Phylogeny, Plant Species, and Plant Diversity Influence Carbon Use Phenotypes Among Fusarium Populations in the Rhizosphere Microbiome

Carbon use by microorganisms in the rhizosphere microbiome has been linked to plant pathogen suppression and increased mineralization of soil nutrients for plant uptake; however, factors that influence carbon use traits are poorly understood for most microbial groups. This work characterized the relationships of phylogeny, plant species, and plant diversity with carbon use among fungi in the genus Fusarium from rhizosphere soil. Eighty-four randomly collected Fusarium isolates were cultured from the rhizosphere of the perennial plants Lespedeza capitata and Andropogon gerardii, maintained as long-term monocultures or growing in 16-plant species polycultures. For each isolate, a portion of the RPB2 locus was sequenced for phylogenetic analyses and growth on 95 carbon substrates was measured using Biolog SF-P2 plates. Similarity in carbon use among isolates decreased with increasing genetic distance and there were differences in niche width (i.e., number of carbon substrates used) and growth on preferred su...