Construction of a bioinsecticidal strain of Pseudomonas fluorescens active against the sugarcane borer, Eldana saccharina

Abstract

A cryIA(c) gene was cloned from a native Bacillus thuringiensis strain showing activity against the sugarcane borer, Eldana saccharina. The sequence of the cloned gene was very similar to that of the B. thuringiensis subsp. kurstaki HD-73 cryIA(c) gene. The gene was introduced into an isolate of Pseudomonas fluorescens, capable of colonizing sugarcane, on two broad-host- range plasmids, pDER405 and pKT240, having copy numbers of 13 and 28, respectively. By using the Omegon-Km vector, the cry gene was introduced into the chromosome of P. fluorescens isolate 14. Bioassays on eldana larvae showed that the strain carrying the gene integrated into the chromosome was as toxic as one carrying it on pKT240. Glasshouse trials indicated that sugarcane treated with P. fluorescens 14::Omegon-Km-cry were more resistant to eldana damage than untreated sugarcane was.