523 / 2019-03-04 15:49:30

RSM1, an Arabidopsis MYB protein, interacts with HY5/HYH to modulate seed germination and seedling development

RADIALIS-LIKE SANT/MYB 1 (RSM1), ABI5, abscisic acid, abiotic stress, HY5, HYH, seed germination, seedling development.

全体主题 > Abiotic Stress

RADIALIS-LIKE SANT/MYB 1 (RSM1) belongs to a MYB-related subfamily, and previous transcriptome analysis suggests that RSM1 may play roles in plant development, stress responses and plant hormone signaling. We show that down-regulation or up-regulation of RSM1 expression alters the sensitivity of seed germination and cotyledon greening to abscisic acid (ABA), NaCl and mannitol in Arabidopsis. The expression of RSM1 is dynamically regulated by ABA and NaCl. Transcription factors ELONGATED HYPOCOTYL 5 (HY5) and HY5 HOMOLOG (HYH) regulate RSM1 expression via binding to the RSM1 promoter. Genetic analyses reveal that RSM1 mediates multiple functions of HY5 in responses of seed germination, post-germination development to ABA and abiotic stresses, and seedling tolerance to salinity. Pull-down and BiFC assays show that RSM1 interacts with HY5/HYH. RSM1 and HY5/HYH may function as a regulatory module in responses to ABA and abiotic stresses. RSM1 binds to the promoter of ABA INSENSITIVE 5 (ABI5), thereby regulating its expression, while RSM1 interaction also stimulates HY5 binding to the ABI5 promoter. However, no evidence was found in the dual-luciferase transient expression assay to support that RSM1 enhances the activation of ABI5 expression by HY5. In summary, HY5/HYH and RSM1 may converge on the ABI5 promoter and regulate ABI5 expression and ABI5-downstream ABA and abiotic stress-responsive genes, thereby improving the adaption of plants to the environment.