Characterization of potential native Bacillus thuringiensis strains isolated from insect cadavers against cotton aphid Aphis gossypii glover (Hemiptera: Aphididae) Rajashekhar Mandla, Mittal Anubhav, Dharavath Veeranna, Kalia Vinay K.* Division of Entomology, ICAR-Indian Agricultural Research Institute, New Delhi-110012 *Email: vkalia@iari.res.in
Online published on 27 July, 2018. Abstract The cotton aphid Aphis gossypii is one of the important sucking pests of cotton. Studies on toxicity of Bacillus thuringiensis (Bt) against hemipterans are rare. In the present study, five native Bt strains viz., VKK-AC1, VKK-AC2, VKK-BB1, VKK-BB2 and VKK-PX1 isolated from insect cadavers showed consistent mortality of adults of A. gossypii in pre-solubilized, solubilized as well as in trypsinized form. The LC50 values for these showed that VKK-AC2 and VKK-BB1 were the most effective followed by VKK-PX1 and VKK-BB2. SDS-PAGE gel analysis of toxins showed 20–135 kDa bands in pre-solubilized and 20–106 kDa in solubilized form. As regards trypsinized form protein profiling of all the five native Bt strains showed two bands each in the range of 60–66 kDa which were highly toxic. All the shortlisted Bt strains viz., VKK-AC1, VKK-AC2, VKK-BB1, VKK-BB2 and VKK-PX1 amplified novel band of 275–292 bp with cry4 gene specific primers. Top Keywords Bacillus thuringiensis, strains, Aphis gossypii, adults, cry proteins, cry gene, pre-solubilized, solubilised, trypsinized forms, LC50 values, protein profile. Top |