2025/06/20 by Yuwan Zhao, Zijing Huang, Ting Wang +4 · 2 voices
Biochemistry, Genetics and Molecular Biology · Agricultural and Biological Sciences · #Plant Reproductive Biology #Photosynthetic Processes and Mechanisms #Plant Molecular Biology Research
paper · doi:10.1111/jipb.13945
openalex publication_date 2025/06/20 · openalex created_date 2025/06/21 · openalex updated_date 2026/07/28
ABSTRACT Phosphatidylinositol 4,5‐bisphosphate (PI(4,5)P 2 ) is known to be an instrumental anionic phospholipid in governing pollen germination and pollen tube growth. However, the precise functions and regulatory mechanisms of PI(4,5)P 2 in pollen polarity establishment and germination remain poorly understood. Our previous studies demonstrated the pivotal involvement of Arabidopsis formin homology 5 (AtFH5)‐dependent vesicle trafficking in polarity establishment of pollen. Here, we observed that PI(4,5)P 2 accumulated and oscillated at the prospective germination site, a process closely associated with the rotational movement of AtFH5‐labeled vesicles. Disruption of the mobility of AtFH5‐labeled vesicles, either through AtFH5 mutation or pharmacological treatment, significantly perturbed the accumulation of PI(4,5)P 2 at the plasma membrane. Subcellular localization and genetic analysis revealed that two phosphatidylinositol 4‐phosphate 5‐kinases, AtPIP5K1 and AtPIP5K4, are essential for PI(4,5)P 2 oscillation at the germination site prior to pollen germination. Furthermore, we found that the dynamics of AtPIP5K4 depended on the mobility of AtFH5‐labeled vesicles and reduced PI(4,5)P 2 in turn disturbed the attachment of AtFH5‐labeled secretory vesicles to the plasma membrane. In conclusion, these findings collectively highlight the reciprocal regulation of AtFH5‐labeled secretory vesicles and PI(4,5)P 2 oscillations at the plasma membrane, providing critical insights into the molecular mechanism underlying polarity establishment during pollen germination.