Functional Analysis Of Calcineurin B-Like Proteins Gene OsCBL7 From Rice

Rice is one of the most important staple crops cultivated worldwide.In the many rice-growing areas there are frequent drought,salinity,extreme temperature abiotic factors to impede rice growth,development and production.It has been one of main objects for the researchers to elucidate functions of resistance or tolerance-related genes in plabnts to a variety of stresses and breed new varieties with tolerance to stresses.This thesis aims to explore the function of OsCBL7 gene involved in rice tolerance to stresses by transgenic methods.Some novel results are given as follows:Based on the similarity of sequence,OsCBL7 gene was identified by searching the rice japonica genome database,which was located on chromosomes 2.To investigate the cellular location of rice OsCBL7 protein,a 35S::OsCBL7-GFP gene fusion construct was transformed into the onion epidermal cells by particle bombardment approach.The results showed that the GFP fluorescence exclusively in the plasma membrane,suggesting that OsCBL7 is a membrane-targeting protein.Two plant expression vectors carrying sense or antisense rice OsCBL7 gene respectively under the regulation of cauliflower mosaic virus 35s promoter were constructed.The mature embryo derived calli were infected by Agrobacterium tumefaciens EHA105 with pCAM-OsCBL7 or pCAM-AsOsCBL7,from which hygromycin resistant plants were obtained.PCR identification proved that the OsCBL7 or AsOsCBL7 was integrated into the genomes of the rice plants.RT-PCR analysis confirmed that OsCBL7 in the transgenic plants carrying sense OsCBL7 gene was overexpressed and that carrying antisense gene was depressed.The stress assays showed that overexpression of OsCBL7 in rice significantly enhanced the tolerance of transgenic plants to drought stress.Inhibition OsCBL7 expression increased the sensitivity of transgenic plants to cold stress.