生防真菌对苜蓿根腐病的抗病机理研究

Alfalfa root rot is one of the diseases, which is widely distributed and with serious harm in alfalfa production. It also has become an important barrier to high-yield, high-quality, and yield-stability of alfalfa. In face of a series of issues, such as the pollution caused by the chemical treatments, drug resistance for pathogenic bacterium and the increased the economic cost, biocontrol technology has been a hot area of research in the field with significant implication for practitioners. In order to explore and discover new microbial resources, which can apply to the biocontrol of the disease, applicants select the strains which can produce antagonism to the pathogens of alfalfa root rot from different rhizosphere soils. The applicants also measure the it’s growth inhibition rate, colonization ability, and investigae the influences on microflora of soil and biocontrol effect. Explorition of its antagonistic mechanism has been conducted further. The purpose of the research is to screen out biocontrol strains which can be widely-applied with good control efficiency and colonization ability, which will benefit the future further researches in preventing bacterial inoculum with providing strains options and empirical evidences. Pratically, the research may also provide feasible basis for the production of organic Alfalfa in the industry, which may contribute to reduction of the ecological protection, and sustainable development of the farming and animal husbandry in Western Development Program.

苜蓿根腐病是苜蓿生产中分布广、危害严重的病害之一，已成为影响苜蓿高产、优质、稳产的重要限制因素。针对化学防治易引起诸如环境污染、病原菌产生抗药性以及增加经济成本等问题,通过生防手段对其进行防治已成为该领域的研究热点，对于苜蓿生产具有重大意义。为了探索和发掘新的微生物资源，使其应用于苜蓿根腐病的生物防治，申请者拟从苜蓿根际土壤及根系内生真菌中分离筛选出对苜蓿根腐病病原菌能够产生抗病作用的菌株，对其生长抑制率、定殖能力、土壤微生物区系的影响以及生防效果进行测定，并在此基础上对其抗病机理进行探索，以期能够筛选出抑菌范围广、防治效果好、定殖能力强的生防菌株，为今后进一步研发生防菌肥提供菌种和科学依据，为生产苜蓿绿色或有机产品提供保障，为降低西部大开发工程中的环境污染，保护西部生态环境做出贡献，为保障农牧业可持续发展开辟新的途径。

苜蓿根腐病是苜蓿生产中分布广、危害严重的病害之一，已成为影响苜蓿高产、优质、稳产的重要限制因素。针对化学防治易引起诸如环境污染、病原菌产生抗药性以及增加经济成本等问题,通过生防手段对其进行防治已成为该领域的研究热点，对于苜蓿生产具有重大意义。为了探索和发掘新的微生物资源，使其应用于苜蓿根腐病的生物防治，本项目对来自不同品种、生境的苜蓿根际土壤和根系表面分离和纯化中的真菌中筛选出了2株抑菌能力较强的菌株ZY56和GY37，并通过形态学和分子鉴定，最终确定ZY56为哈茨木霉Trichoderma harzianum； GY37为康宁木霉Trichoderma koningi。通过对峙培养、生防菌株孢子悬浮液及无菌发酵滤液处理病原菌的方法分别对2株生防菌株对4种引起苜蓿根腐病的病原菌（苜蓿尖孢镰刀菌（F. oxysporum）、燕麦镰刀菌（F. averceum）、腐皮镰刀菌(F. solani)、半裸镰刀菌(F. semitectum)）的抑菌作用进行了研究，并对生防真菌对苜蓿根腐病的温室盆栽防效、在土壤中的定殖能力及其对微生物区系的影响进行了测定。进一步对生防真菌的抗病机理进行了研究，包括生防真菌对苜蓿根腐病病原菌菌丝形态的影响及其对苜蓿防御酶活性的影响等，为今后进一步研发生防菌肥提供菌种和科学依据，为生产苜蓿绿色或有机产品提供保障，为降低西部大开发工程中的环境污染，保护西部生态环境做出贡献，为保障农牧业可持续发展开辟新的途径。