title: OsCHX14 is Involved in the K+ Homeostasis in Rice (Oryza sativa) Flowers.
abstract: Previously we showed in the osjar1 mutants that the lodicule senescence which controls the closing of rice flowers was delayed. This resulted in florets staying open longer when compared with the wild type. The gene OsJAR1 is silenced in osjar1 mutants and is a key member of the jasmonic acid (JA) signaling pathway. We found that K concentrations in lodicules and flowers of osjar1-2 were significantly elevated compared with the wild type, indicating that K+homeostasis may play a role in regulating the closure of rice flowers. The cation/H+exchanger (CHX) family from rice was screened for potential K+transporters involved as many members of this family in Arabidopsis were exclusively or preferentially expressed in flowers. Expression profiling confirmed that among 17 CHX genes in rice, OsCHX14 was the only member that showed an expression polymorphism, not only in osjar1 mutants but also in RNAi (RNA interference) lines of OsCOI1, another key member of the JA signaling pathway. This suggests that the expression of OsCHX14 is regulated by the JA signaling pathway. Green fluorescent protein (GFP)-tagged OsCHX14 protein was preferentially localized to the endoplasmic reticulum. Promoter-β-glucuronidase (GUS) analysis of transgenic rice revealed that OsCHX14 is mainly expressed in lodicules and the region close by throughout the flowering process. Characterization in yeast and Xenopus laevis oocytes verified that OsCHX14 is able to transport K+, Rb+and Cs+in vivo. Our data suggest that OsCHX14 may play an important role in K+homeostasis during flowering in rice.
authors.affiliation: Institute of Biology (IBL), Leiden University, Sylvius Laboratory, Sylviusweg 72, 2333 BE, PO Box 9505, 2300 RA Leiden, The Netherlands p.b.f.ouwerkerk.2@gmail.com yi.chen@jic.ac.uk.|Department of Metabolic Biology, John Innes Centre, Norwich NR4 7UH, UK.|Department of Sustainable Soils and Grassland Systems, Rothamsted Research, Harpenden AL5 2JQ, UK.
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, UK.
authors.forename: Jingkun
authors.initials: J
authors.lastname: Ma
authors.affiliation: Department of Metabolic Biology, John Innes Centre, Norwich NR4 7UH, UK.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Miller
authors.affiliation: State Key Laboratory of Crop Genetics and Germplasm Enhancement, MOA Key Laboratory of Plant Nutrition and Fertilization in Low-Middle Reaches of the Yangtze River, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 219500, China.
authors.forename: Bingbing
authors.initials: B
authors.lastname: Luo
authors.affiliation: Institute of Biology (IBL), Leiden University, Sylvius Laboratory, Sylviusweg 72, 2333 BE, PO Box 9505, 2300 RA Leiden, The Netherlands.|TNO Quality of Life, Zernikedreef 9, 2333 CK Leiden, PO Box 2215, 2301 CE Leiden, The Netherlands.
authors.forename: Mei
authors.initials: M
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No. 1 West Beichen Road, Chaoyang District, Beijing, 100101 China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Institute of Biology (IBL), Leiden University, Sylvius Laboratory, Sylviusweg 72, 2333 BE, PO Box 9505, 2300 RA Leiden, The Netherlands p.b.f.ouwerkerk.2@gmail.com yi.chen@jic.ac.uk.
authors.forename: Pieter B F
authors.initials: PB
authors.lastname: Ouwerkerk
mesh_terms: D000818:Animals; D017920:Antiporters / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D035264:Flowers / Q000187:drug effects / Q000378:metabolism*; D006706:Homeostasis / Q000187:drug effects; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism; D012275:Oryza / Q000187:drug effects / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism* / Q000494:pharmacology; D021381:Protein Transport / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism; D014982:Xenopus laevis
chemical_list: D017920:Antiporters; D010940:Plant Proteins; D011188:Potassium
keywords: CHX transporter; Flower; Jasmonate; Lodicule; Potassium; Rice