Quantitative Phosphoproteomic and Metabolomic Analyses Reveal GmMYB173 Optimizes Flavonoid Metabolism in Soybean under Salt Stress

作者：Erxu Pi, Chengmin Zhu, Wei Fan, Yingying Huang, Liqun Qu, Yangyang Li, Qinyi Zhao, Feng Ding, Lijuan Qiu, Huizhong Wang, B. W. Poovaiah, Liqun Du · 发表于：Molecular & Cellular Proteomics · 年份：2018 · DOI：10.1074/mcp.ra117.000417 · 被引用次数：105 · 研究领域：GABA and Rice Research、Plant Gene Expression Analysis、Plant Stress Responses and Tolerance

Salinity causes osmotic stress to crops and limits their productivity. To understand the mechanism underlying soybean salt tolerance, proteomics approach was used to identify phosphoproteins altered by NaCl treatment. Results revealed that 412 of the 4698 quantitatively analyzed phosphopeptides were significantly up-regulated on salt treatment, including a phosphopeptide covering the serine 59 in the transcription factor GmMYB173. Our data showed that GmMYB173 is one of the three MYB proteins differentially phosphorylated on salt treatment, and a substrate of the casein kinase-II. MYB recognition sites exist in the promoter of flavonoid synthase gene GmCHS5 and one was found to mediate its recognition by GmMYB173, an event facilitated by phosphorylation. Because GmCHS5 catalyzes the synthesis of chalcone, flavonoids derived from chalcone were monitored using metabolomics approach. Results revealed that 24 flavonoids of 6745 metabolites were significantly up-regulated after salt treatment. We further compared the salt tolerance and flavonoid accumulation in soybean transgenic roots expressing the 35 S promoter driven cds and RNAi constructs of GmMYB173 and GmCHS5 , as well as phospho-mimic ( GmMYB173 S59D ) and phospho-ablative ( GmMYB173 S59A ) mutants of GmMYB173 . Overexpression of GmMYB173 S59D and GmCHS5 resulted in the highest increase in salt tolerance and accumulation of cyaniding-3-arabinoside chloride, a dihydroxy B-ring flavonoid. The dihydroxy B-ring flavonoids are...