title: A rice tonoplastic calcium exchanger, OsCCX2 mediates Ca2+/cation transport in yeast.
abstract: In plant cell, cations gradient in cellular compartments is maintained by synergistic action of various exchangers, pumps and channels. The Arabidopsis exchanger family members (AtCCX3 and AtCCX5) were previously studied and belong to CaCA (calcium cation exchangers) superfamily while none of the rice CCXs has been functionally characterized for their cation transport activities till date. Rice genome encode four CCXs and only OsCCX2 transcript showed differential expression under abiotic stresses and Ca(2+) starvation conditions. The OsCCX2 localized to tonoplast and suppresses the Ca(2+) sensitivity of K667 (low affinity Ca(2+) uptake deficient) yeast mutant under excess CaCl2 conditions. In contrast to AtCCXs, OsCCX2 expressing K667 yeast cells show tolerance towards excess Na(+), Li(+), Fe(2+), Zn(2+) and Co(2+) and suggest its ability to transport both mono as well as divalent cations in yeast. Additionally, in contrast to previously characterized AtCCXs, OsCCX2 is unable to complement yeast trk1trk2 double mutant suggesting inability to transport K(+) in yeast system. These finding suggest that OsCCX2 having distinct metal transport properties than previously characterized plant CCXs. OsCCX2 can be used as potential candidate for enhancing the abiotic stress tolerance in plants as well as for phytoremediation of heavy metal polluted soil.
authors.affiliation: Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi-110021, India.
authors.forename: Akhilesh K
authors.initials: AK
authors.lastname: Yadav
authors.affiliation: Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi-110021, India.
authors.forename: Alka
authors.initials: A
authors.lastname: Shankar
authors.affiliation: Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi-110021, India.
authors.forename: Saroj K
authors.initials: SK
authors.lastname: Jha
authors.affiliation: Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi-110021, India.
authors.forename: Poonam
authors.initials: P
authors.lastname: Kanwar
authors.affiliation: Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi-110021, India.
authors.forename: Amita
authors.initials: A
authors.lastname: Pandey
authors.affiliation: Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi-110021, India.
authors.forename: Girdhar K
authors.initials: GK
authors.lastname: Pandey
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects; D029681:Arabidopsis Proteins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002412:Cations / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism*; D017136:Ion Transport / Q000187:drug effects; D008094:Lithium / Q000494:pharmacology; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D019441:Plant Epidermis / Q000166:cytology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000378:metabolism*; D012964:Sodium / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D013347:Subcellular Fractions / Q000378:metabolism; D014026:Nicotiana / Q000166:cytology; D014617:Vacuoles / Q000187:drug effects / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D002412:Cations; D010940:Plant Proteins; D012333:RNA, Messenger; D049452:Green Fluorescent Proteins; D008094:Lithium; D012964:Sodium; D011188:Potassium; D002118:Calcium