title: The Nicotiana benthamiana mitogen-activated protein kinase cascade and WRKY transcription factor participate in Nep1(Mo)-triggered plant responses.
abstract: Many bacterial, fungal, and oomycete species secrete necrosis and ethylene-inducing peptide 1 (Nep1)-like proteins (NLP) that trigger programmed cell death (PCD) and innate immune responses in dicotyledonous plants. However, how NLP induce such immune responses is not understood. Here, we show that silencing of the MAPKKKα-MEK2-WIPK mitogen-activated protein kinase (MAPK) cascade through virus-induced gene silencing compromises hydrogen peroxide accumulation and PCD induced by Nep1(Mo) from Magnaporthe oryzae. WIPK interacts with NbWRKY2, a transcription factor in Nicotiana benthamiana, in vitro and in vivo, suggesting an effector pathway that mediates Nep1(Mo)-induced cell death. Unexpectedly, salicylic acid-induced protein kinase (SIPK)- and NbWRKY2-silenced plants showed impaired Nep1(Mo)-induced stomatal closure, decreased Nep1(Mo)-promoted nitric oxide (NO) production in guard cells, and a reduction in Nep1(Mo)-induced resistance against Phytophthora nicotianae. Expression studies by real-time polymerase chain reaction suggested that the MEK2-WIPK-NbWRKY2 pathway regulated Nep1(Mo)triggered NO accumulation could be partly dependent on nitrate reductase, which was implicated in NO synthesis. Taken together, these studies demonstrate that the MAPK cascade is involved in Nep1(Mo)-triggered plant responses and MAPK signaling associated with PCD exhibits shared and distinct components with that for stomatal closure.
authors: Department of Plant Pathology, Nanjing Agricultural University, Nanjing, China.
authors: Huajian
authors: H
authors: Zhang
authors: Deqing
authors: D
authors: Li
authors: Meifang
authors: M
authors: Wang
authors: Jiewen
authors: J
authors: Liu
authors: Wenjun
authors: W
authors: Teng
authors: Baoping
authors: B
authors: Cheng
authors: Qian
authors: Q
authors: Huang
authors: Min
authors: M
authors: Wang
authors: Wenwen
authors: W
authors: Song
authors: Suomeng
authors: S
authors: Dong
authors: Xiaobo
authors: X
authors: Zheng
authors: Zhengguang
authors: Z
authors: Zhang
mesh_terms: D002118:Calcium / Q000032:analysis / Q000378:metabolism; D016923:Cell Death / Q000235:genetics; D005656:Fungal Proteins / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D006706:Homeostasis; D006861:Hydrogen Peroxide / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000235:genetics*; D020082:Magnaporthe / Q000502:physiology; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D009569:Nitric Oxide / Q000032:analysis / Q000378:metabolism; D010838:Phytophthora / Q000502:physiology; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D057865:Plant Immunity / Q000235:genetics*; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D054046:Plant Stomata / Q000166:cytology / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D030821:Plants, Genetically Modified; D036226:Seedlings / Q000166:cytology / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D014026:Nicotiana / Q000166:cytology / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D010940:Plant Proteins; D014157:Transcription Factors; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D020928:Mitogen-Activated Protein Kinases; C106405:SA-induced protein kinase; D002118:Calcium