The Expression Patterns Of GHMP1 Gene And Functional Study Of T-DNA Mutant In Arabidopsis

GHMP super kinase family is important protein kinases in eukaryotes. The main role is to catalyze protein phosphorylation by transfering the phosphate of ATP to amino acid residues of the specific substrate, which was involved in a variety of signal transduction. So far, the seven genes have been identified in Arabidopsis belonging to GHMP super kinase family, but little was known of its physiological functions, so the study of functions of these genes is significant. In the present study, the expression patterns of GHMP1 gene and functional study of T-DNA mutant in Arabidopsis were analysed. The main results of this paper can be summarized as follows.Firstly, the GHMP1 gene expression patterns were studied. The real time PCR results showed that there were a high transcription level in roots and flowers, but low level in leaf, petiole, and stem, indicating GHMP1 belonged to tissue-specific gene. The expression of GHMP1 gene was induced by ABA and NaCl. When the young seedlings for 14 days old were treated with 10 uM ABA for an hour or with 100 mM NaCl for two hours, the transcription level of GHMP1 gene was up to its peak, suggesting that GHMP1 gene may mediate the related to ABA and salt stress-induced signaling pathways. The transcription levels of a series of stress response genes (abi1, abi2, KIN1/2, SOS2/3, OST1, RD29A/B, RAB18, RD22, DREB1/2A) related to ABA and salt responses were compared by real-time PCR between the ghmp1-1 mutant and wild type with 10 uM ABA treatment for an hour, the distinct differences in transcription levels in these genes were displayed as the deletion of GHMP1 gene. Therefore, we can presume the GHMP1 gene play an important role in ABA signal pathway. Secondly, two GHMP1 gene T-DNA homozygous mutant ghmp1-1 and ghmp1-2 were screened through the"double-primer"method and were identified by the RT-PCR method. Thirdly, the functions of T-DNA insertion mutants of the GHMP1 gene in Arabidopsis were studied by the reverse genetics research methods. The changes in phenotype such as seed germination rate, root length, stomatal aperture, rate of water loss between the mutant and wild-type were observed. The results showed that mutants are less sensitive to exogenous ABA and NaCl in seed germination and root elongation compared with wild-type. The further evidence showed that the role of GHMP1 gene response to salt and ABA signaling pathways in Arabidopsis, which proved that its activation role as a stress-related transcription factor. This work provided some invaluable references for the physiological functions of the other GHMP genes.