Conservation of Chitin-Induced MAPK Signaling Pathways in Rice and Arabidopsis
Conservation of Chitin-Induced MAPK Signaling Pathways in Rice and Arabidopsis
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DOI：
10.1093/pcp/pcx042
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发表时间：
2017-06-01
影响因子：
4.9
通讯作者：
Kawasaki, Tsutomu
中科院分区：
文献类型：
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作者：
Yamada, Kenta;Yamaguchi, Koji;Kawasaki, Tsutomu
模式识别受体（PRR）对包括几丁质在内的微生物相关分子模式（MAMP）的感知迅速诱导丝裂原激活蛋白激酶（MAPK）级联的激活。然而，PRR 如何将免疫信号传递至 MAPK 级联尚不清楚。最近，据报道，拟南芥受体样细胞质激酶 PBL27 通过几丁质信号通路中 AtMAPKKK5 的磷酸化来激活 MAPK。在这项研究中，我们发现 OsRLCK185（PBL27 的水稻直系同源物）以与水稻中 PBL27 类似的方式调节几丁质诱导的 MAPK 激活。在几丁质感知后，OsRLCK185 被 OsCERK1（几丁质受体复合物的一个组成部分）磷酸化。在酵母双杂交检测中，OsRLCK185 与 AtMAPKKK5 的水稻直系同源 OsMAPKKK11 和 OsMAPKKK18 相互作用。 OsMAPKKK11 和 OsMAPKKK18 的沉默显着降低了几丁质诱导的 OsMPK3 和 OsMPK6 的激活。水稻细胞中OsMAPKKK18的表达水平远高于OsMAPKKK11，这与Osmapkkk11单突变不影响MAPK激活的事实相一致。这一结果表明，在几丁质诱导的 OsMPK3 和 OsMPK6 激活中，OsMAPKKK18 比 OsMAPKKK11 发挥更重要的作用。双分子荧光互补（BiFC）实验表明OsRLCK185与OsMAPKKK18在植物质膜上发生相互作用。体外磷酸化实验表明，OsRLCK185 直接磷酸化 OsMAPKKK18。此外，OsMAPKKK18 与 MAPKK OsMKK4（OsMPK3/6 的上游组件）相互作用。这些结果表明 OsRLCK185 将几丁质受体连接到由 OsMAPKKK18-OsMKK4-OsMPK3/6 组成的 MAPK 级联。我们的数据表明，水稻和拟南芥中几丁质诱导的 MAPK 激活受到共同同源元件的调节。
Perception of microbe-associated molecular patterns (MAMPs) including chitin by pattern recognition receptors (PRRs) rapidly induces activation of mitogen-activated protein kinase (MAPK) cascades. However, how PRRs transmit immune signals to the MAPK cascade is largely unknown. Recently, Arabidopsis receptor-like cytoplasmic kinase PBL27 has been reported to activate MAPKs through phosphorylation of AtMAPKKK5 in the chitin signaling pathway. In this study, we found that OsRLCK185, a rice ortholog of PBL27, regulates chitin-induced MAPK activation in a similar fashion to PBL27 in rice. Upon chitin perception, OsRLCK185 is phosphorylated by OsCERK1, a component of the chitin receptor complex. OsRLCK185 interacted with OsMAPKKK11 and OsMAPKKK18, rice orthologs of AtMAPKKK5, in yeast two-hybrid assays. Silencing of both OsMAPKKK11 and OsMAPKKK18 significantly reduced chitin-induced activation of OsMPK3 and OsMPK6. Expression levels of OsMAPKKK18 were much higher than that of OsMAPKKK11 in rice cells, which was consistent with the fact that the Osmapkkk11 single mutation did not affect MAPK activation. This result suggested that OsMAPKKK18 plays a more important role than OsMAPKKK11 in the chitin-induced activation of OsMPK3 and OsMPK6. The bimolecular fluorescence complementation (BiFC) experiment indicated that OsRLCK185 interacted with OsMAPKKK18 at the plasma membrane in planta. In vitro phosphorylation experiments showed that OsRLCK185 directly phosphorylates OsMAPKKK18. Furthermore, OsMAPKKK18 interacted with the MAPKK OsMKK4, the upstream component of OsMPK3/6. These results suggested that OsRLCK185 connects the chitin receptor to the MAPK cascade consisting of OsMAPKKK18-OsMKK4-OsMPK3/6. Our data revealed that chitin-induced MAPK activation in rice and Arabidopsis is regulated by common homologous elements.