Study of fungal lectins as potential bio-pesticides to control aphid pests

In the present study, direct effects of two fungal lectins, Xerocomus chrysenteron lectin (XCL) and Penicillum chrysogenum lectin (PCL) in comparaison with a lectin from plant origine, Canavalia ensiformis agglutinin (ConA) were evaluated in laboratory conditions. These experiments were performed on two economically important insect belonging to the order of Homoptera, the peach potato aphid (Myzus persicae.) and pea aphid (Acyrthosiphon pisum), via artificial diets. XCL recombinant showed high hemagglutining and aphicide activity. Significant effects of XCL on M. persicae biological parameters such as survival, weight, duration of development time and fecundity were observed when it fed on artificial diet content of 0.1% XCL in comparison with ConA. High significant A. pisum mortality was observed when it fed on artificial diets incorporating 0.1% XCL or 0.1% ConA. By SDS-PAGE analyses, the presence of XCL and ConA in digestive tracts and haemolymph was observed for both species which fed respectively on diets containing XCL or ConA, while a weak trace of honeydew was only observed in A. pisum samples. Both, immunolocalization and ligand blot analyses confirmed the presence of the XCL in these three parts of A. pisum and in the digestive tracts of M. persicae only. We purified a new lectin from fungus, Penicillum chrysogenum namely, PCL through gel filtration (FPLC). This lectin showed to have high aphicide activity toward M. persicae, when compared with the refference lectin (ConA). Therefore, this lectin would be one of the promising entomotoxic proteins to a wide range of insect pests.