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ARS Home » Southeast Area » Dawson, Georgia » National Peanut Research Laboratory » Research » Publications at this Location » Publication #310491
Title: Population dynamics of Aspergillus flavus following biocontrol treatment of corn

Author
item OLARTE, R - North Carolina State University
item Horn, Bruce
item WORTHINGTON, C - North Carolina State University
item LEWIS, M - North Carolina State University
item SINGH, R - North Carolina State University
item HEINIGER, R - North Carolina State University
item OJIAMBO, P - North Carolina State University
item CARBONE, I - North Carolina State University

Submitted to: Plant Pathology International Congress
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/2013
Publication Date: 8/1/2013
Citation: Olarte, R.A., Horn, B.W., Worthington, C.J., Lewis, M.H., Singh, R., Heiniger, R.W., Ojiambo, P.S., Carbone, I. 2013. Population dynamics of Aspergillus flavus following biocontrol treatment of corn. Plant Pathology International Congress.

Interpretive Summary: none required

Technical Abstract: Aspergillus flavus is a fungal pathogen of many agronomically important crops worldwide. We sampled A. flavus strains from a cornfield in Rocky Mount, North Carolina, over a period of two years. The field was planted in 2010 and plots were inoculated at tasselling with either AF36 or NRRL 21882 (=Afla-Guard) biocontrol strains, both of which are mating type MAT1-2. Subsequently, toxigenic strain NRRL 3357 (MAT1-1) was applied to all plots, including control plots not inoculated with biocontrol strains. Sclerotia were collected from infected corn ears at harvest and ninety single-ascospore isolates were obtained from ascocarps originating from plots treated with AF36 and NRRL 21882. In addition, eighty A. flavus isolates were collected from soil one month after planting (before biocontrol application) and one and two years after biocontrol application. PCR revealed grouping of isolates into three distinct mating-type classes: MAT1-1, MAT1-2 and MAT1-1/MAT1-2. A significant proportion (54%) of isolates sampled prior to biocontrol treatments and 39% of isolates obtained from ascospores were heterokaryotic for mating type (MAT1-1/MAT1-2). The vertical transmission of MAT1-1/MAT1-2 to progeny ascospore isolates suggests that heterokaryosis can be maintained in subsequent generations. The population genetic structure before and after the application of biocontrol treatments will be discussed. The potential for the biocontrol strain to undergo sexual reproduction and the degree of relatedness of the biocontrol strain to the predominant indigenous lineage may influence the long-term success of a biocontrol strain. These findings will be instrumental in the selection of strains for use in next-generation biocontrol strategies.