Abstract: The chitinase gene of baculovirus is the gene that is not essential for the virus replication. It is expressed in the late phase of the virus replication in insect cells, and it is highly conservative. The chitinase contains three functional regions: N-terminal secretion signal peptide, central active region that includes the active site of family 18 chitinases and a functional C-terminal endoplasmic reticulum (ER)-retention sequence. The enzyme possesses high performance of both exo- and endo-chitinase activity, which can hydrolyze inherent chitin in insect body, and promote liquefaction of the host after death. The chitinase may also serve as a molecular chaperone of pro-V-Cath, the precursor of V-Cath, for its proper folding and transportation in the ER. It has an influence on the polyhedra releasing and cell lysis. The chitinase is also relevant to the baculovirus infection. Phylogenetic analyses indicate that baculovirus acquires the chitinase gene from bacterium via horizontal gene transfer, but insect chitinase gene may directly come from baculovirus. For biological control of pests, the baculovirus chitinase can control insect pests as an insecticide, or work together with Bacillus thuringiensis or a baculovirus as its potentiator; the baculovirus chitinase gene can also be introduced into plants to get the transgenic plants that increase resistance against herbivorous pests and fungal pathogens without affecting non-target insects. The baculovirus chitinase ER-retention motif was deleted or modified, or heterologous chitinase was introduced into the baculovirus genome, which made the biological activity of the recombinant virus enhanced. Deletion of the chitinase and v-cathepsin genes from the baculovirus expression vector through genetic engineering has a positive effect on the integral membrane and secreted proteins.

Key words: Biological control, baculovirus chitinase, function, origin, synergistic action, insecticidal activity, application