Msp40 effector of root-knot nematode manipulates plant immunity to facilitate parasitism.
Msp40 effector of root-knot nematode manipulates plant immunity to facilitate parasitism.
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根结线虫的Msp40效应子操纵植物免疫以促进寄生
DOI：
10.1038/srep19443
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发表时间：
2016-01-22
影响因子：
4.6
通讯作者：
Jian H
中科院分区：
文献类型：
--
作者：
Niu J;Liu P;Liu Q;Chen C;Guo Q;Yin J;Yang G;Jian H
根结线虫(RKN)是侵袭植物根部并与寄主建立长期亲密关系的专性生物营养寄生虫。线虫分泌物，其中一些具有免疫抑制活性，在成功的寄生中起着至关重要的作用；然而，它们的作用机制在很大程度上仍然不清楚。在这里，我们发现从南方根结线虫克隆的RKN特异性基因MiMsp40只在食道腺腹下细胞中表达，并在寄生早期强烈上调。高表达MiMsp40的拟南芥分裂株比野生型植物更容易受到线虫侵染。相反，宿主衍生的MiMsp40RNAi抑制了线虫的寄生和/或繁殖。此外，MiMsp40在植物中的过表达抑制了愈伤组织的沉积和细菌激发子elf18触发的免疫标记基因的表达。MiMsp40的瞬时表达阻止了Bax引发的防御相关的程序性细胞死亡。共渗入实验表明，MiMsp40还能抑制由MAPK级联或ETI同源激发子R3a/AVR3a引发的宏观细胞死亡。综上所述，这些结果表明，MiMsp40是一种新的根结线虫特异性效应器，通过线虫的早期寄生阶段注入植物细胞，并在抑制PTI和/或ETI信号以促进RKN寄生方面发挥作用。
Root-knot nematodes (RKNs) are obligate biotrophic parasites that invade plant roots and engage in prolonged and intimate relationships with their hosts. Nematode secretions, some of which have immunosuppressing activity, play essential roles in successful parasitism; however, their mechanisms of action remain largely unknown. Here, we show that the RKN-specific geneMiMsp40, cloned fromMeloidogyne incognita, is expressed exclusively in subventral oesophageal gland cells and is strongly upregulated during early parasitic stages.Arabidopsisplants overexpressingMiMsp40were more susceptible to nematode infection than were wild type plants. Conversely, the host-derivedMiMsp40RNAi suppressed nematode parasitism and/or reproduction. Moreover, overexpression ofMiMsp40in plants suppressed the deposition of callose and the expression of marker genes for bacterial elicitor elf18-triggered immunity. Transient expression ofMiMsp40prevented Bax-triggered defence-related programmed cell death. Co-agroinfiltration assays indicated that MiMsp40 also suppressed macroscopic cell death triggered by MAPK cascades or by the ETI cognate elicitors R3a/Avr3a. Together, these results demonstrate that MiMsp40 is a novelMeloidogyne-specific effector that is injected into plant cells by early parasitic stages of the nematode and that plays a role in suppressing PTI and/or ETI signals to facilitate RKN parasitism.