TgRAV1–TgWRKY74–TgACS13 module fine‐tunes ethylene biosynthesis to modulate waterlogging‐induced root vitality in the gymnosperm <i>Torreya grandis</i>

Waterlogging stress is a major abiotic stress that severely limits plant growth and development. However, little is known about the effects of waterlogging stress on the growth and development of gymnosperms. In this study, we demonstrated that the TgRAV1-TgWRKY74-TgACS13 module regulates ethylene-enhanced root vitality during waterlogging stress in the gymnosperm Torreya grandis. Root vitality, the physiological status of root tissues, reflects their metabolic activity and cell viability of roots. Waterlogging stress induces ethylene accumulation in T. grandis roots, thereby enhancing root vitality. The ethylene biosynthesis gene TgACS13 positively regulates root vitality under waterlogging stress by increasing ethylene levels. The transcription factors TgWRKY74 and TgRAV1 directly regulate TgACS13 expression by binding to its promoter. Furthermore, waterlogging stress activates TgWRKY74 to promote TgACS13 transcription and alleviates the inhibitory effect of TgRAV1 on its expression, resulting in ethylene-enhanced root vitality during waterlogging stress. In addition, TgRAV1 interacts with TgWRKY74 both in vivo and in vitro, reducing the transcriptional activity of TgWRKY74 by inhibiting its DNA-binding ability without affecting the transcriptional activity of TgRAV1. Therefore, the TgRAV1-TgWRKY74 module finely tunes TgACS13 expression to regulate ethylene accumulation through multiple mechanisms, thereby maintaining the vitality of T. grandis roots exposed to waterlogging stress.