753 / 2019-05-20 16:05:56

AtRZF1-Associated Protein 1 (AtRAP1), a negative regulator of dehydration response, assembles ubiquitin chain into E3 ubiquitin (Ub) ligase AtRZF1

E3 ubiquitin ligase,AtRZF1,dehydration stress response,proline

全体主题 > Abiotic Stress

The E3 Ub ligase AtRZF1 acts as an increasing the drought-induced sensitive property in Arabidopsis. To further investigate the function of AtRZF1 on osmotic stress, we isolated the AtRAP1, which interacts with AtRZF1 using the Yeast two-hybrid system. The AtRAP1-GFP fusion protein was observed exclusively in the nuclei of the root cells in the transgenic seedlings. Additionally, AtRAP1 has transcriptional activation activity and contains a DNA binding domain, indicating its function is as a transcriptional activator. The atrap1 RNAi mutants were less sensitive to osmotic stress than wild-type, whereas the AtRAP1-overexpressing transgenic lines were more hypersensitive during early seedling development, indicating AtRAP1 negatively regulates dehydration-mediated signaling. The ubiquitinylation assay showed that AtRAP1 increases the amount of Ub-conjugated AtRZF1. Moreover, genetic studies showed that the AtRZF1 gene could rescue the osmotic-insensitive phenotype of atrap1, suggesting AtRZF1 is epistatic to AtRAP1 in dehydration stress signaling. Taken together, our findings provide a new insight into the AtRZF1-AtRAP1 pathway mechanism in which controls proline content and dehydration response.