Anther and pollen thermotolerance: molecular mechanisms and implications for plant reproduction under heat stress

This work highlights pollen thermotolerance as vital for reproductive success under heat stress, integrating molecular regulation, gene mapping, and breeding strategies to accelerate development of resilient, high-yielding crop varieties. Heat stress has emerged as a major abiotic constraint that significantly reduces crop productivity under changing climatic conditions. The reproductive phase is among the most heat-sensitive stages of plant development. High temperatures disrupt multiple reproductive processes, including anther development, tapetal functioning, microsporogenesis, pollen maturation, and pollen-pistil interactions, thereby compromising fertilization success and crop yield. To counteract these detrimental effects, plants have evolved adaptive mechanisms that enable reproductive tissues to maintain functionality under high-temperature stress. Pollen thermotolerance, defined as the ability of pollen grains to withstand high temperatures and produce functional pollen grains for successful fertilization, is a key determinant of crop yield stability. This review provides a focused synthesis of the cellular and molecular mechanisms, such as heat shock protein expression, antioxidant defense systems, hormonal signaling, and epigenetic regulation, that collectively confer pollen thermotolerance. Furthermore, we examine how recent applications of omics technologies (transcriptomics, proteomics, and metabolomics) and genomic approaches that provide comprehensive understanding of the molecular and biochemical mechanisms underlying pollen thermotolerance. By integrating these mechanistic insights with quantitative and predictive modeling, researchers can more effectively identify and deploy heat-resilient reproductive traits. This integrated approach is essential for accelerating the development of heat-resilient crop varieties to ensure stable agricultural productivity in future.