Catálogo de Investigaciones | 2013-2014

CI ENCIAS 56 Genetic Variation Assessment of the Killer Toxin Gene of Debaryomyces Hansenii Strains, as Potential Bio- Control Agent against Penicillium Digitatum in Citrus Crops Citrus crops are affected by Penicillium spp ., a post harvest pathogen. This infection represents a loss of millions of dollars to the citrus industry. A killer toxin produced by the halotolerant yeast Debaryomyces hansenii , has a great potential as a bio-control agent against this pathogenic fungus. Some strains of D. hansenii have shown a more stable antagonistic activity against the pathogen. A library of twenty-four strains of D. hansenii has been studied to assess genetic variation of the killer toxin gene and correlate this variation to the effectiveness of the killer toxin. Amplification and sequencing of 807 bp of the killer toxin gene of nine D. hansenii strains was performed. The PCR products of these strains have conservation scattered among different chromosomes of D. hansenii’s genome. The D. hansenii strain BCS-006 which had proven to be the most efficient against the pathogen showed the greatest genetic variation among all the different strains. It seems the inhibitory activity of D. hansenii’s killer toxin might be affected by the variation in residues. These variations are crucial due to their position near the core of the protein sequence. Recently more D. hansenii strains have been screened for their antifungal activity and found to be excellent candidates for further exploration of their bio-control potential. Chemical solutions have been newly developed to combat postharvest diseases but one of their main components have been classified as a possible human carcinogen, giving our project a great importance because of our biological control approach. luis i. rosa, héctor m. rodríguez y darlene olivera proyecto c.e.i.b.a. mentor: dra. hna. nancy arroyo gonzález debaryomyces hansenii penicillium citrus