番茄根结内生真菌诱导植株对南方根结线虫的抗性研究

Induced Systemic Resistance by Tomato Endophytic Fungi to Root Knot Nematode

为探明天津地区番茄主要种植区根结内生真菌的群落多样性并筛选具有杀线虫活性的菌株,笔者采集天津市各区番茄根结线虫病样,通过组织分离方法分离根结内生真菌并进行分子生物学鉴定。通过测定菌株发酵液对南方根结线虫二龄幼虫(J2)的致死作用,以及菌株在番茄根结形成的抑制作用来分析其抗性机制。结果显示:内生真菌主要为镰刀菌属Fusarium真菌,占比58%。内生真菌的杀线虫活性测定显示:枝顶孢霉Acremonium implicatum、A. sclerotigenum、毛壳菌Chaetomium sp.,拟青霉Purpureocillium sp.对根结线虫二龄幼虫具有较强的致死活性,处理48 h后,死亡率70%以上。内生真菌诱导番茄抗性结果显示:枝孢霉A. implicatum诱导番茄产生对根结线虫入侵的抗性最强,入侵率降低48.96%;其次为A. sclerotigenum,入侵率降低34.48%;Chaetomium sp.和Purpureocillium sp.入侵率较低,分别为17.17%和25.10%。综上,内生真菌A. implicatum及A. sclerotigenum能够通过毒杀J2及提高番茄抗性来防治根结线虫。

In order to explore the diversity of endophytic fungi community in tomato in Tianjin and screen the strains with nematicidal activity, we collected infected tomato plants from different districts in Tianjin. By tissue separation and molecular biology methods, endophytic fungi were isolated and identified. The resistance mechanism was analyzed by nematicidal bioassay of the fungi’s culturefiltrateson Juveniles(J2) of Meloidogyne incognita and the inhibitory effect of the strain on the formation of tomato root knot. The results showed that the main endophytic fungi were Fusarium fungi, accounting for 58%.The nematocidal activity of endophytic fungi was determined, the A. clerotigenum, A. clerotigenum, Chaetomium sp., and Purpureocillium sp.had obviously lethal activity against J2, and the mortality rate was more than 70% after 48 h treatment. The endophytic fungi induced tomato resistance results showed that A. implicatum induced tomato resistance to root-knot nematode invasion was the strongest, and the invasion rate decreased by 48.96%. The invasion rate of A. clerotigenum was decreased by 34.48%. Chaetomium sp. and Purpureocillium sp. the invasion rates were 17.17% and 25.10%, respectively. In conclusion, endophytic fungi A. implicatum and A. sclerotigenum could control the root knot nematode by poisoning J2 and improving the tomato resistance.