Cloning And Functional Analysis On Gmpkib And Gmgme Gene From Soybean

Enviromental stresses, such as drought, high salinity and low temperature, have adverse effects on plant growth and development. To adapt with such detrimental condition, plants have developed a variety of defense strategies. So, revealing complex signal transduction pathways and gene networks of abioticst stress-responsive gene expression is important for dissecting the mechanisms of plants adaptation to stress, and crop breeding. In this study, we characterized expression patterns of GmPKlb and GmGME gene from soybean, and further studied their functions. And it was of great use for providing stress tolerance of soybean. The main results were listed as follows:1. Gene isolation and sequence blast analysis. In this study, GmPKlb genes were isolated from soybean. The full length was1,548bp. It contained a1,236bp open reading frame, encoding a polypeptide of412amino acids. The phylogenetic relationship also appeared that GmPKlb protein was more similar to TPKlb protein than other. And amino acid sequence alignment revealed that the homology was71.2%between GmPKlb and TPKlb.2. Analysis of GmPKlb gene expression characteristic. The specific expression pattern of GmPKlb gene at drought, high salinity, low temperature and ABA stress, indicated that the expression of GmPKlb gene was intensively induced by low temperature and ABA. Tissue-specific expression analysis of GmPKlb gene showed that GmPKlb gene was all tested in various tissues, but the levels of transcript were different. The highest and lowest levels of GmPKlb were observed in leaf and immature green beans (the bean of15DAF). Besides, the expression of GmPKlb was gradually increased during the seed filling process.3. Functional analysis of GmPKlb transgenic Arabidopsis for stress tolerance. Germination rates of GmPKlb transgenic Arabidopsis were obviously higher than that of wild-type Arabidopsis at low temperature stress. After treated by low temperature stress, survival rates of GmPKlb transgenic Arabidopsis31-4and50-2were18.91%and23.3%, respectively, while wild-type Arabidopsis was only11.8%. It was proved that over- expression of GmPKlb increased low temperature stress tolerance of Arabidopsis.4. Analysis of GmGME gene expression patterns. The specific expression pattern of GmPKlb gene at drought, high salinity, low temperature and ABA stress, showed that high salinity, low temperature and ABA significantly increased the transcript levels of GmGME.5. Functional analysis of GmGME transgenic Arabidopsis for stress tolerance. Germination rates of GmGME transgenic Arabidopsis was obviously higher than that of wild-type Arabidopsis at high salinity and low temperature stress. After treated by low temperature, survival rates had obviously difference between GmGME transgenic Arabidopsis and wild-type Arabidopsis. However, survival rates showed no significant difference at200mM NaCl stress. These results showed that over-expression of GmGME inereased salt stress and low temperature tolerance of Arabidopsis.