Response Of Rice To Cd Stress And Cloning And Genetic Transformation Of OsPCR Gene

Cd is one of the most serious heavy metal pollution in the farmland and rice grain in China.Rice is one of the main food crops in China,so how to reduce the accumulation of Cd in rice grain to ensure the safety of rice grain had become a hot spot in recent years.This paper selected a low grain-Cd-accumulating rice variety Xiushui 11(Oryza sativa L.subsp.japonica cv.Xiushui11)and a high grain-Cd-accumulating rice variety Xiushui110(Oryza sativa L.subsp.Japonica cv.Xiushui110)as materials,studied the responses of the two rice cultivars growing in 0.8 mg/kg Cd contaminated soil and the cloning and genetic transformation of OsPCR gene in rice.The main results are as follows:1.After the Cd treatment,the Cd contents of Xiushui110 were higher than Xiushui 11 in different parts at the growth period,the inhibitory effect on the plant height,dry weight,panicle length,seed setting rate and grain weight of Xiushui110 was more obvious than that of Xiushui 11.2.After the Cd treatment,the expression of the Cd accumulation and transport-related genes(OsPCR1,OsPCR3,OsHMA2,OsHMA3)were significantly different in the two rice varieties at different growth stages.Compared with the control group,the expression of OsPCR1 and OsPCR3 genes changed significantly in Xiushui 11 and Xiushui 110,while the expression of OsHMA2 and OsHMA3 gene had no significant differences in Xiushui 11 and Xiushui 110.The expression of OsPCR1 and OsPCR3 genes in Xiushui 110 were higher than in Xiushui 11,this was consistent with the accumulation of Cd in different parts of the two rice varieties,so we indicated that OsPCR1 and OsPCR3 genes may be involved in regulating the accumulation of Cd in rice.3.We cloned the full-length CDS sequence of OsPCR1 and OsPCR3 and its interfering fragments,using Agrobacterium mediated genetic transformation,we screened T1 generation positive transgenic rice seedlings respectively.In the Cd treatment experiment on T1 generation transgenic rice seedlings and the wild type rice seedlings,the OsPCR1 and OsPCR3 interference expression transgenic lines were more sensitive to Cd stress,OsPCR1 and OsPCR3 overexpression transgenic lines enhanced tolerance to Cd stress,so we predicted that OsPCR1 and OsPCR3 played an important role in the tolerance of rice in response to Cd stress.