The BRI1-Associated Kinase 1, BAK1, Has a Brassinolide-Independent Role in Plant Cell-Death Control

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• 作者：Birgit Kemmerling ; Anne Schwedt ; Patricia Rodriguez ; Sara Mazzotta ; Markus Frank ; Synan Abu Qamar ; Tesfaye Mengiste ; Shigeyuki Betsuyaku ; Jane E. Parker ; Carsten Mü ; ssig ; Bart P.H.J. Thomma ; Cathe
• 关键词：CELLCYCLE
• 刊名：Current Biology
• 出版年：2007
• 出版时间：3 July 2007
• 年：2007
• 卷：17
• 期：13
• 页码：1116-1122
• 全文大小：1046 K

文摘

Programmed cell death (PCD) is a common host response to microbial infection [1], [2] and [3]. In plants, PCD is associated with immunity to biotrophic pathogens, but it can also promote disease upon infection by necrotrophic pathogens [4]. Therefore, plant cell-suicide programs must be strictly controlled. Here we demonstrate that the Arabidopsis thaliana Brassinosteroid Insensitive 1 (BRI1)-associated receptor Kinase 1 (BAK1), which operates as a coreceptor of BRI1 in brassinolide (BL)-dependent plant development, also regulates the containment of microbial infection-induced cell death. BAK1-deficient plants develop spreading necrosis upon infection. This is accompanied by production of reactive oxygen intermediates and results in enhanced susceptibility to necrotrophic fungal pathogens. The exogenous application of BL rescues growth defects of bak1 mutants but fails to restore immunity to fungal infection. Moreover, BL-insensitive and -deficient mutants do not exhibit spreading necrosis or enhanced susceptibility to fungal infections. Together, these findings suggest that plant steroid-hormone signaling is dispensable for the containment of infection-induced PCD. We propose a novel, BL-independent function of BAK1 in plant cell-death control that is distinct from its BL-dependent role in plant development.