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Title: Allelopathic compound production influences fungal endophyte community assembly and establishment of a seed-borne primary colonizer in maize

Author
item SAUNDERS, MEGAN - UTRONTO,MISSISSAUGA,CAN
item Glenn, Anthony - Tony
item KOHN, LINDA - UTRONTO,MISSISSAUGA,CAN

Submitted to: International Allelopathy Congress
Publication Type: Abstract Only
Publication Acceptance Date: 6/27/2008
Publication Date: 9/21/2008
Citation: Saunders, M., Glenn, A.E., Kohn, L.M. 2008. Allelopathic compound production influences fungal endophyte community assembly and establishment of a seed-borne primary colonizer in maize. International Allelopathy Congress. September 21 - 26, 2008. Saratoga Springs, NY.

Interpretive Summary: Abstract - no summary required.

Technical Abstract: Maize was used to assess the influence of three biotic factors on fungal endophyte community assembly: production of host allelopathic compounds, proximity of a host to a neighboring plant producing allelopathic compounds, and presence of a primary colonizer tolerant to these compounds. Maize has been selectively bred to produce high concentrations of benzoxazinoids (BXs), some byproducts of which are toxic to fungi, bacteria, arthropods and plants. To determine the influence of BX production on endophyte communities, fields were planted with maize genotypes differing in their ability to produce BXs. Fungal endophyte community members were identified and tested for tolerance to a toxic BX-byproduct, 2-benzoxazolinone (BOA). Species diversity and distribution of BOA tolerance levels in communities was determined. In seedling roots and mature leaves, the community proportion with low tolerance to BOA was significantly greater in BX non-producers (BX-) than in producers (BX+). Mean abundance of Fusarium species, including agents of animal toxicosis and corn diseases, was up to 35 times higher in mature leaves of BX+ than in BX- plants. Next, we compared communities from BX- plants that were either planted in plots with two BX+ genotypes, or in a BX- monoculture. Mean endophyte abundance and species diversity were greater in monoculture than in triculture. Finally, the effect of a seed-borne endophyte on communities was investigated. Fields were planted with BX+ and BX- genotypes that were sterilized or inoculated with Fusarium verticillioides, a maize endophyte able to detoxify BOA. Results indicate that F. verticillioides facilitates colonization by closely related species in BX+, but not BX- plants. Collectively, results suggest that increased colonization of maize by Fusarium may be an outcome of selective breeding for BX production. Production of BXs, spatial proximity of BX- hosts to BX+ plants, and presence of F. verticillioides as a primary colonizer in seed significantly altered endophyte community assembly.