Aflatoxins produced by Aspergillus flavus and A. parasiticus are the most toxic and potent natural carcinogens known to date. A. flavus is also an opportunistic pathogen that is capable of infecting plants, animals and humans. Infection in preharvest crops such as corn, cotton, peanut and tree nuts by A. flavus not only reduces yield but also renders them unsafe for human and animal consumption due to aflatoxin contamination. The economic losses due to the contamination are staggering. The primary objectives of our A. flavus genomics program are to reduce and eliminate aflatoxin contamination in food and feed through validation of known genes involved in aflatoxin formation and fungal infection and identification of novel targets. To this end, we performed functional genomics studies in A. flavus and the non-toxigenic and non-pathogenic A. oryzae strain using three different types of microarrays (amplicon, oligo and Affymetrix arrays). Gene expression profiling demonstrated that genes involved in aflatoxin production are differentially expressed in A. flavus compared to A. oryzae under conditions that support aflatoxin formation and mimic infection. In addition, genes encoding cellulosic degrading enzymes and spore surface proteins are differentially expressed in A. flavus, but not in A. oryzae. This suggests that these proteins could play a key role in fungal infection. A. flavus is a saprobe having the ability to survive in the natural environment by extracting nutrition from plant debris and dead insects. The nature of its survivability could be related to the mechanisms of fungal pathogenicity. Functional characterization of these enzymes can help devise strategies to control fungal infection of agricultural crops.
Full conference title:
9th EUROPEAN CONFERENCE ON FUNGAL GENETICS
- ECFG 9th (2008)