Toxicity to Eldana saccharina of a recombinant Gluconacetobacter diazotrophicus strain carrying a truncated Bacillus thuringiensis cry1Ac gene

摘要

The stalk borer?Eldana saccharina?Walker?(Lepidoptera: Pyralidae) is a serious pest of sugarcane in Africa. Because?E. saccharina?larvae feed inside the stem of sugarcane, expression of insecticidal?Bacillus thuringiensis?Cry proteins in sugarcane endophytes, such as?Gluconacetobacter diazotrophicus, would enable the Cry proteins to be produced in the feeding zones of burrowing larvae. To evaluate the potential of using a Cry-expressing?G. diazotrophicus?strain for the control of?E. saccharina,?a truncated?B. thuringiensis cry1Ac?gene was cloned into?a?G. diazotrophicus?strain and the toxicity of the recombinant strain to?E. saccharina?larvae was evaluated. Bioassays showed that the recombinant?G. diazotrophicus?strain carrying the cloned?cry1Ac?gene caused significantly higher?E. saccharina?mortality and larval growth inhibition than the non-recombinant?G. diazotrophicus?strain. This study sets a foundation for?E. saccharinacontrol strategies that are based on the expression of truncated?cry1Ac?genes in?G. diazotrophicus.