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南方根结线虫生防菌X

来源：花匠小妙招时间：2025-01-05 15:00

摘要：

南方根结线虫是设施蔬菜上的重要植物病原物，但目前缺乏安全高效的生物防治措施。本研究从根结线虫罹病土壤中分离到一株生防菌X-20，其发酵液对南方根结线虫二龄幼虫校正死亡率达100%。通过形态学、生理生化特征和分子生物学方法将菌株X-20鉴定为荧光假单胞菌Pseudomonas fluorescens。菌株X-20发酵液处理南方根结线虫时，当处理浓度1 mg/mL，虫体出现扭曲、僵直变化，内部组织分解；处理1 h后，虫体波动频率降幅47.26%、头部摆动频率波动性变化、虫体弯曲频率成S型变化；处理24 h后，二龄幼虫的体长减少4.68%，口针增加7.64%，透明尾长增加83.90%；J2虫体体液出现外渗，且电导率随着处理浓度的增大和时间延长而增加；发酵液甲醇提取物1 mg/mL处理虫体，6 h后糖含量比对照增加39.10%，甘油含量比对照高出66.67%，可溶性蛋白含量降低55.73%。由此可见，荧光假单胞菌X-20菌株代谢产物通过破坏根结线虫体壁及虫体内部结构，引起虫体液渗漏，扰乱虫体内糖类、脂类、蛋白类代谢，造成虫体死亡。

关键词: 荧光假单胞菌, 代谢产物, 南方根结线虫, 防治效果, 生防机理

Abstract:

Meloidogyne incognita is a major pathogen that affects vegetable crops, and currently, there are limited safe and efficient biological control options available. In this study, strain X-20 ed from soil where root-knot nematodes were present. When tested against second-stage juveniles (J2) of M. incognita, strain X-20 exhibited a mortality rate of up to 100% after 24 and 48 hours. The strain X-20 was identified as Pseudomonas fluorescens through various methods, including morphological, physiological, biochemical and molecular biological analysis. When 1 mg/mL fermentation broth of strain X-20 was used to treat J2 of M. incognita, the nematode body showed twisted and stiff changes, and the internal tissue decomposed. After 1 hour of treatment, the fluctuation frequency of the body decreased by 47.26%, the swing frequency of head and the bending frequency of the body also changed. After 24 hours of treatment, the body length of M. incognita J2 decreased 4.68%, while the stylet length and the hyaline tail length of M. incognita J2 increased by 7.64% and 83.9%, respectively. Meanwhile, the body fluids of M. incognita J2 leaked, and its conductivity increased with the increase of treatment concentration and time. After six hours treatment with 1 mg/mL methanol extract from fermentation broth, the sugar and glycerol content of J2 body increased by 39.10%, 66.67%, respectively; While the soluble protein content of J2 body 55.73% decreased compared to the control. In conclusion, the metabolites produced by strain X-20 were found to cause body fluid leakage, disrupt the body wall and internal structure of root-knot nematodes, and affect the metabolism of sugars, lipids, and proteins, ultimately leading to the death of M. incognita.

Key words: Pseudomonas fluorescens, metabolite, Meloidogyne incognita; control efficacy, biocontrol mechanism

中图分类号:

S476

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所属分类：花卉