Apoplastic calmodulin promotes self-incompatibility pollen tube growth by enhancing calcium influx and reactive oxygen species concentration in Pyrus pyrifolia
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This study indicated that Ca 2+ , ROS and actin filaments were involved with CaM in regulating pollen tube growth and providing a potential way for overcoming pear self-incompatibility.
Calmodulin (CaM) has been associated with various physiological and developmental processes in plants, including pollen tube growth. In this study, we showed that CaM regulated the pear pollen tube growth in a concentration-dependent bi-phasic response. Using a whole-cell patch-clamp configuration, we showed that apoplastic CaM induced a hyperpolarization-activated calcium ion (Ca2+) current, and anti-CaM largely inhibited this type of Ca2+ current. Moreover, upon anti-CaM treatment, the reactive oxygen species (ROS) concentration decreased and actin filaments depolymerized in the pollen tube. Interestingly, CaM could partially rescue the inhibition of self-incompatible pear pollen tube growth. This phenotype could be mediated by CaM-enhanced pollen plasma membrane Ca2+ current, tip-localized ROS concentration and stabilized actin filaments. These data indicated that Ca2+, ROS and actin filaments were involved with CaM in regulating pollen tube growth and provide a potential way for overcoming pear self-incompatibility.
KeywordsPollen tube Pear Calmodulin Self-incompatibility
This work was supported by the National Natural Science of China (31,071,759, 31,230,063 and 31,272,119), Doctoral Fund of Ministry of Education of China (20120097120046), Fund for Independent Innovation of Agricultural Sciences in Jiangsu Province (CX(11)1013, CX(13)3,010), National Natural Science Foundation of Jiangsu Province (BK2011067, BK2012366), and the Fundamental Research Funds for the Central Universities (KYRC201201).
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