title: A MAPK cascade downstream of ERECTA receptor-like protein kinase regulates Arabidopsis inflorescence architecture by promoting localized cell proliferation.
abstract: Spatiotemporal-specific cell proliferation and cell differentiation are critical to the formation of normal tissues, organs, and organisms. The highly coordinated cell differentiation and proliferation events illustrate the importance of cell-cell communication during growth and development. In Arabidopsis thaliana, ERECTA (ER), a receptor-like protein kinase, plays important roles in promoting localized cell proliferation, which determines inflorescence architecture, organ shape, and size. However, the downstream signaling components remain unidentified. Here, we report a mitogen-activated protein kinase (MAPK; or MPK) cascade that functions downstream of ER in regulating localized cell proliferation. Similar to an er mutant, loss of function of MPK3/MPK6 or their upstream MAPK kinases (MAPKKs; or MKKs), MKK4/MKK5, resulted in shortened pedicels and clustered inflorescences. Epistasis analysis demonstrated that the gain of function of MKK4 and MKK5 transgenes could rescue the loss-of-function er mutant phenotype at both morphological and cellular levels, suggesting that the MPK3/MPK6 cascade functions downstream of the ER receptor. Furthermore, YODA (YDA), a MAPKK kinase, was shown to be upstream of MKK4/MKK5 and downstream of ER in regulating inflorescence architecture based on both gain- and loss-of-function data. Taken together, these results suggest that the YDA-MKK4/MKK5-MPK3/MPK6 cascade functions downstream of the ER receptor in regulating localized cell proliferation, which further shapes the morphology of plant organs.
authors.affiliation: Division of Biochemistry, Interdisciplinary Plant Group, Bond Life Sciences Center, University of Missouri, Columbia, Missouri 65211, USA.
authors.forename: Xiangzong
authors.initials: X
authors.lastname: Meng
authors.forename: Huachun
authors.initials: H
authors.lastname: Wang
authors.forename: Yunxia
authors.initials: Y
authors.lastname: He
authors.forename: Yidong
authors.initials: Y
authors.lastname: Liu
authors.forename: John C
authors.initials: JC
authors.lastname: Walker
authors.forename: Keiko U
authors.initials: KU
authors.lastname: Torii
authors.forename: Shuqun
authors.initials: S
authors.lastname: Zhang
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000166:cytology / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D011956:Receptors, Cell Surface; C457763:ER protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; C458516:AtMPK3 protein, Arabidopsis; C436293:MPK6 protein, Arabidopsis; D020928:Mitogen-Activated Protein Kinases; D020930:MAP Kinase Kinase Kinases; C481302:YODA protein, Arabidopsis; C519871:MKK4 protein, Arabidopsis; C519872:MKK5 protein, Arabidopsis; D020929:Mitogen-Activated Protein Kinase Kinases