Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: July 1, 2011
Publication Date: August 6, 2011
Citation: Palencia, E., Mitchell, T., Riley, R.T., Hinton, D.M., Snook, M.E., Bacon, C.W. 2011. Endophytic associations and production of mycotoxins by the Aspergillus section Nigri species. American Phytopathological Society and the International Plant Protection Congress (IPPC) Joint Meeting. August 6-10, 2011. Honolulu, HI. Technical Abstract: The filamentous fungi of the Aspergillus section Nigri (black aspergilli) are considered plant pathogens of maize (Zea mays) and peanuts (Arachis hypogaea) where they can cause similar disease symptoms as Fusarium verticillioides, such as seedling blight. However, the main concern with black aspergilli is their ability to produce carcinogenic mycotoxins such as ochratoxin A (OTA) and the fumonisins (FB1, FB2, and FB3). Our preliminary work indicated that these fungi were endophytes of maize. The first aim of our research was to provide evidence of endophytic associations between maize using yellow and red fluorescent protein-labeled strains of A. niger var niger (yfp) and A. carbonarius (rfp). The identities of the fungi were determined using a repetitive-sequence-based DNA method. This study revealed that both Aspergillus species had similar host colonization patterns in maize as endophytes. The second aim was to determine mycotoxin production by these species. We determined the ability of 167 field isolates to synthesize OTA, FB1, FB2, and FB3 in maize kernels as natural substrate and that of the species isolated, only 10% of A. niger var niger strains produced OTA. However, almost 60% of the field isolates were able to produce the fumonisins. Our results are the first to indicate that black aspergilli associated with field maize in the United States are able to produce carcinogenic compounds, and are potential threats to human and domestic animal health.