, and is of low toxicity. 2-Undecyl alcohol is naturally found in various plants and microorganisms. Plant sources included hops (Li Feng, Liu Yumei. Gas chromatography-mass spectrometry analysis of volatile components of Magnum hops[J]. Food Science, 2012, 33(22): 259-263.), rue (Semerdjieva IB, Burducea M, Astatkie T, et al. Essential oil composition of Ruta graveolens L. Fruits and Hyssopus officinalis subsp. aristatus (Godr.) Nyman biomass as a function of hydrodistillation time[J]. Molecules, 2019, 24(22): 4047.), and taro pumpkin leaves (Li Junxing, Zhong Yujuan, Luo Jianning, et al. Analysis of aroma components and characteristics of taro pumpkin leaves based on headspace solid phase microextraction combined with gas chromatography-mass spectrometry[J]. Journal of Zhejiang University (Agricultural and Life Sciences Edition), 2019, 45(02):175-180.) as well as coconut meat, cheese and floral volatiles; microbial sources include Bacillus amyloliquefaciens (Yuan J, Raza W, Shen Q, et al. Antifungal activity of Bacillus amyloliquefaciens NJN-6 volatile compounds against Fusariumoxysporum f. sp. cubense[J]. Applied and environmental microbiology, 2012, 78(16): 5942-5944.), Bacillus subtilis (Kai M. Diversity and distribution of volatile secondary metabolites throughout Bacillus subtilisisolates[J]. Frontiers in Microbiology, 2020, 11: 559.), and Paenibacillus spp.(Yang F, Dai W, Xue H, et al. Efficacy of 2-undecanolproduced by Paenibacillus polymyxa KM2501-1 in controlling Meloidogyne incognita[J]. Microbiology Spectrum, 2025, 13(8): e03062-03024.) (Pseudomonas multivoransand Pseudomonas aeruginosa)(Forney F, Markovetz A.Oxidative degradation of methyl ketones II. Chemical pathway for degradationof 2-tridecanone by Pseudomonas multivorans and Pseudomonas aeruginosa[J].Journal of bacteriology, 1968, 96(4): 1055-1064 KL , Rasley A , Avila JR , et al. Metabolic profiling ofvolatile organic compounds (VOCs) emitted by the pathogens Francisellatularensis and Bacillus anthracis in liquid culture[J]. [ PubMed ] Yagi T, Kawaguchi M,Hatano T, et al. Formation of n-alkane-2-ones and n-alkane-2-ols fromtriglycerides by a black yeast, Aureobasidium[J]. Jfermentbioeng, 1991, 71(2): 93-99.)Saccharomyces cerevisiae(Jewison T, Knox C, Neveu V,et al.YMDB: the yeast metabolome database[J]. Nucleic acids research, 2012, 40(D1): D815-D820.). 2-Undecyl alcohol is characterized by its wide natural availability, unique aroma, volatility, and low toxicity, leading to its extensive applications. In the fragrance industry, it is used as a fixative or flavor compound; in agriculture, it is known as a plant growth regulator or a pheromone component of certain insects (such as whiteflies and beetles) for pest behavior regulation; and in the chemical industry, it is a key intermediate in the synthesis of plasticizers, surfactants, and other fine chemicals.

[0003] Mango (Mangifera indica L.) is a world-renowned tropical fruit, widely cultivated in tropical and subtropical regions around the world, and has important economic value. However, its production and storage have long been seriously threatened by mango anthracnose. The disease is mainly caused by the complex of *Colletotrichum gloeosporioides*, a species of fungus belonging to the Deuteromycetes (Tang, L., Qin, R., Huang, S., Chen, X., Guo, T., Hsiang, T., & Li, Q. (2024). Dimethyl trisulfide reduces postharvest anthracnose and enhances smango quality, and a potential molecular mechanism against *Colletotrichum gloeosporioides*. Pesticide Biochemistry and Physiology, 206, 106-174.). The pathogen has a latent infection characteristic, which can remain latent in the tissues of immature fruits and rapidly cause disease when the fruits mature or become senescent after harvest (Liu, Xiujuan; Yang, Yetong; Huang, Shengming. Effects of nutrients on latent infection of two anthracnose fungi [J]. Acta Mycologica Sinica, 1995, (1) 50-56.).This disease can occur throughout the entire growth period of mango and during post-harvest storage and transportation. During the flowering and young fruit stages, it causes flower and fruit drop (Lin Ya, Lei Yue, Lu Chongshan, et al. Research progress on major diseases and pests of mango [J]. Agricultural Science and Technology Communications, 2023, (07):147-152.). Mature fruits develop black sunken lesions, severely affecting the appearance and commercial value of the fruit (Su Chulian, Kang Hao, Mei Zhidong, et al. Analysis of the expression of pathogenic genes during the infection of mango anthracnose fungus [J]. Biotechnology Bulletin, 2018, 34(10): 182-186.). It can cause losses of 30-60% annually, with a maximum of 100% (Li QL, Bu JY, Shu J, Yu ZH, Tang LH, Guo TX, Mo JY, Luo SM, Solangi GS, Hsiang T. Colletotrichum species associated with mango in southern China. Scientific Reports 2019, 9:18891; Choudhary H, Dhar V, Dave P, et al. Postharvestanthracnose disease in mango (Mangifera indica L.) fruit: Sustainable alternatives for the control[J]. Crop Science, 2025, 65(3): e70064.), is currently an important limiting factor for increasing mango yield and improving quality.

