少孢节丛孢对土壤细菌的化学防御机制

项目名称： 少孢节丛孢对土壤细菌的化学防御机制

项目编号： No.30870083

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 生物科学

项目作者： 牛雪梅

作者单位： 云南大学

项目金额： 30万元

中文摘要： 捕食线虫真菌对调节土壤中线虫的种群动态起到重要作用，是生物防治线虫危害的主要途径，但由于土壤抑菌作用的存在，使其防治效果不稳定而得不到有效推广应用。前期发现捕食线虫真菌在受到部分土壤细菌诱导时会产生防御反应（生成捕食器），而目前为止国内外对捕食线虫真菌的防御机制的研究尚未见报道。本项目拟以模式菌少孢节丛孢为出发菌，用不同土壤细菌（前期从强抑菌土壤中筛选到的优势种群假单胞菌和芽孢杆菌属）的代谢产物诱导使其产生防御反应，利用GC-MS和HPLC-MS检测分析其受到不同诱导后所产生的防御性次生代谢产物，并对这些成分进行分离和结构鉴定，测试主要防御成分抗相应土壤细菌的活性，寻找其防御规律，进一步探讨主要防御成分的生物合成途径，揭示其化学防御机制，为提高线虫生物防治的效率提供科学依据和参考价值，并可望发现具有应用前景的天然活性物质。

中文关键词： 捕食线虫真菌；少孢节丛孢；防御机制；次生代谢产物；土壤细菌诱导

英文摘要： Nematode-trapping fungi, which play key roles in regulating the dynamic populations of nematodes in soil, have been regarded as one of major strategies to biologically control nematode damage. However, it is hard to effectually apply them as biocontrol agents in field due to fungistatic effect from bacteria in soil. Our previous study displayed that nematode-trapping fungi could change their morphology, one of the defensive mechanisms, under the contact with soil bacteria, and the knowledge of the defensive mechanisms of the special type of fungi still remained unknown. We sought to obtain clues with respect to chemical defensive mechanism of one nematode-trapping fungus A. oligospora by checking the metabolic profilings with the analysis of HPLC-MS and GC-MS of this fungus cultivated under the contact with soil bacteria in different media, which imitate environmental conditions including nutrient poor and nutrient rich. We would like to find some biological chemicals involved in the defensive mechanoisms of A. oligospora, and to provide insights into microbial ecology that might also extend to mechanisms of fungal pathogenesis. Further study on the biosynthesis of these bioactive metabolites could be carries out and their potential applied function could be deeply evaluated. Our study would help to understand how to improve the efficiency of nematode-trapping fungi as biological agents applied in the field.

英文关键词： nematode-trapping fungus; Arthrobotrys oligospora; chemical defense; soil bacteria