African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5211

Full Length Research Paper

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

Theo Rapulana and Gustav Bouwer*
School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa.
Email: [email protected]

  •  Accepted: 07 February 2013
  •  Published: 02 April 2013


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 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.


Key words: Eldana saccharina, Bacillus thuringiensis, Cry protein, toxicity,Gluconacetobacter diazotrophicus, recombinant strain.