Studies On Stress Resistance Mechanism Of Antarctic Bryum Pseudotrique MBF1Gene

In nature, low temperature, soil salination, drought and flood can affect plant growth and survival adversely, they also limit the geographical distribution and yield of crops worldwide. These environmental factors are called environmental stress.Transcription factors and regulatory genes are main factors mediated the acclimation of plants to environmental stress. Transcriptional coactivator is closely bound up with the activity of transcriptional factors, it can enhance the transcription activity through promoting the combination of transcriptional factors to cis-acting element.Multiprotein bridging factor1(MBF1) is a transcriptional coactivator, and it is highly conserved during evolution. MBF1is involved in diverse biological processes such as hormone-regulated lipid metabolism, central nervous system development, endothelial cell differentiation and histidine metabolism. MBF1proteins from different organisms bind with TBP through interacting with GCN4, c-Jun, ATF1or other nuclear receptors, finally activate gene transcription.MBF1gene was cloned from the antarctic Bryum pseudotrique using RACE-PCR, then a447bp fragment was cloned, it was named BpMBFl. Homology comparison between BpMBFl and other creatures with the published MBF1amino acid sequence was made, the results showed that BpMBFl shares high homology with other species at amino acid level.3D-pridiction for protein of BpMBFl and AtMBF1c showed that their C-terminal domain share high similarity, so AtMBF1c gene was also cloned.After cloning the gene, we constructed the plant binary over-expression vector pBI121-BpMBFl and pBI121-AtMBF1c, containing the cauliflower mosaic virus35S promoter and NOS terminator. The BpMBFl and AtMBF1c under regulation of CaMV35S promoter were transformed into Arabidopsis thaliana wild type by Agrobacterium-mediated transformation using the floral dip method. BpMBFl and AtMBF1c were also transformed into Atmbf1c homozygous mutant to complement phenotype. Environmental stress analysis on WT, Mutant, Over-expression and Mutant complemented with BpMBFl and AtMBF1c plants shows that BpMBFl plays an important role in environmental stress. And BpMBFl transfered from the cytosol to the nucleus response to cold stress.23genes interacting with BpMBFl were identified using yeast two-hybrid system, including Histone H3, Dehydrogenase and Acyl-CoA synthetase. Some of the proteins encoded by these genes are associated with protein and carbohydrate metabolism, indicating that BpMBFl may influence plant resistance to stress through regulating interactions between these genes.