Constitutive activation of AtMEK5,a MAPK kinase,induces salicylic acid- independent cell death in Arabidopsis thaliana  

作　　者：LIUHongxia WANGYing ZHOUTianhong SUNYujing LIUGuoqin RENDongtao 

机构地区：[1]StateKeyLaboratoryofPlantPhysiologyandBiochemistry,CollegeofBiologicalSciences,ChinaAgriculturalUniversity,Beijing100094,China

出　　处：《Chinese Science Bulletin》2004年第24期2594-2600,共7页

摘　　要：AtMEK5 DD is an active mutant of AtMEK5, a MAP kinase kinase in Arabidopsis. Induction of AtMEK5 DD expression in transgenic plants leads to activation of 44 and 48 kD MAPKs and causes a rapid cell death. To compare the cell death induced by the expression of AtMEK5 DD with the HR-cell death induced by avirulence pathogen infection, we analyzed the activation of downstream MAP Kinase and induction of PR genes expression in permanent transgenic Arabidopsis plants. In-gel kinase activity assay revealed that the infection of Pseudomonas syringae DC3000 harboring Avr Rpt2 gene also lead to activation of 44 and 48 kD MAPKs. PAL, PR1 and PR5 were strongly induced in plants undergo- ing HR-cell death caused by the infection of P. syringae DC3000, while only the expression of PR5 was strongly in- duced in transgenic plants expressing AtMEK5 DD protein. NahG protein in AtMEK5 ×NahG plants cannot suppress DD the cell death induced by AtMEK5 . And AtMEK5 DD DD pro- tein expressed AtMEK5 ×NahG plants showed no signifi- DD cant change in salicylic acid (SA) level. All these suggest that the cell death induced by the activation of AtMEK5 is sali- cylic acid-independent.AtMEK5 DD is an active mutant of AtMEK5, a MAP kinase kinase in Arabidopsis. Induction of AtMEK5 DD expression in transgenic plants leads to activation of 44 and 48 kD MAPKs and causes a rapid cell death. To compare the cell death induced by the expression of AtMEK5 DD with the HR-cell death induced by avirulence pathogen infection, we analyzed the activation of downstream MAP Kinase and induction of PR genes expression in permanent transgenic Arabidopsis plants. In-gel kinase activity assay revealed that the infection of Pseudomonas syringae DC3000 harboring Avr Rpt2 gene also lead to activation of 44 and 48 kD MAPKs. PAL, PR1 and PR5 were strongly induced in plants undergo- ing HR-cell death caused by the infection of P. syringae DC3000, while only the expression of PR5 was strongly in- duced in transgenic plants expressing AtMEK5 DD protein. NahG protein in AtMEK5 ×NahG plants cannot suppress DD the cell death induced by AtMEK5 . And AtMEK5 DD DD pro- tein expressed AtMEK5 ×NahG plants showed no signifi- DD cant change in salicylic acid (SA) level. All these suggest that the cell death induced by the activation of AtMEK5 is sali- cylic acid-independent.

关 键 词：AtMEK5 MAPK致活酶 水杨酸 细胞 病原体 植物 自我保护系统 

分 类 号：S432.1[农业科学—植物病理学] Q55[农业科学—农业昆虫与害虫防治]