title: Arabidopsis histidine-containing phosphotransfer factor 4 (AHP4) negatively regulates secondary wall thickening of the anther endothecium during flowering.
abstract: Cytokinins are essential hormones in plant development. Arabidopsis histidine-containing phosphotransfer proteins (AHPs) are mediators in a multistep phosphorelay pathway for cytokinin signaling. The exact role of AHP4 has not been elucidated. In this study, we demonstrated young flower-specific expression of AHP4, and compared AHP4-overexpressing (Ox) trangenic Arabidopsis lines and an ahp4 knock-out line. AHP4-Ox plants had reduced fertility due to a lack of secondary cell wall thickening in the anther endothecium and inhibition of IRREGURAR XYLEMs (IRXs) expression in young flowers. Conversely, ahp4 anthers had more lignified anther walls than the wild type, and increased IRXs expression. Our study indicates that AHP4 negatively regulates thickening of the secondary cell wall of the anther endothecium, and provides new insight into the role of cytokinins in formation of secondary cell walls via the action of AHP4.
authors.affiliation: School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
authors.forename: Kwang Wook
authors.initials: KW
authors.lastname: Jung
authors.forename: Seung-Ick
authors.initials: SI
authors.lastname: Oh
authors.forename: Yun Young
authors.initials: YY
authors.lastname: Kim
authors.forename: Kyoung Shin
authors.initials: KS
authors.lastname: Yoo
authors.forename: Mei Hua
authors.initials: MH
authors.lastname: Cui
authors.forename: Jeong Sheop
authors.initials: JS
authors.lastname: Shin
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000378:metabolism*; D005298:Fertility; D035264:Flowers / Q000166:cytology / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D010641:Phenotype; D010770:Phosphotransferases / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D012333:RNA, Messenger; C530434:Ahp4 protein, Arabidopsis; D010770:Phosphotransferases