The Function Validation Of The Candidate Genes Sdg And MT2 In Rice(Oryza Sativa L.) By RNAi

The increase in population and decrease of the agricultural acreage in China has brought about crisis in food supply.This obliges us to improve yield per unit land area. The dwarf and tillering traits are vital for yield improvement of crops such as rice and wheat due to their influences on water tolerance, fertilizer and number of spikes. Therefore, more and more attention has been paid to the detection and use of novel dwarf and more tillering gene resources.Recently, RNAi has been developed as a new method of gene silence to study the regulation of gene expression and gene function. It is siRNA (small interfering RNA) that caused the homologous genes in the cells to be silent. The essence of RNAi is that siRNA combined with target mRNA specifically, which causes the target mRNA to degrade, so the translation of the target mRNA is terminated. Gene silence is a vital mechanism of gene expression regulation and has significant bio-functions. In our study, RNAi was employed to study the candidate semidwarf gene Sdg and the candidate strong tillering gene MT2 in rice.A cDNA library of the rice at five leaf was constructed and used to amplify the fragments of the two genes, and to construct the high expression vectors pCam23A of these genes. The constructed vectors were transformed to the calli generated from mature embryos and immature embryos of the Japonica Nipponbare by the Agrobacterium-mediated method, and the transgenic plants regenerated from the G418 resistant calli were obtained. The detection of these transgenic plants via PCR and phenotype identification was used to verify that small RNA fragments had been combinated into the genome and dwarf transgenic plants were abtained, but strong tillering transgenic plants were not abtained. Segregation of high and semidwarf plants of the T1 family was fit to the ratio 3:1, which suggested that this gene is the right Sdg gene to control the semidwarf trait.