|Dill-macky, Ruth - University Of Minnesota|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/3/2018
Publication Date: N/A
Technical Abstract: Manipulating the microbiome of wheat seeds and heads may contribute to control of Fusarium head blight and mycotoxin accumulation in grain, which creates a food safety hazard. With the aim of identifying novel management targets, we looked for correlations between Fusarium biomass (assessed by qPCR) or deoxynivalenol (DON) content (measured by gas chromatography) and characteristics of the microbial communities inhabiting wheat grain (community profiles generated by amplicon sequencing). We anticipate that other microorganisms inhabiting the wheat seed could lessen DON content by reducing Fusarium biomass, or by lowering DON production per unit Fusarium biomass. Samples were collected from a common wheat variety planted across a mist irrigated nursery in St. Paul, Minnesota, in each of two successive years. Individual seeds were analyzed in an attempt to approach the fine spatial scale at which microbial communities are organized. Out of 96 seeds tested in 2016, both Fusarium and DON were present at measurable levels in every seed tested. Out of 192 seeds tested in 2017, DON was detected in only 27% of seeds. Relationships between Fusarium biomass and DON content, where both were measurable, were strong (r2=0.78 in 2016 and 0.72 in 2017; P<0.001). Microbiome profiles generated through amplicon sequencing (partial 16S rRNA genes for bacteria, ITS1 for fungi) revealed that for certain taxa, abundance among seeds was correlated with pathogen biomass or with the deviation from the expected relationship between Fusarium biomass and DON content. Seeds collected from the same head harbored microbiomes that were on average more similar to each other than seeds collected from different heads. This indicates some biogeographic patterning to the assembly of the wheat spike microbiome. The microbial communities associated with wheat seeds may substantially impact the development of Fusarium head blight and the accumulation of mycotoxins in grain. With rigorous development, the microbiome of wheat heads may become a target for agricultural management.