Overexpression of a harpin-encoding gene popW in tobacco enhances resistance against Ralstonia solanacearum

PopW, a harpin protein identified from Ralstonia solanacearum, has multiple beneficial effects in plants, promoting plant growth and development, increasing crop yield, and inducing resistance to pathogens. Tobacco plants transformed with popW, the PopW-encoding gene, exhibited a promoted growth rate and enhanced resistance to Tobacco mosaic virus (TMV). Here, it is documented that the transgenic tobacco plants overexpressing popW exhibited a higher resistance to R. solanacearum YN10 infection compared with that of the wild-type plants. In the popW-expressing tobacco lines, an enhanced H2O2 accumulation and hypersensitive reaction (HR) were activated in the inoculated site. In addition, the resistance was accompanied with increased transcripts in numbers of genes related to defense (including HR), reactive oxygen species (ROS) scavenging, and salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) production. These results suggest that popW acted as positive regulator in tobacco resistance against R. solanacearum via modulation of SA-, JA-, and ET-mediated signaling pathways. We report for the first time that the expression of a harpin-encoding gene in vivo improved plant resistance to R. solanacearum.