title: Apoplastic calmodulin promotes self-incompatibility pollen tube growth by enhancing calcium influx and reactive oxygen species concentration in Pyrus pyrifolia.
abstract: 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.
authors.affiliation: College of Horticulture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, No 6. Tongwei Road, Nanjing, 210095, China.
authors.forename: Xueting
authors.initials: X
authors.lastname: Jiang
authors.forename: Yongbin
authors.initials: Y
authors.lastname: Gao
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Zhou
authors.forename: Jianqing
authors.initials: J
authors.lastname: Chen
authors.forename: Juyou
authors.initials: J
authors.lastname: Wu
authors.forename: Shaoling
authors.initials: S
authors.lastname: Zhang
mesh_terms: D000199:Actins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D002147:Calmodulin / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D053205:Pollen Tube / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D054817:Pollination; D031989:Pyrus / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D060436:Self-Incompatibility in Flowering Plants
chemical_list: D000199:Actins; D002147:Calmodulin; D017382:Reactive Oxygen Species; D002118:Calcium