Arabidopsis TUA2 Gene Mediates Seed Germination Under ABA Stress

Objective)This study would characterize the TUA2 gene involving in seed germination under ABA stress in Arabidopsis by the method of reverse genetics. (Method) The Arabidopsis T-DNA inserted into TUA2 gene mutants were obtained from ABRC. The T-DNA insertion sites of mutants were analyzed by Tail PCR. Over-expression constructs of TUA2 were introduced into Arabidopsis by an Agrobacterium-mediated method. RT-PCR was used to detect TUA2 and ABA-responsive genes accumulation in mutants and transgenic plants. The seed germination of transgenic and mutant lines was tested on MS medium with different concentrations of ABA. (Result) The T-DNA was inserted into the gene promoter region in mutants tua2-1 and tua2-2, and led to the increasing accumulation of the TUA2. In the medium of MS/0.8 μmol·L -1 ABA, the seed germination rate of wild type was 76% after five days, whereas all the TUA2 over-expression lines, mutants and transgenic plants, were 6%-18%. The expression of ABII, HAB and P5CS was induced by ABA in wild type, but not in mutants and transgenics. (Conclusion) The T-DNA insertion of the mutants tua2-1 and tua2-2 resulted in the increasing expression of TUA2 gene. The TUA2 gene might be involved in plant responses to ABA by mediating the transcription of ABA-responsive genes.