DEVELOPMENT OF A RECOMBINANT BACULOVIRUS EXPRESSING A MODIFIED JUVENILE-HORMONE ESTERASE WITH POTENTIAL FOR INSECT CONTROL

Baculovirus insecticides are receiving renewed attention as insect pes t control agents following the development of fast-acting recombinant baculoviruses. Here we report on the construction and biological activ ity of a recombinant baculovirus derived from the nuclear polyhedrosis virus of Autographa californica which expresses a modified form of ju venile hormone esterase (JHE). The serine at the catalytic site of the JHE has been mutated to a glycine residue so that the protein does no t degrade JH. The recombinant baculovirus expressing this modified for m of JHE, named AcJHE-SG, has enhanced activity against lepidopteran l arvae. Lethal times of the recombinant are 20 to 30% lower than for th e wild type virus, and a 66% reduction in feeding damage caused by inf ected larvae is observed. This result is comparable to the best recomb inant baculovirus developed to date, AcAalT, which expresses an insect -selective scorpion toxin. The potential of these recombinant viruses for commercialization as insecticides is discussed. Bioassays of AcJHE -SG in conjunction with anti-JH agents indicate that the virus is not killing by an anti-JH mechanism. Larvae apparently die from contractio n-paralysis, or disruption of the normal sequence of events at the mol t. (C) 1995 Wiley-Liss, Inc.