[0004] Mango anthracnose is mainly caused by infection with Colletotrichum gloeosporioides and is a major disease during the planting and post-harvest storage of mangoes. It easily causes fruit rot, reduced yield, and lower commercial quality (Zhang He, Xu Chunqing, Jia Jing, et al. Indoor virulence determination of Colletotrichum gloeosporioides and Colletotrichum oxysporus in mangoes[J]. Jiangsu Agricultural Sciences, 2015, 43(08): 128-130.). Currently, production mainly relies on chemical fungicides for control, but long-term use easily leads to the development of drug resistance in pathogens (Yang Ye, He Shuhai, Zhang Shujuan, et al. Determination of resistance of Hainan mango anthracnose to carbendazim [J]. Journal of Tropical Crops, 2008, (01):73-77.). Simultaneously, problems such as pesticide residues, environmental pollution, and ecological damage exist (Pan Xiaowei, Dynamics and Risk Assessment of Difenoconazole Residue in Postharvest Mango [D]: Hainan University, 2014; Mo Jianyou, Integrated Control Technical Regulations for Mango Anthracnose [M].). Therefore, developing new green and efficient biological pesticides to replace or reduce the use of chemical pesticides has become an urgent need for the sustainable development of the industry. Summary of the Invention

[0005] The present invention aims to provide new plant protection applications for 2-undecyl alcohol, and to solve the technical defects of existing technologies such as poor efficacy, low safety and easy development of resistance.

[0006] The application of 2-undecyl alcohol in the prevention and control of mango anthracnose involves using 2-undecyl alcohol as the active ingredient and applying it to the target organism via fumigation to inhibit the growth of *A. mangoescarpium* and prevent mango anthracnose.

[0007] The air concentration of 2-undecyl alcohol used to inhibit the growth of *Mango colloid anthrax* is 5–3125 μL / L.

[0008] Preferably, the air concentration of the 2-undecyl alcohol is 125–3125 μL / L.

[0009] The host of mango anthracnose is mango.

[0010] The application described uses 2-undecyl alcohol to fumigate mangoes infected with plant pathogens after harvest to prevent mango anthracnose.

[0011] The air concentration of the 2-undecyl alcohol used is 50–250 μL / L.

[0012] Preferred concentration of 2-undecyl alcohol in the air is 250 μL / L.

[0013] This invention verifies its efficacy through fumigation treatment, including mycelial growth inhibition and live mango disease prevention experiments. Fumigation of *Amanita muscaria* effectively inhibits mycelial growth. Simultaneously, fumigation of mango fruit with 250 μL / L 2-undecyl alcohol at an air concentration significantly reduces the incidence of mango anthracnose, inhibits lesion expansion, and effectively alleviates the severity of mango anthracnose.

[0014] Compared with existing technologies, this invention has the following advantages: 1. Definite antibacterial and disease-preventing effects. This invention confirms that 2-undecyl alcohol has a significant inhibitory effect on *Amanita muscaria*, effectively inhibiting both the vegetative growth and reproductive infection processes of the pathogen. The in vivo disease prevention effect is stable, effectively controlling the occurrence and spread of mango anthracnose; 2. Green and safe, with no residue risk. Compound 2-undecyl alcohol is a low-toxicity, easily degradable substance. Its application in mango production will not cause excessive pesticide residues. It is safe for humans and animals, ecologically friendly, and meets the requirements of green fruit production; 3. Wide applicability and easy promotion. The raw materials are readily available, and the physicochemical properties are stable. The formulation process and application are simple, suitable for field disease prevention and post-harvest preservation. It can be used alone or in combination, showing good prospects for industrial application. Attached Figure Description

[0015] Figure 1 The colony morphology of *Colletotrichum gloeosporioides* after treatment with different concentrations of 2-undecyl alcohol.

[0016] Figure 2 The efficacy of 2-undecyl alcohol at different air concentrations against postharvest mango anthracnose was investigated. Detailed Implementation

[0017] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art, and the raw materials used are all commercially available products.

[0018] The following strains are all preserved in the applicant's laboratory and can be publicly distributed.

[0019] Example 1: Determination of the antibacterial effect of volatile substances on *Colletotrichum mangosum* anthracnose.

