VIP3A, A NOVEL BACILLUS-THURINGIENSIS VEGETATIVE INSECTICIDAL PROTEINWITH A WIDE SPECTRUM OF ACTIVITIES AGAINST LEPIDOPTERAN INSECTS

A novel vegetative insecticidal gene, vip3A(a), whose gene product sho ws activity against lepidopteran insect larvae including black cutworm (Agrotis ipsilon), fall armyworm (Spodoptera frugiperda), beet armywo rm (Spodoptera exigua), tobacco budworm (Heliothis virescens), and cor n earworm (Helicoverpa zea) has been isolated from Bacillus thuringien sis strain AB88. VIP3-insecticidal gene homologues have been detected in approximate to 15% of Bacillus strains analyzed. The sequence of th e vip3A(b) gene, a homologue of vip3A(a) isolated from B. thuringiensi s strain AB424 is also reported. Vip3A(a) and (b) proteins confer upon Escherichia coli insecticidal activity against the lepidopteran insec t larvae mentioned above. The sequence of the gene predicts a 791-amin o acid (88.5 kDa) protein that contains no homology with known protein s. Vip3A insecticidal proteins are secreted without N-terminal process ing. Unlike the B. thuringiensis delta-endotoxins, whose expression is restricted to sporulation, Vip3A insecticidal proteins are expressed in the vegetative stage of growth starting at mid-log phase as well as during sporulation. Vip3A represents a novel class of proteins insect icidal to lepidopteran insect larvae.