Assessment of Insect Host Range Susceptible for Toxin Produced by Fusarium semitectum to resist Sucking Pests in Transgenic Plants

Abstract

Transgenic plants are developed mainly to resist defoliators. Bacillus thuringiensis (Bt) is the bacterium widely used to develop transgenic plants expressing resistance against defoliators especially caterpillars, maggots and grubs. However, such crops cannot escape the attack of sucking insect pests and therefore always required systemic insecticides for their effective management. Getting free from spraying of such toxic pesticides on transgenic plants, the gene that develops resistant in plants to sucking pests has also to be incorporated. Obtaining such resistant gene will be another milestone to the development of transgenic plants with resistance to defoliators as well as sucking pests. The mycopathogen, Fusarium semitectum was infective on number of sucking pests viz: chilli thrips (Scirtothrips dorsalis), aphid (Aphis gossypii), sugarcane wooly aphid (Ceratavacuna lanigera), and spiraling whitefly (Aleyrodicus dispersus). The toxin of F. semitectum caused total mortality on these insects. It was found harmless and non-infective to Lepidopteran insects viz: silkworm (Bombyx mori), armyworm (Helicoverpa armigera), cutworm (Spodoptera litura). Pathogenicity studies at the laboratory confirmed that E semitectum was safe to insects belonging to Lepidoptera, Diptera and Hymenoptera. This selective nature will be helpful to widen its application in those places, where sericulture and apiculture industries are established. Due to this specificity it is possible to consider the gene of the fungus to be incorporated into the plants to induce resistance against sucking pests. This opens a new avenue towards incorporation of the gene to build up resistance in transgenic plants against sucking pests of crops.