Na Li1, Zeyu Yang1, Juan Li1, Wenya Xie1, Xiaofeng Qin1, Yuanrong Kang1, Qinglu Zhang1, Xianghua Li1, Jinghua Xiao1, Haigang Ma2, Shiping Wang3. 1. National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China. 2. National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China. mhg@mail.hzau.edu.cn. 3. National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, 430070, China. swang@mail.hzau.edu.cn.
Abstract
BACKGROUND: The plant-specific valine-glutamine (VQ) protein family with the conserved motif FxxxVQxLTG reportedly functions with the mitogen-activated protein kinase (MAPK) in plant immunity. However, the roles of VQ proteins in MAPK-mediated resistance to disease in rice remain largely unknown. RESULTS: In this study, two rice VQ proteins OsVQ14 and OsVQ32 were newly identified to function as the signaling components of a MAPK cascade, OsMPKK6-OsMPK4, to regulate rice resistance to Xanthomonas oryzae pv. oryzae (Xoo). Both OsVQ14 and OsVQ32 positively regulated rice resistance to Xoo. In vitro and in vivo studies revealed that OsVQ14 and OsVQ32 physically interacted with and were phosphorylated by OsMPK4. OsMPK4 was highly phosphorylated in transgenic plants overexpressing OsMPKK6, which showed enhanced resistance to Xoo. Meanwhile, phosphorylated OsVQ14 and OsVQ32 were also markedly accumulated in OsMPKK6-overexpressing transgenic plants. CONCLUSIONS: We discovered that OsVQ14 and OsVQ32 functioned as substrates of the OsMPKK6-OsMPK4 cascade to enhance rice resistance to Xoo, thereby defining a more complete signal transduction pathway for induced defenses.
BACKGROUND: The plant-specific valine-glutamine (VQ) protein family with the conserved motif FxxxVQxLTG reportedly functions with the mitogen-activated protein kinase (MAPK) in plant immunity. However, the roles of VQ proteins in MAPK-mediated resistance to disease in rice remain largely unknown. RESULTS: In this study, two rice VQ proteins OsVQ14 and OsVQ32 were newly identified to function as the signaling components of a MAPK cascade, OsMPKK6-OsMPK4, to regulate rice resistance to Xanthomonas oryzae pv. oryzae (Xoo). Both OsVQ14 and OsVQ32 positively regulated rice resistance to Xoo. In vitro and in vivo studies revealed that OsVQ14 and OsVQ32 physically interacted with and were phosphorylated by OsMPK4. OsMPK4 was highly phosphorylated in transgenic plants overexpressing OsMPKK6, which showed enhanced resistance to Xoo. Meanwhile, phosphorylated OsVQ14 and OsVQ32 were also markedly accumulated in OsMPKK6-overexpressing transgenic plants. CONCLUSIONS: We discovered that OsVQ14 and OsVQ32 functioned as substrates of the OsMPKK6-OsMPK4 cascade to enhance rice resistance to Xoo, thereby defining a more complete signal transduction pathway for induced defenses.
Entities:
Keywords:
Bacterial blight; MAPK; Oryza sativa; Phosphorylation; VQ protein
Authors: Erik Andreasson; Thomas Jenkins; Peter Brodersen; Stephan Thorgrimsen; Nikolaj H T Petersen; Shijiang Zhu; Jin-Long Qiu; Pernille Micheelsen; Anne Rocher; Morten Petersen; Mari-Anne Newman; Henrik Bjørn Nielsen; Heribert Hirt; Imre Somssich; Ole Mattsson; John Mundy Journal: EMBO J Date: 2005-06-30 Impact factor: 11.598