Rice Cinnamoyl CoA Reductase-like Gene OsCCR14 Involved in Heat Stress via Regulation Lignin and Flavonoid Accumulation

Cinnamoyl-CoA reductases (CCRs) and their homologs, CCR-like proteins, play key roles in plant secondary metabolism and defense against environmental stresses; however, their functions in heat stress responses remain unclear. In this study, phylogenetic and sequence alignment analyses revealed that OsCCR14 encodes a CCR-like protein. qRT-PCR assays showed that OsCCR14 is predominantly expressed in roots and is induced by heat stress. Notably, overexpression of OsCCR14 increased lignin content, and transgenic plants with enhanced OsCCR14 expression exhibited higher flavonoid accumulation in roots. Conversely, knockout of OsCCR14 reduced flavonoid content and impaired seedling heat tolerance. Furthermore, OsCCR14 overexpression improved heat tolerance, accompanied by increased root lignification and flavonoid accumulation. These results indicate that OsCCR14 acts as a critical regulator of lignin and flavonoid metabolism, thereby providing a potential target for enhancing crop heat tolerance.