Abstract: The phytohormone abscisic acid is a key endogenous messenger in plants’ response to abiotic stress by regulating some crucial gene expression. Founded in previous research in this lab, a RING structure of E3 ligase At5g66070, through bioinformatics analysis found could be induced by ABA.So we analyse its related physiological function under the condition of ABA treatment .Gene At5g66070 was studied before in this laboratory. The results showed that the gene expression was significantly increased after 10μM ABA treatment. The cellular localization of At5g66070 was predominantly found in the nuclear,indicating At5g66070 is a nuclear protein. No full-length At5g66070 transcript was detected in the mutant by DNA and RT-PCR analysis, suggesting that At5g66070 is a loss-of-function mutant.Germinated evenly-grown seedlings were then transferred to MS plates supplemented with or without ABA.At5g66070 mutant showed shorter primary roots compared with the overexpression lines under ABA treatment.It means the mutant is more sensitive than wide type and overpression lines. The 10μM ABA treatment induced stomata closure in mutant, but had no effect on wild type and overexpression lines. Using RT-PCR to analyze the related genes in Arabidopsis ABA singnaling pathway.Our results indicate that At5g66070 is a negative regulator of ABA signaling.
