Heat-stable protein PGSL1 enhances pollen germination and tube growth at high temperature
Dong Qian, T. M. Li, Chen Zheng, Mu-xuan Wang, Shuyuan Chen, Chengying Li, Jun An, Yang Yang, Yue Niu, Lizhe An, Yun Xiang
Abstract
Global warming intensifies extreme heat events, threatening crop reproduction by impairing pollen development, germination, and tube growth. However, the mechanisms underlying pollen heat responses remain elusive. The actin cytoskeleton and actin-binding proteins (ABPs) are crucial in these processes, yet their roles under heat stress are poorly understood. Here, we identify a mutant, pollen germination sensitive to LatB (pgsl1), via forward genetic screening. PGSL1 encodes a heat-stable, plant-specific ABP that binds and stabilizes actin filaments (F-actin), preventing heat-induced denaturation. High temperatures reduce F-actin content but promote bundling in pollen tubes. Notably, pgsl1 mutants exhibit decreased F-actin abundance and bundling under heat stress compared to wild-type plants. These findings highlight PGSL1 as a key regulator of actin dynamics, essential for pollen heat tolerance, offering potential strategies to enhance crop resilience in a warming climate. The actin cytoskeleton plays crucial roles in pollen development, germination, and tube growth. Here the authors show that PGSL1, an Arabidopsis heat-stable actin binding protein stabilizes actin filaments under high temperatures, preventing denaturation and maintaining F-actin dynamics.