Integration of ovular signals and exocytosis of a Ca2+ channel by MLOs in pollen tube guidance

编号 040023302

推送时间 20200406

研究领域 森林培育 

年份 2020 

类型 期刊 

语种 英语

标题 Integration of ovular signals and exocytosis of a Ca2+ channel by MLOs in pollen tube guidance

来源期刊 Nature Plants

期 第233期

发表时间 20200213

关键词 Ca2+;  Stress response;  Spatiotemporal regulation; 

摘要       The spatiotemporal regulation of Ca2+ channels at the plasma membrane in response to extracellular signals is critical for development, stress response and reproduction, but is poorly understood. During flowering-plant reproduction, pollen tubes grow directionally to the ovule, which is guided by ovule-derived signals and dependent on Ca2+ dynamics. However, it is unknown how ovular signals are integrated with cytosolic Ca2+ dynamics in the pollen tube. Here, we show that MILDEW RESISTANCE LOCUS O 5 (MLO5), MLO9 and MLO15 are required for pollen tube responses to ovular signals in Arabidopsis thaliana. Phenotypically distinct from the ovule-bypass phenotype of previously identified mutants, mlo5?mlo9 double-mutant and mlo5?mlo9?mlo15 triple-mutant pollen tubes twist and pile up after sensing the ovular cues. Molecular studies reveal that MLO5 and MLO9 selectively recruit Ca2+ channel CNGC18-containing vesicles to the plasma membrane through the R-SNARE proteins VAMP721 and VAMP722 in trans mode. This study identifies members of the conserved seven transmembrane MLO family (expressed in the pollen tube) as tethering factors for Ca2+ channels, reveals a novel mechanism of molecular integration of extracellular ovular cues and selective exocytosis, and sheds light on the general regulation of MLO proteins in cell responses to environmental stimuli.

服务人员 孙小满

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