The AP2/ERF transcription factor CsRAV1 represses CsGL2 to regulate the trichome development of tea plants

Trichomes on tea leaves play crucial roles in defending against biotic and abiotic stresses and contributing to the quality traits of tea, yet their molecular regulatory mechanisms remain relatively limited. In this study, we identified an AP2/ERF transcription factor (CsRAV1) from transcriptome data of tea germplasms with contrasting trichome densities. Its expression pattern negatively correlated with trichome density across diverse tea cultivars and tissues. Overexpression of CsRAV1 in Arabidopsis significantly reduced leaf trichome density, which confirmed its critical role in the development of trichomes. Furthermore, virus-induced gene silencing (VIGS) of CsRAV1 in tea leaves significantly increased trichome density, providing direct functional evidence that CsRAV1 acts as a negative regulator of trichome development in tea plants. Moreover, CsRAV1 is bound directly to the CAACA motif of the trichome developmental regulatory gene (CsGL2) promoter and down-regulates its expression. Exogenous salicylic acid (SA) application significantly reduced both trichome density and length in tea plants, accompanied by upregulated expression of CsRAV1 and downregulated expression of CsGL2. Our results uncover that the CsRAV1-CsGL2 regulatory module responds to SA signals to regulate trichome development in tea plants. These findings provide novel insights into the regulatory mechanism underlying trichome development in tea plants.