title: Overexpression of AtCHX24, a member of the cation/H⁺ exchangers, accelerates leaf senescence in Arabidopsis thaliana.
abstract: Leaf senescence, the final stage of leaf development, occurs in an age-dependent manner but can be finely regulated by other developmental and environmental factors. Despite the discovery of many genes involved in leaf senescence, the molecular genetic mechanisms of leaf senescence are still unclear. In this study, an activation-tagging based suppressor screen was performed to identify Arabidopsis genes that could suppress the delayed leaf senescence phenotypes of oresara9-1 (ore9-1) when overexpressed. The suppressor1 of ore9 dominant (sor1-D) was caused by the overexpression of AtCHX24, a putative cation/H(+) exchanger. The sor1-D mutation suppressed the phenotypes of ore9 in age-dependent and dark-induced senescence. Furthermore, the sor1-D mutation restored the delayed senescence phenotypes of ore1 and ore3. The sor1-D mutant also exhibited increased sensitivity to pH changes during dark-induced leaf senescence. Collectively, overexpression of AtCHX24 results in accelerated leaf senescence and these results suggest that AtCHX24 plays an important role in regulating leaf senescence.
authors.affiliation: Department of Biological Science, Chungnam National University, Daejeon 305-764, Republic of Korea.
authors.forename: Yoonkang
authors.initials: Y
authors.lastname: Hur
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Kim
authors.forename: Dong-Joon
authors.initials: DJ
authors.lastname: Lee
authors.forename: Kyung Min
authors.initials: KM
authors.lastname: Chung
authors.forename: Hye Ryun
authors.initials: HR
authors.lastname: Woo
mesh_terms: D017920:Antiporters / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D004269:DNA, Bacterial / Q000235:genetics; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D016153:Genes, Suppressor / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D009154:Mutation; D010641:Phenotype; D017440:Photoperiod; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D018749:RNA, Plant / Q000032:analysis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism / Q000502:physiology
chemical_list: D017920:Antiporters; D029681:Arabidopsis Proteins; C575164:CHX24 protein, Arabidopsis; D002352:Carrier Proteins; D004269:DNA, Bacterial; C435920:MAX2 protein, Arabidopsis; C538850:ORE1 protein, Arabidopsis; D018749:RNA, Plant; C036483:T-DNA; D014157:Transcription Factors