Improved insecticidal activity of a genetically modified baculovirus expressing the immunosuppressive CrV1 protein from a polydnavirus against Spodoptera exigua

ABSTRACT

Recombinant baculoviruses could be used as biological insecticides through the introduction and expression of exogenous genes (such as those coding for proteins) that interfere with metabolism, metamorphosis (toxins, hormones, and enzymes), and immune system of the insects. The CrV1 secreted protein of Cotesia rubecula polydnavirus (PDV) is responsible for the actin depolymerisation in haemocytes and the abolishment of immune functions such as phagocytosis and cell spreading, thus allowing the successful embryonic development of the parasitoid wasp. CrV1 cDNA was cloned into C6 strain of Autographa californica multiple nucleopolyhedrovirus (AcMNPV-C6-CrV1) under p10 promoter to construct a recombinant virus. The recombinant virus was then tested against the insect pest Spodoptera exigua. The recombinant virus expressing CrV1 protein showed significantly lower LC₅₀ and shorter LT₅₀ as compared with the AcMNPV-C6 wild-type virus. The potential of recombinant baculoviruses expressing PDV genes in relation to their virulence is discussed.

KEYWORDS:

• Polydnavirus
• CrV1 protein
• baculoviruses
• Spodoptera exigua

Acknowledgements

We thank Drs Félix Ortego and Gema P. Farinós from Centro de Investigaciones Biológicas, Madrid, Spain for the critical review of an earlier version of the manuscript. Dr Primitivo Caballero-Murillo from Universidad Pública de Navarra, Spain for provided us with the AcMNPV-C6 wild-type baculovirus. The CrV1 cDNA was provided by Dr Sassan Asgari from the University of Queensland, Australia. Dr Monsuru A. Adeleke from the Department of Biological Sciences, Osun State University, Nigeria revised a later version of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The present work was supported by the Secretaría de Investigación y Posgrado del Instituto Politécnico Nacional (IPN), México [grant number 20131463]. Mario A. Rodríguez-Pérez holds a scholarship from the Comisión de Operación y Fomento de Actividades Académicas del IPN. Lihua Wei holds a scholarship from Consejo Nacional de Ciencia y Tecnología (CONACYT)-México (Reference No. 391167). Mario A. Rodríguez-Pérez also holds a sabbatical scholarship from CONACYT-Mexico (Reference No. 246116), which allowed the completion of the present article.