Beyond host specificity: the biotechnological exploitation of chitolectin from teratocytes of Toxoneuron nigriceps to control non-permissive hosts

The virulence factors (VF) that parasitoids use to regulate the growth and development of their hosts have potential as new events in transgenic plants. VFs are promising candidates for biotechnological exploitation and implementation of pest-control tools to meet the world’s demand for food in 2100, while sustainably increasing agricultural production. However, VFs have not been used in commercial transgenic plants, since they are thought to target only a narrow range of insects, due to the parasitoid host specialization. We investigated the potential of chitolectin (TnChit), produced by the teratocytes of Toxoneuron nigriceps (Viereck) (Hymenoptera: Braconidae), as a transgenic event to control several non-permissive hosts: Chrysodeixis includens (Walker), Spodoptera albula (Walker), Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae), Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) and Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Third instars of C. includens, S. albula and S. frugiperda had lower survival and probability of molting on TnChit-modified plants than on control plants. The nutritional indices of S. frugiperda were also altered. Larval survival and pupal weight of males of T. absoluta were reduced on transgenic plants. Adult emergence of B. tabaci was also reduced. The expression of the TnChit gene differed in the transformation events obtained and was consistent with the biological effects observed. The effects of TnChit on non-permissive hosts demonstrate the potential of the virulence factors that parasitoids employ in host regulation, as a source of new genes in plant transformation for control of insect pests.