The Calcineurin B-Like Ca2＋ Sensors CBL1 and CBL9 Function in Pollen Germination and Pollen Tube Growth in Arabidopsis  

作　　者：Anette Maihs Leonie Steinhorst Jian-Pu Han Li-Ke Shen Yi Wang Jorg Kudla 

机构地区：[1]Institut for Biologie und Biotechnologie der Pflanzen, Universitat MOnster, Schlossplatz 4, 48149 MOnster, Germany [2]State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, National Plant Gene Research Center (Beijing), China Agricultural University, Beijing 100193, China

出　　处：《Molecular Plant》2013年第4期1149-1162,共14页分子植物（英文版）

摘　　要：Ca2＋ has been established as an important second messenger regulating pollen germination and tube growth. However, to date, only a few signaling components have been identified to decode and relay Ca2＋ signals in growing pollen tubes. Here, we report a function for the calcineurin B-like （CBL） Ca2＋ sensor proteins CBL1 and CBL9 from Arabidopsis in pollen germination and tube growth. Both proteins are expressed in mature pollen and pollen tubes and impair pollen tube growth and morphology if transiently overexpressed in tobacco pollen. The induction of these phenotypes requires efficient plasma membrane targeting of CBL1 and is independent of Ca2＋ binding to the fourth EF-hand of CBL1. Overexpression of CBL1 or its closest homolog CBL9 in Arabidopsis renders pollen germination and tube growth hypersensitive towards high external K＋ concentrations while disruption of CBL1 and CBL9 reduces pollen tube growth under low K~ conditions. Together, our data identify a crucial function for CBL1 and CBL9 in pollen germination and tube growth and suggest a model in which both proteins act at the plasma membrane through regulation of K＋ homeostasis.Ca2＋ has been established as an important second messenger regulating pollen germination and tube growth. However, to date, only a few signaling components have been identified to decode and relay Ca2＋ signals in growing pollen tubes. Here, we report a function for the calcineurin B-like （CBL） Ca2＋ sensor proteins CBL1 and CBL9 from Arabidopsis in pollen germination and tube growth. Both proteins are expressed in mature pollen and pollen tubes and impair pollen tube growth and morphology if transiently overexpressed in tobacco pollen. The induction of these phenotypes requires efficient plasma membrane targeting of CBL1 and is independent of Ca2＋ binding to the fourth EF-hand of CBL1. Overexpression of CBL1 or its closest homolog CBL9 in Arabidopsis renders pollen germination and tube growth hypersensitive towards high external K＋ concentrations while disruption of CBL1 and CBL9 reduces pollen tube growth under low K~ conditions. Together, our data identify a crucial function for CBL1 and CBL9 in pollen germination and tube growth and suggest a model in which both proteins act at the plasma membrane through regulation of K＋ homeostasis.

关 键 词：CALCIUM CBL pollen tube growth POTASSIUM 

分 类 号：Q55[生物学—生物化学] S661.2[农业科学—果树学]