Generation of an orally infective recombinant AgMNPV with improved bioinsecticidal activity

HAASE, S., S; FERRELLI, M. L.; SALVADOR R; BERRETTA M. F.; SCIOCCO-CAP, A. & ROMANOWSKI

Halifax

Congreso; 2011 International Congress on Invertebrate Pathology and Microbial Control & 44th Annual Meeting of the Society for Invertebrate Pathology; 2011

SIP

AgMNPV (Anticarsia gemmatialis Nucleopolyhedrovirus), the most widely used viral bioinsecticide, has  been successfully applied for control of its host, the velvetbean caterpillar (Anticarsia gemmatalis). However, the use of this baculovirus presents among its limitations a slow speed of kill  in temperate climates.  In this context, our group developed a system for the genetic modification of AgMNPV, based on double homologous recombination between the linearized viral genome and a transfer vector.  Recombinant viruses obtained using transfer vectors previously constructed provided adequate expression levels of heterologous gene. However, propagation of the recombinants in cell culture resulted in viruses not infective per os, probably due to genetic rearrangements. Therefore a new generation of transfer vectors was constructed. The system was first checked using a new vector bearing the green fluorescent protein gene (egfp). A rAgMNPV-egfp was generated and its oral infectivity and eGFP expression were confirmed using 3rd instar  A. gemmatalis  larvae. Using this system an insect-selective neurotoxin (tox34) gene from Pyemotes tritici was used to construct rAgMNPV-tox34. Expression of the toxin by the virus causes a reduction in the time required to kill the host insect. Both rAgMNPV were characterized by PCR, restriction pattern analysis and SDS-PAGE of infected cells. In conclusion, rAgMNPV-egfp can be used as a tool for basic research and rAgMNPV-tox34 exhibits an increased biopesticidal activity.