南方农业学报2025，Vol.56Issue(4)：1005-1016,12.DOI:10.3969/j.issn.2095-1191.2025.04.001
抗水稻纹枯病的昆虫病原线虫共生菌分离、鉴定及发酵条件优化
Isolation,identification and fermentation condition optimiza-tion of symbiotic bacteria from entomopathogenic nematodes resistant to rice sheath blight
摘要
Abstract
[Objective]The strains of symbiotic bacteria from entomopathogenic nematodes were isolated from Chilo suppressalis individuals,the strain with high antibacterial activity against rice sheath blight was screened to further enrich the resources of entomopathogenic nematode symbiotic bacteria,which could provide theoretical basis for the application of entomopathogenic nematode symbiotic bacteria in the control of Chilo suppressalis and rice sheath blight.[Method]Strains of symbiotic bacteria from entomopathogenic nematodes were isolated by hemolymph separation method from the dead Chilo suppressalis individuals infected with Steinernema.NBTA culture morphology combined with 16S rRNA am-plification sequencing was used to identify the symbiotic species of entomopathogenic nematodes.Plate culture method was used to determine the inhibitory rate of symbiotic bacteria from entomopathogenic nematodes against rice sheath blight strain,and strain with high antibacterial activity against rice sheath blight was screened.The whole genome of strain with high antibacterial activity was sequenced,and the growth curve of strain with high antibacterial activity was obtained by liquid culture.The carbon source,nitrogen source and inorganic salt of the strain liquid fermentation medium of strain with high antibacterial activity were optimized by single factor test and orthogonal test,and the optimal condi-tions for liquid fermentation,inoculation amount,fermentation temperature and rotation speed were screened.[Result]Five strains of symbiotic bacteria from entomopathogenic nematodes were isolated and identified as Xenorhabdus nema-tophila strains.NBTA culture characteristics showed that 1 strain of the 5 entomopathogenic nematode symbiotic bacteria was secondary bacteria,and the other 4 strains were primary bacteria.The primary strain HN04 had the highest inhibitory rate against rice sheath blight(73.62％),and the secondary strain HN01 had the lowest inhibitory rate(55.29％),strain HN01 was significantly different from that of the 4 primary strains(P<0.05).The strain HN04 with the highest inhibitory rate was selected for follow-up study.The results of whole genome sequencing showed that strain HN04 consisted of a ring chromosome with a size of 7998302 bp and an average GC content of 44.03％.The logarithmic growth period of strain HN04 was 4-28 h,the stable period was 28-52 h,and it entered the decline period after 52 h.Single factor and or-thogonal experiment optimized the liquid fermentation conditions of strain HN04,and the medium combination was 2.0％maltose,2.0％peptone,1.0％NaCl.The main order of influence of each factor on the concentration of bacteria in the fer-mentation solution was nitrogen source factor>inorganic salt factor>carbon source factor.The optimal liquid fermenta-tion conditions were 30％-40％of liquid in triangular bottle,4％-12％of inoculum,fermentation temperature 28-32 ℃ and rotation speed 180 r/min.[Conclusion]Xenorhabdus nematophila strains are isolated from Chilo suppressalis.The pri-mary Xenorhabdus nematophila bacteria HN04 has the highest antibacterial activity against rice sheath blight.The opti-mized fermentation scheme can be used to rapidly culture HN04 strain suspensions in large quantities.HN04 has potential application value in controlling Chilo suppressalis and rice sheath blight.关键词
昆虫病原线虫共生菌/嗜线虫致病杆菌/二化螟/水稻纹枯病/抑菌活性/液体发酵条件优化Key words
symbiotic bacteria from entomopathogenic nematodes/Xenorhabdus nematophila/Chilo suppressalis/rice sheath blight/antibacterial activity/liquid fermentation condition optimization分类
农业科技引用本文复制引用
邵晨霞,刘洋,朱华珺,刘絮宁,杨祎,唐少军,任锐,颜莲莲,鲁湘,许隽..抗水稻纹枯病的昆虫病原线虫共生菌分离、鉴定及发酵条件优化[J].南方农业学报,2025,56(4):1005-1016,12.基金项目
国家重点研发计划项目(2021YFD1401100) （2021YFD1401100）
湖南省重点研发计划项目(2023NK2016) （2023NK2016）
湖南省科技创新计划项目(2024RC8167) National Key Research and Development Program of China(2021YFD1401100) （2024RC8167）
Hunan Key Re-search and Development Plan Project(2023NK2016) （2023NK2016）
Hunan Science and Technology Innovation Project(2024RC8167) （2024RC8167）
