J Integr Plant Biol ›› 2016, Vol. 58 ›› Issue (8): 724-736.DOI: 10.1111/jipb.12465

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Expression of the inactive ZmMEK1 induces salicylic acid accumulation and salicylic acid-dependent leaf senescence

Yuan Li, Ying Chang, Chongchong Zhao, Hailian Yang and Dongtao Ren*   

  • 收稿日期:2015-08-17 接受日期:2016-01-28 出版日期:2016-01-29 发布日期:2016-01-29

Expression of the inactive ZmMEK1 induces salicylic acid accumulation and salicylic acid-dependent leaf senescence

Yuan Li, Ying Chang, Chongchong Zhao, Hailian Yang and Dongtao Ren*   

  1. State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
  • Received:2015-08-17 Accepted:2016-01-28 Online:2016-01-29 Published:2016-01-29
  • About author:*Correspondence: E-mail: ren@cau.edu.cn

摘要: MAPK signaling cascades play important roles in regulating leaf senescence. We demonstrate that inactive ZmMEK1 induces SA accumulation and SA-dependent leaf senescence in its transgenic Arabidopsis plants. ZmMEK1 activates ZmSIMK1 and Arabidopsis MPK4 in vitro. Blockage of MAPK signaling increases endogenous SA accumulation in maize leaves.

Abstract:

Leaf senescence is the final leaf developmental process that is regulated by both intracellular factors and environmental conditions. The mitogen-activated protein kinase (MAPK) signaling cascades have been shown to play important roles in regulating leaf senescence; however, the component(s) downstream of the MAPK cascades in regulating leaf senescence are not fully understood. Here we showed that the transcriptions of ZmMEK1, ZmSIMK1, and ZmMPK3 were induced during dark-induced maize leaf senescence. Furthermore, in-gel kinase analysis revealed the 42 kDa MAPK was activated. ZmMEK1 interacted with ZmSIMK1 in yeast and maize mesophyll protoplasts and ZmSIMK1 was activated by ZmMEK1 in vitro. Expression of a dominant negative mutant of ZmMEK1 in Arabidopsis transgenic plants induced salicylic acid (SA) accumulation and SA-dependent leaf senescence. ZmMEK1 interacted with Arabidopsis MPK4 in yeast and activated MPK4 in vitro. SA treatment accelerated dark-induced maize leaf senescence. Moreover, blockage of MAPK signaling increased endogenous SA accumulation in maize leaves. These findings suggest that ZmMEK1-ZmSIMK1 cascade and its modulating SA levels play important roles in regulating leaf senescence.

Key words: Leaf senescence, MAPK cascade, salicylic acid

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