Regulation of cotton (Gossypium hirsutum) drought responses by mitogen-activated protein (MAP) kinase cascade-mediated phosphorylation of GhWRKY59

• Published in: The New phytologist Vol. 215; no. 4; pp. 1462 - 1475
• Main Authors: Li, Fangjun, Li, Maoying, Wang, Ping, Cox, Kevin L., Duan, Liusheng, Dever, Jane K., Shan, Libo, Li, Zhaohu, He, Ping
• Format: Journal Article
• Language: English
• Published: England New Phytologist Trust 01.09.2017; Wiley Subscription Services, Inc
• Subjects: Abscisic acid; Adaptation, Physiological; Arabidopsis - genetics; Boxes; Control theory; Cotton; Dehydration; dehydration‐responsive element‐binding protein (DREB); Drought; drought stress; Droughts; Feedback; Feedback loops; Gene Expression Regulation, Plant; Gene Silencing; genetic analysis; Genomes; Gossypium - enzymology; Gossypium - genetics; Gossypium - physiology; Gossypium hirsutum; Hormones; Identification; Kinases; Limiting factors; loss-of-function mutation; MAP kinase; mitogen-activated protein kinase; Mitogen-Activated Protein Kinases - metabolism; mitogen‐activated protein (MAP) kinase cascade; Phosphorylation; Plant growth substances; Plant hormones; Plant Proteins - metabolism; Plant Viruses - physiology; Plants, Genetically Modified; Positive feedback; Profiling; Protein kinase; Proteins; Sequence Analysis, RNA; Serine; stress response; Stresses; Transcription; Transcription factors; transcriptomics; Tungsten; Viruses; Water shortages; water stress; WRKY transcription factor; cotton; mitogen-activated protein (MAP) kinase cascade; drought stress; phosphorylation; WRKY transcription factor; dehydration-responsive element-binding protein (DREB)
• DOI: 10.1111/nph.14680
• ISSN: 0028-646X; 1469-8137

Drought is a key limiting factor for cotton (Gossypium spp.) production, as more than half of the global cotton supply is grown in regions with high water shortage. However, the underlying mechanism of the response of cotton to drought stress remains elusive. By combining genome-wide transcriptome profiling and a loss-of-function screen using virus-induced gene silencing, we identified Gossypium hirsutum GhWRKY59 as an important transcription factor that regulates the drought stress response in cotton. Biochemical and genetic analyses revealed a drought stress-activated mitogen-activated protein (MAP) kinase cascade consisting of GhMAP3K15–Mitogen-activated Protein Kinase Kinase 4 (GhMKK4)–Mitogen-activated Protein Kinase 6 (GhMPK6) that directly phosphorylates GhWRKY59 at residue serine 221. Interestingly, GhWRKY59 is required for dehydration-induced expression of GhMAPK3K15, constituting a positive feedback loop of GhWRKY59-regulated MAP kinase activation in response to drought stress. Moreover, GhWRKY59 directly binds to the W-boxes of DEHYDRATION-RESPONSIVE ELEMENT-BINDING PROTEIN 2 (GhDREB2), which encodes a dehydration-inducible transcription factor regulating the plant hormone abscisic acid (ABA)-independent drought response. Our study identified a complete MAP kinase cascade that phosphorylates and activates a key WRKY transcription factor, and elucidated a regulatory module, consisting of GhMAP3K15-GhMKK4-GhMPK6-GhWRKY59-GhDREB2, that is involved in controlling the cotton drought response.