Abstract
Bean bug,Riptortus clavatus, causes a serious damage of soybean production. The insect pest utilizes cysteine proteinases for protein digestion. In contrast, plants contain proteinous inhibitors, cystatins, against endogenous and exogenous cysteine proteinases including insect digestive proteases. In this research, we produced transgenic soybeans overexpressing plant cystatins to confer the insect resistance. We used three plant cystatins, OC1, mCC1 and JTC, from rice, corn, and Job's tears, respectively. Each of the cystatin genes was connected with a seed specific promoter derived from soybean 7S globulin gene or CaMV35S promoter, and nos-terminator, and the resultant cassette was inserted between the green fluorescence protein gene and the hygromycin resistance gene in a pUHG plasmid vector. The plasmids were introduced into soybean embryogenic cells by particle bombardment. Several transgenic plants were obteined by introduction of these constructs and we are now developing fixed lines for transgenes to analyze the resistance to R. clavatus.
