Ana Rita Nunes Lemes , Suzana C. Marucci , Juliana R. V. Costa , Eliane C. C. Alves , Odair A. Fernandes , Manoel Victor F. Lemos , Janete A. Desidério

Univ Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 14884-900, Jaboticabal, São Paulo, Brazil
Author    Correspondence author
Bt Research, 2015, Vol. 6, No. 1   doi: 10.5376/bt.2015.06.0001
Received: 24 Oct., 2014    Accepted: 29 Jan., 2015    Published: 31 Jan., 2015

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The bacterium Bacillus thuringiensis (Berliner) is an important entomopathogen that can replace chemical pesticides in crops. In addition to the endotoxins found in B. thuringiensis, new proteins have been studied recently, such as Vip and Chitinase, which can enhance toxic effects by acting synergistically. Thus, the objectives of this work were to select new B. thuringiensis isolates carrying cry1Fa, vip3Aa, and chi; to verify polymorphisms based on PCR-RFLP  analysis; and to evaluate mortality and existence of synergistic effects of these genes on Spodoptera frugiperda larvae. A total of 114 isolates were subjected to screening via PCR to detect the vip3Aa, cry1Fa, and chi genes. Neonatal larvae of S. frugiperda were bioassayed using isolates containing one, two or all three genes and were compared to the standard strains. The PCR-RFLP analysis showed the absence of polymorphisms in these gene regions. The B. thuringiensis isolates from different regions of Brazil contained different combinations of the cry1Fa, vip3Aa, and chi genes. The presence of vip3Aa appeared to act synergistically with chi, and the combination of all three genes caused increased mortality in S. frugiperda larvae. Due to their insecticidal potential, these isolates are a prospective source of genes that can be used to genetically modify crops to increase the efficacy of pest control.

Biological control; Vip3Aa; Cry1Fa; chitinase