Entry Mode-Dependent Function of an Indole Glucosinolate Pathway in Arabidopsis for Nonhost Resistance against Anthracnose Pathogens
Entry Mode-Dependent Function of an Indole Glucosinolate Pathway in Arabidopsis for Nonhost Resistance against Anthracnose Pathogens
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DOI：
10.1105/tpc.110.074344
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发表时间：
2010-07-01
期刊：
影响因子：
11.6
通讯作者：
Takano, Yoshitaka
中科院分区：
文献类型：
--
作者：
Hiruma, Kei;Onozawa-Komori, Mariko;Takano, Yoshitaka
当面对不适应的真菌病原体时，拟南芥会产生非宿主抗性反应，这通常会导致早期致病步骤的终止。我们报告说，非适应性炭疽病真菌从事两种替代的进入模式在发病过程中的叶子：turgor-mediated黑附着胞下的入侵，和以前未发现的菌丝尖端为基础的条目（HTE）是独立的附着胞形成。HTE的频率受碳水化合物营养素的正调控，并且似乎受到真菌丝裂原活化蛋白激酶（MAPK）级联反应的组成性抑制。同样的MAPK级联反应对于附着胞的形成也是必不可少的。出乎意料的是，拟南芥吲哚芥子油苷途径限制进入的非适应性炭疽真菌只有当这些病原体采用HTE。拟南芥突变体的吲哚硫代葡萄糖苷的生物合成或代谢缺陷支持非适应炭疽gloeosporioides和炭疽orbiculare入侵后的增长开始。然而，炭疽菌附着胞形成的遗传破坏不允许HTE对宿主植物。因此，Colletotrichum appressoria在抑制入侵前植物防御中发挥关键作用，除了它们先前描述的在turgor-mediated植物细胞入侵中的作用。我们还表明，HTE是主要的形态发生反应的炭疽菌在伤口部位。这意味着存在一个真菌传感系统，以触发适当的形态发生反应，在发病过程中在伤口部位和完整的叶组织。
When faced with nonadapted fungal pathogens, Arabidopsis thaliana mounts nonhost resistance responses, which typically result in the termination of early pathogenesis steps. We report that nonadapted anthracnose fungi engage two alternative entry modes during pathogenesis on leaves: turgor-mediated invasion beneath melanized appressoria, and a previously undiscovered hyphal tip-based entry (HTE) that is independent of appressorium formation. The frequency of HTE is positively regulated by carbohydrate nutrients and appears to be subject to constitutive inhibition by the fungal mitogen-activated protein kinase (MAPK) cascade of MAPK ESSENTIAL FOR APPRESSORIUM FORMATION1. The same MAPK cascade is essential for appressorium formation. Unexpectedly, the Arabidopsis indole glucosinolate pathway restricts entry of the nonadapted anthracnose fungi only when these pathogens employ HTE. Arabidopsis mutants defective in indole glucosinolate biosynthesis or metabolism support the initiation of postinvasion growth of nonadapted Colletotrichum gloeosporioides and Colletotrichum orbiculare. However, genetic disruption of Colletotrichum appressorium formation does not permit HTE on host plants. Thus, Colletotrichum appressoria play a critical role in the suppression of preinvasion plant defenses, in addition to their previously described role in turgor-mediated plant cell invasion. We also show that HTE is the predominant morphogenetic response of Colletotrichum at wound sites. This implies the existence of a fungal sensing system to trigger appropriate morphogenetic responses during pathogenesis at wound sites and on intact leaf tissue.