Construct rice expression vector of CTB-ureB fusion gene pCWUN:(1) Fusion and clone of CTB gene and ureB gene: CTB gene and Hp ureB gene were amplified by high-fidelity PCR respectively from plasmid pGEM-CTB and Hp genome, and then they were fused by PCR.

• 构建CTB-ureB融合基因的水稻表达载体pCWUN：