Functional Analysis Of Transcription Factor RAP2.4f In Arabidopsis Thaliana

Arabidopsis RAP2.4f genes belong to AP2/ERF transcription factor family, members of the family play an important role in plant growth and development and in defense against biotic and abiotic stress. In order to know whether RAP2.4f is involved in plant drought stress pathway, Related experiments are designed, and the results as following:1. By using bio informatics methods on the structure of RAP2.4f protein, promoter cis element, nuclear localization is analyzed. Results show that RAP2.4f gene contains a conserved AP2/ERF domain, which belongs to the family of AP2/ERF transcription factor DREB subfamily, promoter region contains a multiple ABA, GA and abiotic stress response elements, and RAP2.4f gene is located in the nucleus.2. In order to further study the biological function of RAP2.4f gene, the RAP2.4f overexpress ion vector was constructed and transformed into Arabidopsis thaliana by Agrobacterium. The RAP2.4f overe xpress ion lines were obtained. T-DNA insertion mutants were identified, and the homozygous rap2.4fT-DNA insertion mutants were obtained;3. Subcellular localization experiments prove the RAP2.4f gene is located in the nucleus and quantitative real-time PCR found RAP2.4f gene expression level was higher in Arabidopsis rosette leaves and roots. Treatment 2 week old wild-type Arabidopsis thaliana with ABA,GA,salt, mannitol, cold and drought, quantitative real-time PCR analysis the expression level of RAP2.4f, Results show RAP2.4f gene expression was induced by ABA,salt, mannitol, cold and drought, however GA was slight induction.4. Drought treatment with the RAP2.4f over-express ion plant ?RAP2.4fox1? RAP2.4fox2?, wild type ?Col-0, Col-4?, the deletion mutant rap2.4f?salk₁49506c? for 20 to 25 days, It was found that the drought resistant ability of the over expressing plants was stronger than that of the wild type, while the drought resistant ability of the mutant rap2.4f was weaker than that of the wild type; Using 3%PEG to treatment each strain, it was found that the root growth of wild type plants was significantly inhibited, and the inhibition degree of the over expression of plant roots was decreased.5. The RAP2.4f over-expression lines and T-DNA insertion mutant rap2.4f showed a difference in water loss, stomatal opening, proline accumulation. The RAP2.4f over-express ion lines showed a slower rate of water loss then wild type Col-4 leaves, and the rap2.4f mutants showed a faster rate of water loss then wild type Col-0 leaves. After treated with different concentrations of ABA, RAP2.4f over-expression lines relative to Col-4 stomatal closure to a greater degree, and mutant rap2.4f relative to wild-type Col-0 stomatal closure of smaller; in the overexpression lines in proline accumulation rate than the wild type faster, and in the mutant rap2.4f proline accumulation rate than the wild type slow.6. Quantitative PCR analysis showed that the expression of RD29B?ABF3? RD22?RAB18 and in the RAP2.4f over-expression lines and mutant rap2.4f was significantly changed after drought treatment.All results suggested that RAP2.4f is involved in drought stress response, which plays an important role in improving the ability of plants to drought.