拟南芥茉莉酸途径调节植物对根结线虫的防御反应

JA Mediated Signaling Pathway Regulate Plant Defense Responses of Root Knot Nematode

对拟南芥根中的茉莉酸(Jasmonic acid,JA)生物合成和信号转导途径及JA对根结线虫发病机制所起的作用进行了研究。研究发现根结线虫的侵染显著诱导拟南芥根中JA和JA-异亮氨酸共轭物(JA-Ile)的合成,分别为AOS1、OPR3和JAR1基因调控。根结线虫在JA缺失突变体和JA-Ile缺失突变体(aos1、opr3、jar1)根中的生殖活性明显低于野生型,但是在缺失JA信号转导核心基因的突变体coi1和jin1的根中同野生型没有显著区别。使用外源JAIle可以使根结线虫在jar1根中的生殖能力恢复到在野生型根中的水平。这些结果证明,拟南芥根中JA的合成途径为根结线虫侵染所必需。

Nematode parasites achieve chronic infection by overcoming the innate immunity system of the hosts.In plants,the role of JA to innate immunity is well established in the leaves.The role of JA in defending against parasitic root knot nematode is largely unknown.Here,we showed the root knot nematode Meloidogyne incognita infection induced Allene Oxide Synthase1（ AOS1） and OPR3（ 12-oxo-Phytodienoic Acid Reductase 3） dependent JA and Jasmonate Resistant1（ JAR1） dependent JA-Ile biosynthesis.The nematode reproduction ability was significantly lower on the JA-Ile deficient roots（ aos1,opr3,jar1） than those of wild types.Two JA signal transduction mutants,the coronatine insensitive1（ coi1） and the JA insensitive1（ jin1）,showed wile type susceptibility to the nematode infection.The decreasing nematode reproduction ability on the roots of jar1,specifically missing JA-Ile,could be rescued by exogenous application of JA-Ile.JA synthesis pathway is important in prouss of the nematode infect Arabidopsis root.