Genetic and epigenetic mechanisms underlying male reproductive thermotolerance

Male germline development in plants is highly sensitive to heat stress, with elevated temperatures frequently impairing male fertility and consequently reducing seed production. Indeed, recent global warming has decreased major crop yields, emphasizing the urgent need to elucidate the molecular and cellular mechanisms underlying heat-induced male sterility. This review synthesizes current knowledge on how heat stress disrupts microsporogenesis and microgametogenesis, and how plants counteract these stresses through diverse thermotolerance mechanisms. We emphasize temperature-sensitive processes, including meiotic progression in male germ cells, programmed cell death of somatic tapetal nurse cells, and post-meiotic pollen tube development. We further discuss how epigenetic regulators enhance thermotolerance by reprogramming DNA methylation landscapes and modulating histone variant distribution. Finally, we propose future directions aimed at understanding the mechanisms of reproductive thermotolerance from the epigenetic perspective.