Advances in the Mechanistic Study of Environment-Sensitive Genic Male Sterility in Rice

Environment-sensitive genic male sterility (EGMS) lines are critical germplasm resources for two-line hybrid rice breeding. Their fertility is controlled by nuclear genes and precisely regulated through the perception of environmental factors such as temperature and photoperiod. EGMS combines genetic stability with environmental responsiveness, significantly enhancing the flexibility of hybrid breeding and playing an important role in the development and application of hybrid rice. Multiple types of EGMS have been identified in rice, including thermo-sensitive (TGMS), photoperiod-sensitive (PGMS), photoperiod- and thermo-sensitive (P/TGMS), humidity-sensitive (HGMS) and nitrogen-sensitive (NGMS). The sterility mechanisms involve environmental signal perception, gene expression regulation, and multilayered molecular interactions. The regulatory networks are complex and dynamically influenced by multiple environmental factors. Although significant progress has been made, key mechanisms still require further elucidation. This review systematically summarizes the molecular regulatory networks of EGMS, covering signal transduction, transcriptional regulation, post-transcriptional regulation, protein function, and metabolic regulation, with a focus on the environmental response mechanisms during critical developmental stages. In-depth understanding of gene-environment interactions will facilitate the development of novel sterile lines and precise control of critical sensitive periods, providing a solid theoretical foundation for stable and efficient hybrid breeding.