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南方根结线虫生防菌YB

花匠小妙招
2025-01-05 14:50

摘要： 南方根结线虫是一种全球性的植物寄生线虫，严重时会导致植株生长不良甚至死亡。为了挖掘南方根结线虫病的高效生防菌株，利用平板稀释法从严重发生根结线虫病的番茄根结中分离出24株细菌，并根据不同菌株的培养液对南方根结线虫的致死活性及其盆栽防治效果筛选生防菌。结果显示菌株YB-1503培养液对根结线虫的二龄幼虫校正死亡率最高，处理48 h时达70.0%，对番茄根结线虫病盆栽防治效果最好，为65.8%，同时促进番茄植株的生长。通过形态学、生理生化特征和分子生物学方法将菌株YB-1503鉴定为坚强芽胞杆菌Bacillus firmus。此外，菌株YB-1503发酵滤液能够显著降低南方根结线虫的过氧化氢酶、羧酸脂酶和乙酰胆碱脂酶的活性，并降低线虫的抗氧化能力，增加线虫活性氧含量，从而导致线虫死亡。由此可见，菌株YB-1503具有较大的开发利用潜力。

关键词: 南方根结线虫, 坚强芽胞杆菌, 生物防治, 生防机理

Abstract: Root-knot nematode Meloidogyne incognita is a global plant parasitic nematode that can cause poor plant growth and even death in severe cases. In order to excavate biocontrol strains against root-knot nematode with high efficiency, 24 strains of bacteria were isolated from the tomato root infected with root-knot nematode by plate dilution method. To screen high efficiency biocontrol strains, the lethal activity of cultures to second-stage juveniles (J2s) and their control effect in the greenhouse were determined. The results showed that strain YB-1503 had the highest adjusted mortality of J2s, reaching 70.0% at 48 h. Greenhouse experiment demonstrated that treatments with cultures of strain YB-1503 reduced root-knot index by 65.8%, along with increased plant growth. Strain YB-1503 was identified as Bacillus firmus by morphological，physiological and molecular biological methods. In addition, fermentation filtrates of strain YB-1503 could significantly reduce the activities of catalase, carboxylesterase and acetylcholinesterase of J2s. The content of reactive oxygen species (ROS) of J2s was also increased after being treated by fermentation filtrate of strain YB-1503, resulting in the death of nematode. Thus, YB-1503 strain has great potential for further development and utilization.

Key words: Meloidogyne incognita, Bacillus firmus, biological control, biocontrol mechanism

中图分类号:

S476