Advances in Rice Coleoptile Elongation: Implications for Direct-Seeded Rice Adaptation

Abstract

The rice coleoptile, a key protective structure during seed development, is crucial for safeguarding the plumule and facilitating seed germination. It plays a pivotal role in seedling emergence from soil, with its elongation characteristics being particularly important in direct-seeding systems. Coleoptile elongation is a complex biological process coordinately regulated by environmental factors, genetic background, plant hormones, and other signaling molecules, all of which interact to modulate elongation dynamics. This review systematically summarizes the mechanisms underlying coleoptile elongation, explores the regulatory roles of environmental and physiological factors, and synthesizes recent research progress on the identification of coleoptile-related QTLs, gene mining, and molecular regulatory mechanisms. Furthermore, we discuss the potential applications of coleoptile research in rice genetic improvement, aiming to provide a theoretical basis and novel insights for leveraging coleoptile traits in future breeding strategies.