南方根结线虫拮抗链霉菌的筛选和鉴定

通过生物测定和温室防病试验 ,对分离自江苏省南京、淮阴和上海三地 3 0份土样的 3 44株放线菌菌株进行筛选 ,得到了 1株对南方根结线虫有较高生物活性的链霉菌菌株LH1 2 1。其培养滤液在离体条件下对南方根结线虫二龄幼虫有较强的触杀作用 ,4h内击倒率达 1 0 0 % ,1 2h内致死率达 1 0 0 % ;番茄植株上的活体防病试验表明 ,2ml/株培养滤液对根结和卵块形成的抑制率分别为52 .8%和 63 .5%。遗传稳定性试验表明LH1 2 1菌株能稳定产生杀线活性物质。LH1 2 1培养滤液主要通过直接触杀二龄幼虫或干扰其侵入植株而达到防治目的。根据形态、培养和生理生化特性的分析 ,将LH1 2 1鉴定为玫瑰暗黄链霉菌

Screening of Antagonistic Streptomycete from Soils Against Meloidogyne incognita

actinomycete isolates were gained from 30 soil samples in Nanjing, Huaiying, Shanghai. Their antagonism against Meloidogyne incognita was tested in vitro and in greenhouse. Culture filtrate of one strain (LH121) could knock-down 100% of the J2 individuals of M. incognita within 4h and killed 100% within 12h. In greenhouse experiments, 2ml culture filtrate per tomato plant could inhibit 52.8% gall formation and 63.5% egg mass formation. LH121 could produce nematicidal compounds stably after continuously transferation. Further study showed that LH121 was mainly through directly killing J2 or disturbing infection process to control nematodes population, it had no effect on development of the nematode within host plant. LH121 was identified as Streptomyces reseofulvus based on its morphology, culture characters as well as physiological and biochemical characteristics.