The MAPK Kinase Kinase GmMEKK1 Regulates Cell Death and Defense Responses
| Autor: | Wen-Li Qiu, Yafei Shi, Paul A. Nakata, Chi Zhang, Zhen-Chao Li, Hui-Yang Xu, Dongtao Ren, Jian-Zhong Liu, Bo Wang, Duroy A. Navarre, Michelle A. Graham, Steven A. Whitham, Juan Xu, E. J. Braun, Xu-Xu Jiang, Zhi-Rong Wang, Ninghui Cheng, Yu Mei, Sheng-Nan Tian, Sen Li |
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| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Hypersensitive response MAPK/ERK pathway Programmed cell death Cell signaling Physiology Arabidopsis MAP Kinase Kinase Kinase 1 Plant Science Biology 03 medical and health sciences Tobacco Genetics Gene silencing Kinase activity Disease Resistance Plant Diseases Plant Proteins Mitogen-Activated Protein Kinase Kinases Peronospora Cell Death Kinase fungi food and beverages Articles biology.organism_classification Cell biology 030104 developmental biology Soybeans |
| Zdroj: | Plant Physiology. 178:907-922 |
| ISSN: | 1532-2548 0032-0889 |
| Popis: | MAPK signaling pathways play critical roles in plant immunity. Here, we silenced multiple genes encoding MAPKs using virus-induced gene silencing mediated by Bean pod mottle virus to identify MAPK genes involved in soybean (Glycine max) immunity. Surprisingly, a strong hypersensitive response (HR) cell death was observed when soybean MAPK KINASE KINASE1 (GmMEKK1), a homolog of Arabidopsis (Arabidopsis thaliana) MEKK1, was silenced. The HR was accompanied by the overaccumulation of defense signaling molecules, salicylic acid (SA) and hydrogen peroxide. Genes involved in primary metabolism, translation/transcription, photosynthesis, and growth/development were down-regulated in GmMEKK1-silenced plants, while the expression of defense-related genes was activated. Accordingly, GmMEKK1-silenced plants were more resistant to downy mildew (Peronospora manshurica) and Soybean mosaic virus compared with control plants. Silencing GmMEKK1 reduced the activation of GmMPK6 but enhanced the activation of GmMPK3 in response to flg22 peptide. Unlike Arabidopsis MPK4, GmMPK4 was not activated by either flg22 or SA. Interestingly, transient overexpression of GmMEKK1 in Nicotiana benthamiana also induced HR. Our results indicate that GmMEKK1 plays both positive and negative roles in immunity and appears to differentially activate downstream MPKs by promoting GmMPK6 activation but suppressing GmMPK3 activation in response to flg22. The involvement of GmMPK4 kinase activity in cell death and in flg22- or SA-triggered defense responses in soybean requires further investigation. |
| Databáze: | OpenAIRE |
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