Arabidopsis thaliana CML25 mediates the Ca2+ regulation of K+ transmembrane trafficking during pollen germination and tube elongation. (18th June 2015)

• Record Type: Journal Article
• Authors: Wang, Shuang‐Shuang; Diao, Wen‐Zhu; Yang, Xue; Qiao, Zhu; Wang, Mei; Acharya, Biswa R.; Zhang, Wei
• Is Part Of: Plant, cell and environment. Volume 38:Number 11(2015:Nov.)
• Page Start: 2372
• Page End: 2386
• Publication Date: 2015-06-18
• Subjects: calmodulin‐like protein -- K+ channel -- patch clamp -- pollen tube growth; Plant physiology -- Periodicals; Plant cells and tissues -- Periodicals; Plant communities -- Periodicals; 581.105
• DOI: 10.1111/pce.12559
• Languages: English
• ISSNs: 0140-7791

Abstract

Abstract: The concentration alteration of cytosolic‐free calcium ([Ca 2+ ]cyt ) is a well‐known secondary messenger in plants and plays important roles during pollen grain germination and tube elongation. Here we demonstrate that CML25, a member of calmodulin‐like proteins, has Ca 2+ ‐binding activity and plays a role in pollen grain germination, tube elongation and seed setting. CML 25 transcript was abundant in mature pollen grains and pollen tubes, and its product CML25 protein was primarily directed to the cytoplasm. Two independent CML 25 loss‐of‐function T‐DNA insertion mutants suffered a major reduction in both the rate of pollen germination and the elongation of the pollen tube. Also, pollen grains of cml25 mutants were less sensitive to the external K + and Ca 2+ concentration than wild‐type pollen. The disruption of CML 25 increased the [Ca 2+ ]cyt in both the pollen grain and the pollen tube, which in turn impaired the Ca 2+ ‐dependent inhibition of whole‐cell inward K + currents in protoplasts prepared from these materials (pollen grain and pollen tube). Complementation of cml25‐1 mutant resulted in the recovery of wild‐type phenotype. Our findings indicate that CML25 is an important transducer in the Ca 2+ ‐mediated regulation of K + influx during pollen germination and tube elongation. Abstract : Ca 2+ is a ubiquitous secondary messenger and plays an essential role in regulation of pollen grain germination and pollen tube elongation, but the fundamental regulatory network downstream still remains largely unknown. In this study, the Arabidopsis CML25 (Calmodulin‐Like protein 25), a member of predicated Ca 2+ sensor family, was found to be involved in cytosolic Ca 2+ regulation of K + influx of pollen grains and pollen tubes, and subsequently to regulate pollen grain germination, pollen tube growth and seed setting rate positively. The physiological roles and the molecular mechanisms of CML25 in pollen grains and pollen tubes uncovers a new signal pathway downstream of Ca 2+ signal.