Abstract：PopW from Ralstonia solanacearum is a member of the harpin protein family, eliciting hypersensitive cell death in non-host plants, inducing disease resistance in plants and enhancing plant growth. To achieve secretory expression of PopW protein in Bacillus subtilis, we constructed recombinant expression vector pHTPOW, which carried the p43 promoter, a signal peptide element of nprB, and the full length PopW gene. The expression of PopW in the genetically modified strains was confirmed by SDS-PAGE and Western bloting analysis. In vitro test showed that on the 24 and 48 h after treated with the genetically modified strain BsW, the J2 mortality rates of Meloidogyne incognita were 53.4% and 79.6%, respectively. In the green house trials, the number of eggs and galls reduced significantly 42-days after tomato (Lycopersicon esculentum) treatment with the transgenic strain BsW and the biocontrol efficacy reached 60.0%. The genetically-modified bacteria strain which enhances plant growth and inhibits nematodes activity offers a new promising perspective on the reasearch and development of new microbial pesticides.
