Expression of Aedes trypsin-modulating oostatic factor on the virion of TMV: A potential larvicide

*Florida Medical Entomology Laboratory, University of Florida–Institute of Food and Agricultural Sciences (IFAS), 200 Ninth Street Southeast, Vero Beach, FL 32962-4699;
^‡Citrus Research and Education Center, University of Florida–IFAS, 700 Experiment Station Road, Lake Alfred, FL 33850;
^¶Indian River Research and Education Center, University of Florida–IFAS, 2199 South Rock Road, Fort Pierce, FL 34945;
Departments of ^‖Chemistry and
**Chemistry and Pathology, University of Virginia, Charlottesville, VA 22904;
^††Department of Pharmacology, Catholic University of Leuven, Van Evenstraat 4, B-3000 Leuven, Belgium; and
^§§Zoological Institute, Catholic University of Leuven, Naamsestraat 59, B-3000 Leuven, Belgium

Communicated by Lonnie O. Ingram, University of Florida, Gainesville, FL, July 21, 2006 (received for review October 9, 2005)

Abstract

We report the engineering of the surface of the tobacco mosaic virus (TMV) virion with a mosquito decapeptide hormone, trypsin-modulating oostatic factor (TMOF). The TMV coat protein (CP) was fused to TMOF at the C terminus by using a read-through, leaky stop codon that facilitated expression of CP and chimeric CP-TMOF (20:1 ratio) that were coassembled into virus particles in infected Nicotiana tabacum. Plants that were infected with the hybrid TMV RNA accumulated TMOF to levels of 1.3% of total soluble protein. Infected tobacco leaf discs that were fed to Heliothis virescens fourth-instar larvae stunted their growth and inhibited trypsin and chymotrypsin activity in their midgut. Purified CP-TMOF virions fed to mosquito larvae stopped larval growth and caused death. Because TMV has a wide host range, expressing TMV-TMOF in plants can be used as a general method to protect them against agricultural insect pests and to control vector mosquitoes.

Footnotes

^†To whom correspondence should be addressed. E-mail: dobo{at}mail.ifas.ufl.edu
↵ ^§Present address: Fraunhofer USA CMB, 9 Innovation Way, Suite 200, Newark, DE 19711.
↵ ^‡‡Present address: Tibotec BVBA, Gen. De Wittelaan 11B 3, B-2800 Mechelen, Belgium.
Author contributions: D.B., W.O.D., C.A.P., D.F.H., and A.D. designed research; D.B., S.R., C.A.P., D.A.I., T.J.M., J.S., and H.L.D. performed research; D.B., W.O.D., C.A.P., D.F.H., H.L.D., and A.D. analyzed data; and D.B. wrote the paper.
Conflict of interest statement: D.B. and A.D. have patents on the TMOF technology through the University of Florida.
Abbreviations:

CP,

coat protein;

HSD,

honestly selectively different;

TMOF,

trypsin-modulating oostatic factor;

TMV,

tobacco mosaic virus.