title: MAP Kinase PrMPK9-1 Contributes to the Self-Incompatibility Response.
abstract: Mitogen-activated protein kinases (MAPKs) form important signaling modules for a variety of cellular responses in eukaryotic cells. In plants, MAPKs play key roles in growth and development as well as in immunity/stress responses. Pollen-pistil interactions are critical early events regulating pollination and fertilization and involve many signaling events. Self-incompatibility (SI) is an important mechanism to prevent self-fertilization and inbreeding in higher plants and also is known to utilize signaling to achieve incompatible pollen rejection. Although several pollen-expressed MAPKs exist, very little is known about their function. We previously identified a pollen-expressed MAPK (p56) fromPapaver rhoeasthat was rapidly activated during SI; several studies implicated its role in signaling to SI-induced programmed cell death involving a DEVDase. However, to date, the identity of the MAPK involved has been unknown. Here, we have identified and cloned a pollen-expressedP. rhoeasthreonine-aspartate-tyrosine (TDY) MAPK,PrMPK9-1Rather few data relating to the function of TDY MAPKs in plants currently exist. We provide evidence thatPrMPK9-1has a cell type-specific function, with a distinct role fromAtMPK9To our knowledge, this is the first study implicating a function for a TDY MAPK in pollen. We show that PrMPK9-1 corresponds to p56 and demonstrate that it is functionally involved in mediating SI inP. rhoeaspollen: PrMPK9-1 is a key regulator for SI in pollen and acts upstream of programmed cell death involving actin and activation of a DEVDase. Our study provides an important advance in elucidating functional roles for this class of MAPKs.
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: Lijun
authors.initials: L
authors.lastname: Chai
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Tudor
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: Natalie S
authors.identifier: http://orcid.org/0000-0002-3187-2130
authors.initials: NS
authors.lastname: Poulter
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: Katie A
authors.identifier: http://orcid.org/0000-0001-6513-856X
authors.initials: KA
authors.lastname: Wilkins
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: Deborah J
authors.identifier: http://orcid.org/0000-0002-6122-3377
authors.initials: DJ
authors.lastname: Eaves
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: F Christopher H
authors.identifier: http://orcid.org/0000-0003-3507-722X
authors.initials: FCH
authors.lastname: Franklin
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom v.e.franklin-tong@bham.ac.uk.
authors.forename: Vernonica E
authors.identifier: http://orcid.org/0000-0003-1782-8413
authors.initials: VE
authors.lastname: Franklin-Tong
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D017360:Arabidopsis / Q000201:enzymology; D053148:Caspase 3 / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010207:Papaver / Q000201:enzymology* / Q000502:physiology*; D010447:Peptide Hydrolases / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism*; D053205:Pollen Tube / Q000187:drug effects / Q000254:growth & development; D021381:Protein Transport / Q000187:drug effects; D060436:Self-Incompatibility in Flowering Plants / Q000187:drug effects / Q000502:physiology*
chemical_list: D016376:Oligonucleotides, Antisense; D010750:Phosphoproteins; D010940:Plant Proteins; D020928:Mitogen-Activated Protein Kinases; D010447:Peptide Hydrolases; D053148:Caspase 3; C108711:DEVDase