Molecular interactions of CRY1 and VIP3 proteins in the control of lepidopterans in sugarcane

Author(s)

Ana Rita Nunes Lemes

• Document type: Doctoral Thesis
• Press: Jaboticabal. 2016-03-14.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
• Defense date: 2016-02-10
• Advisor: Janete Apparecida Desidério

Abstract

The biotechnological potential of Cry and Vip proteins from the bacterium Bacillus thuringiensis is widely known. However, the evolution of pest resistance is a major threat to long-term control of insect pests by transgenic plants with toxins of this bacterium. Studies have reported the need to slow down the evolution of resistance and, among the possibilities, the use of more than one gene in the construction of transgenic plants is shown to be efficient. Thus, it is important to look for new genes with different modes of action, and select those with different entomotoxic activity to Diatraea flavipennella and Elasmopalpus lignosellus, which are secondary and potential sugarcane pests. Therefore, Cry1 and Vip3 proteins were expressed in Escherichia coli and the toxicity was verified by bioassays using neonate larvae of both species of the insect pests. The proteins were purified, solubilized, and activated with trypsin and biotinylated. The BBMVs (Brush Border Membrane Vesicles) were prepared using the intestines of the two species to perform the homologous and heterologous competition assays. Considering the LC50, the Cry1Ac and Vip3Aa proteins were the most effective in controlling the insect pests in this study. The binding assays showed that there was interaction between the proteins and the receptors of the two species of larvae. The heterologous competition assays showed no competition between Cry1 and Vip3 proteins for the same binding sites for both species studied. The results suggest that the combination of Cry1Aa or Cry1Ac with Vip3Aa for future events of sugarcane generation genetically modified could contribute to resistance management for these insects. (AU)

• FAPESP's process: 12/19265-1 - Analysis of the molecular interactions of Bacillus thuringiensis toxins targeting the management of resistance to insect pests in sugar cane.
• Grantee: Ana Rita Nunes Lemes
• Support Opportunities: Scholarships in Brazil - Doctorate