title: Activation of MKK9-MPK3/MPK6 enhances phosphate acquisition in Arabidopsis thaliana.
abstract: Despite the abundance of phosphorus in soil, very little is available as phosphate (Pi) for plants. Plants often experience low Pi (LP) stress. Intensive studies have been conducted to reveal the mechanism used by plants to deal with LP; however, Pi sensing and signal transduction pathways are not fully understood. Using in-gel kinase assays, we determined the activities of MPK3 and MPK6 in Arabidopsis thaliana seedlings under both LP and Pi-sufficient (Murashige and Skoog, MS) conditions. Using MKK9 mutant transgenic and crossed mutants, we analyzed the functions of MPK3 and MPK6 in regulating Pi responses of seedlings. The regulation of Pi responses by downstream components of MKK9-MPK3/MPK6 was also screened. LP treatment activated MPK3 and MPK6. Under both LP and MS conditions, mpk3 and mpk6 seedlings took up and accumulated less Pi than the wild-type; activation of MKK9-MPK3/MPK6 in transgenic seedlings induced the transcription of Pi acquisition-related genes and enhanced Pi uptake and accumulation, whereas its activation suppressed the transcription of anthocyanin biosynthetic genes and anthocyanin accumulation; WRKY75 was downstream of MKK9-MPK3/MPK6 when regulating the accumulation of Pi and anthocyanin, and the transcription of Pi acquisition-related and anthocyanin biosynthetic genes. These results suggest that the MKK9-MPK3/MPK6 cascade is part of the Pi signaling pathway in plants.
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Lei
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
authors.forename: Yifang
authors.initials: Y
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
authors.forename: Hailian
authors.initials: H
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
authors.forename: Dongtao
authors.initials: D
authors.lastname: Ren
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D004789:Enzyme Activation / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D050505:Mutant Proteins / Q000378:metabolism; D010710:Phosphates / Q000172:deficiency / Q000378:metabolism* / Q000494:pharmacology; D030821:Plants, Genetically Modified; D036226:Seedlings / Q000201:enzymology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D050505:Mutant Proteins; D010710:Phosphates; C458516:AtMPK3 protein, Arabidopsis; C436293:MPK6 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases; C527379:MKK9 protein, Arabidopsis; D020929:Mitogen-Activated Protein Kinase Kinases
keywords: Arabidopsis thaliana; MKK9; MPK3; MPK6; Pi responses; phosphate; signal transduction pathway