Resistance to both aphids and nematodes in tobacco plants expressing a Bacillus thuringiensis crystal protein

Bacillus thuringiensis (Bt) and its crystal toxin or δ-endotoxins (Cry) offer great potential for the efficient control of crop pests. A vast number of pests can potentially infect the same host plant, either simultaneously or sequentially. However, no effective Bt-Cry protein has been reported to control both aphids and plant parasitic nematodes due to its highly specific activity.

Our study indicated that the Cry5Ba2 protein was toxic to the green peach aphid Myzus persicae, which had a median lethal concentration (LC₅₀) of 9.7 ng μL^-1 and fiducial limits of 3.1-34.6 ng μL^-1. Immunohistochemical localization of Cry5Ba2 revealed that it could bind to the apical tip of microvilli in midgut regions. Moreover, transgenic tobacco plants expressing Cry5Ba2 exhibited significant resistance to Myzus persicae, as evidenced by reduced insect survival and impaired fecundity, and also intoxicated the Meloidogyne incognita as indicated by a decrease in galls and progeny reproduction.

In sum, we identified a new aphicidal Bt toxin resource that could simultaneously control both aboveground and belowground pests, thus extending the application range of Bt-based strategy for crop protection. © 2024 Society of Chemical Industry.