Mol Plant Microbe Interact. 2014 Mar;27(3):236-43. doi: 10.1094/MPMI-07-13-0201-R.
Fungal cell-wall chitin is a well-recognized pathogen-associated molecular pattern. Recognition of chitin in plants by pattern recognition receptors activates pathogen-triggered immunity (PTI). In Arabidopsis, this process is mediated by a plasma membrane receptor kinase, CERK1, whereas in rice, a receptor-like protein, CEBiP, in addition to CERK1 is required. Secreted chitin-binding lysin motif (LysM) containing fungal effector proteins, such as Ecp6 from the biotrophic fungus Cladosporium fulvum, have been reported to interfere with PTI. Here, we identified wheat homologues of CERK1 and CEBiP and investigated their role in the interaction with the nonbiotrophic pathogen of wheat Mycosphaerella graminicola (synonym Zymoseptoria tritici). We show that silencing of either CERK1 or CEBiP in wheat, using Barley stripe mosaic virus-mediated virus-induced gene silencing, is sufficient in allowing leaf colonization by the normally nonpathogenic M. graminicola Mg3LysM (homologue of Ecp6) deletion mutant, while the Mg1LysM deletion mutant was fully pathogenic toward both silenced and wild-type wheat leaves. These data indicate that Mg3LysM is important for fungal evasion of PTI in wheat leaf tissue and that both CERK1 and CEBiP are required for activation of chitin-induced defenses, a feature conserved between rice and wheat, and perhaps, also in other cereal species.
真菌细胞壁几丁质是一种公认的病原体相关分子模式。植物中模式识别受体对几丁质的识别激活了病原体触发的免疫（PTI）。在拟南芥中，这个过程由质膜受体激酶 CERK1 介导，而在水稻中，除了 CERK1 之外，还需要受体样蛋白 CEBiP。已报道，分泌几丁质结合赖氨酸基序（LysM）的真菌效应蛋白，如生物营养型真菌匐枝根霉 Cladosporium fulvum 中的 Ecp6，会干扰 PTI。在这里，我们鉴定了小麦 CERK1 和 CEBiP 的同源物，并研究了它们在与非生物营养型小麦病原体禾谷丝核菌（同义词为玉蜀黍平脐蠕孢 Zymoseptoria tritici）相互作用中的作用。我们表明，使用大麦条纹花叶病毒介导的病毒诱导基因沉默，沉默小麦中的 CERK1 或 CEBiP 足以允许原本非致病性的 M. graminicola Mg3LysM（Ecp6 的同源物）缺失突变体在叶片上定殖，而 Mg1LysM 缺失突变体对沉默和野生型小麦叶片都是完全致病性的。这些数据表明，Mg3LysM 对于真菌逃避小麦叶片组织中的 PTI 很重要，并且 CERK1 和 CEBiP 对于激活几丁质诱导的防御都是必需的，这是水稻和小麦之间的共同特征，也许在其他谷类物种中也是如此。
