Effects Of Mercury On The Growth Of Rice Seedlings And Relationship Of OsPP2C Gene To Mercury Tolerance

Mercury is one of the most toxic heavy metals and seriously affects the growth of rice. To investigate the mechanism of mercury tolerance in rice, we compared the growth of seedlings grown under mercury stress. In addition, we carried out the genetic transformation of OsPP2C, a gene predicted by QTL analysis of the rice seedlings under mercury stress. The results are summarized as follows:1. Seeds of Nipponbare and 9311 germinated in a sterile environment. Seedlings were treated with HgCl2 at the concentration of 0,5,10,15μM for ten days, respectively. The relative root length, relative shoot height and relative fresh weight of 9311 were higher than Nipponbare. Hg2+ content of shoot is same between 9311 and Nipponbare while Hg2+ content of Nipponbare in root is significant higher than 9311.2. Bioinformatics analysis on the protein OsPP2C showed that it has the typical serine/threonine catalytic domain. It is the typical protein phosphatase 2C and has high identity to the protein phosphatase 2C from other species.3. Prokaryotic expression strains of Escherichia coli with pET-24a or pET-24a-OsPP2C were treated with HgCl2, CdCl2, and CuSO4. The spot assay showed that the strain with pET-24a-OsPP2C grew better than that with pET-24a. The bacterial growth curve showed the same result.4. The overexpression vector and RNAi vector of OsPP2C were constructed and the transgenic lines of Nipponbare were obtained by agrobacterium-mediated method. The results of q-PCR showed that four overexpression lines had higher expression of OsPP2C than the wild type while four RNAi lines exhibited the lower expression than the wild type. These transgenic lines could be used for further study.