丛枝菌根菌诱导植物抗病的内在机制

应用菌根真菌诱导植物抗病性是近年化学生态学和病害生物防治研究的热点．研究表明，丛枝菌根真菌(AMF)对土传病原物具有一定拮抗或抑制作用，能提高植物对土传病害的抗／耐病性．在菌根根际，各种菌群不断产生相互作用，AMF在其中起着抑制病原菌、促进有益菌生长的作用，可与其他桔抗菌结合，用做生防菌．AMF提高植物抗病性的机制还有这样几种假设：(1)植物营养得到改善；(2)竞争作用；(3)根系形态结构改变；(4)根际微生物区系变化；(5)诱导抗性及诱导系统抗性，即AMF侵染植物根系后，诱导植物体内酚酸类代谢产物增加，使植物产生局部或系统防御反应．深人研究AMF提高植物抗病性的机制，有助于正确理解菌根的抗病作用，使其能尽快地成为植物病害生物防治中的一种新方法，在生态农业中发挥作用。

Mechanisms of plant disease resistance induced by arbuscular mycorrhizal fungi

In recent years,the induced disease resistance of plant by Arbuscular Mycorrhizal Fungi (AMF) has become a hot spot in chemo ecological study and in biocontrol of plant disease. There were many reports indicating that AMF had antagonistic function to soilborne disease pathogen,or could suppress the growth of pathogen,and increase the resistance or tolerance of mycorrhizal plants to soilborne disease. In mycorrhizosphere,there are interactions among microbial community,in which,AMF could suppress the growth of pathogen and promote the growth of beneficial microbe. Thus,AMF may use as biocontrol fungi with other antagonism microbe. There were several hypotheses about the mechanisms of the increased resistance in mycorrhizal plants:(1) improvement of plant nutrient status; (2) competition;(3)changed roots morphology and structure ; (4) changed microbial flora in rhizosphere; (5)induced resistance or systematic resistance in plant. After colonized by AMF,phenolic compounds accumulate in plant,and local defense response or systemic defense response occurs. It is necessary to do intensive research on the mechanisms of increased resistance in mycorrhizal plants,because it may help us understand the function of disease resistance of mycorrhiza correctly,and let us use AMF as a new biocontrol method to control soilborne disease in eco agriculture in the near future.