Co-expression Of Antimicrobial Proteins In Tobacco Improves It's Disease Resistance

Plant diseases is one of the main constraints in agricultural cultivation. At present, one important common solution to this problem is to apply resistant resource to develop new disease-resistant varieties by common breeding method. But this time-consuming and labor-consuming way can't meet the great need of production because of the rapid variation of pathogen and the limited resistant resources. With the speedy development of molecular biology, an important means has been found to gain disease-resistant plants by transferring disease-resistant gene into the interesting plant through gene engineering technology.In this experiment, we transferred the dual-gene genecreated from a chitinase gene, Bbchitl, from Beauveria bassiana and a non-specific lipid transfer proteins gene, LIAMP2, from motherwort (Leonurus japonicus Houtt), into tobacco (Nicotiana tabacum var. Xanthi) through leaf-dish transformation mediated by Agrobacterium. Meanwhile, we also obtained the transgenic tobacco containing a ribosome-inactive protein gene LJAMP1 and a non-specific lipid transfer protein gene LJAMP2 from motherwort by cross-breeding using homozygous transgenic tobacco lanes with LJAMP1 and LJAMP2 gene, respectively. The resulting plants were screened for resistance to Ralstonia solanacearum. Disease resistance was correlated with the level of expression of either antimicrobial protein when expressed alone. Plants expressing both antimicrobial proteins simultaneously were more resistant than plants expressing either antimicrobial protein at the same level; analyses indicated that the two antimicrobial proteins (Bbchitl and LJAMP2, or LJAMP1 and LJAMP2) acted synergistically to reduce disease. We believe that this is the first report of in planta synergy between a chitinase gene and a non-specific lipid transfer proteins gene, or a ribosome-inactive protein gene and a non-specific lipid transfer protein gene.