Root growth control by negative regulation of MYB50 under ABA signaling in <i>Arabidopsis</i>

Plant growth is finely tuned by environmental changes, with abscisic acid (ABA) playing a key role in balancing stress tolerance and growth regulation. The target genes of MYB50, which regulate root growth, include genes that respond to ABA; however, the precise role of MYB50 in ABA signaling remains unclear. Therefore, this study aimed to elucidate the function of MYB50 under ABA signaling. Our experiments demonstrated that ABA treatment reduced MYB50 expression and promoted the degradation of MYB50 protein. This degradation alleviates the inhibitory effects of MYB50 on root growth. Furthermore, ABA differentially regulates MYB50 compared with ABI5, another key transcription factor involved in root growth under ABA signaling, suggesting that ABA uses distinct regulatory pathways for root growth. Our study suggests that ABA controls root growth by modulating MYB50 at both the transcriptional and post-translational levels, thus ensuring balanced root development in response to ABA.