[0020] The tested *Colletotrichum candida* bacteria were cultured on PDA medium for 5 days. 6 mm diameter bacterial blocks were punched from the edge of the colonies using a puncher, and then inoculated onto the center of the PDA plate with the hyphae facing down. Filter paper discs were placed in blank culture dishes, and the compounds of various concentrations were added dropwise onto the filter paper. The PDA plate was then inverted onto the filter paper plate, and the joint between the upper and lower plates was sealed with sealing film. The plates were then incubated in the dark at 25°C. When the control plate (without the drug) reached the edge, the colony diameter was measured using the cross-hatching method, and the inhibition rate was calculated. Inhibition rate (%) = (Control colony diameter - Treated colony diameter) / (Control colony diameter - Mycelial cake diameter) × 100

[0021] The petri dish is 1.3 cm thick, the PDA medium is 0.5 cm thick, and the petri dish diameter is 8.6 cm. Therefore, the total volume of the two dishes stacked together is (8.6 / 2). 2 *3.14*(1.3*2-0.5)=0.12 L, therefore, the amounts of 2-undecyl alcohol added for each air concentration of 5 µL / L, 25 µL / L, 125 µL / L, 625 µL / L, and 3125 µL / L are 0.6 μL, 3 μL, 15 μL, 75 μL, and 375 μL, respectively.

[0022] Within the concentration range of 5–3125 μL / L, the antibacterial rate of 2-undecyl alcohol continuously increases with increasing concentration. At 5 μL / L, the antibacterial rate is 37.47%; at 25 μL / L, it rises to 60.51%; and at 125 μL / L, it reaches 88.67%. Further increases in concentration to 625 and 31 μL / L result in slight improvements in antibacterial effect, with the highest concentration of 3125 μL / L achieving an antibacterial rate of 91.33%. Subsequent increases in concentration show a slower increase in antibacterial effect, indicating that the antibacterial effect is approaching saturation.

[0023] Table 1. Inhibition rate (%) of different concentrations of 2-undecyl alcohol against *Colletotrichum mangosum* anthracnose.

[0024]

[0025] Table 2. Virulence regression equations and EC50 values ​​of compounds against *Colletotrichum mangosum*. 50 and EC 90 value

[0026]

[0027] Example 2: Determination of the control effect of fumigation treatment with the volatile substance 2-undecyl alcohol on mango anthracnose.

[0028] Because mango anthracnose has a latent infection characteristic, it does not show symptoms when immature, but only after harvest and ripening will it show anthracnose symptoms. To observe the therapeutic effect of 2-undecyl alcohol, fresh mango fruits of similar size and maturity were selected, and 8 mango fruits were placed in a 5 L plastic box, with 3 replicates for each treatment. A petri dish lined with filter paper was placed in the center of the plastic box, and the corresponding volume of compound was dropped onto the filter paper. The plastic box was then covered, and the edges were sealed with sealing film to prevent gas from escaping. The box was placed in a 25°C environment for fumigation treatment, and the effect was observed after 7, 10, and 12 days. The disease index was investigated, and the control efficacy was calculated.

[0029] Grading standards:

[0030] Level 0: Asymptomatic;

[0031] Grade 1: The area of ​​lesions accounts for less than 5% of the fruit area;

[0032] Grade 3: Lesions cover 6-15% of the fruit area;

[0033] Grade 5: Lesions cover 16-25% of the fruit area;

[0034] Grade 7: Lesions cover 26-50% of the fruit area;

[0035] Level 9: The area of ​​diseased spots accounts for more than 51% of the fruit area.

[0036] The calculation method is as follows:

[0037]

[0038] The significance of the differences was analyzed using Duncan's new multiple range method in DPS 7.05 statistical analysis software. In the analysis results, the same lowercase letters indicate that the differences are not significant at the 5% level.

[0039] The plastic container has a volume of 5 L. For an air concentration of 1000 μL / L, add 5 mL of 2-undecanol. For 250 μL / L, add 1.25 mL. For 50 μL / L, add 0.25 mL. For 10 μL / L, add 0.05 mL.

[0040] The results showed that 2-undecyl alcohol at 250 μL / L had the best disease control effect on days 7, 10, and 12, with control efficacies of 43.45%, 60.67%, and 74.07%, respectively. At 1000 μL / L, 2-undecyl alcohol caused mild phytotoxicity symptoms on day 7 and significant phytotoxicity symptoms on days 10 and 12. This concentration is not suitable for fumigation treatment of mangoes (Table 3). Figure 2 ).

[0041] Table 3. Efficacy of 2-Undecanoic acid against postharvest anthrax

[0042]

Claims

1. 2-Undecyl alcohol is used to inhibit plant pathogens, specifically Colletotrichum gloeosporioides. 2-Undecyl alcohol is used as the active ingredient in fumigation to inhibit the growth of Colletotrichum gloeosporioides and control mango anthracnose.

2. In the application according to claim 1, the air concentration of 2-undecyl alcohol used to inhibit the growth of *Mango colloides* is 5–3125 μL / L.

3. In the application according to claim 2, the air concentration of the 2-undecyl alcohol is 125–3125 μL / L.

4. In the application according to claim 1, the host of the plant pathogen is mango.

5. According to the application described in claim 4, 2-undecyl alcohol is used to fumigate mangoes infected with plant pathogens after harvest to prevent mango anthracnose.

6. In the application according to claim 5, the air concentration of the 2-undecyl alcohol is 50 to 250 μL / L.

7. In the application according to claim 6, the air concentration of the 2-undecyl alcohol is 250 μL / L.

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