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Novel Magnaporthales fungi pathogenic to switchgrass and turfgrasses

Jing Luo: Rutgers University

<div>About 50% of species in the fungal order Magnaporthales are pathogens of monocotyledon plants, including the rice blast fungus <em>Pyricularia oryzae</em> (syn. <em>Magnaporthe oryzae</em>), the take-all pathogen of cereals <em>Gaeumannomyces graminis </em>(syn. <em>Gaeumannomyces graminis </em>var.<em> tritici</em>), and the summer patch pathogen of turfgrass <em>Magnaporthiopsis poae </em>(syn. <em>Magnaporthe poae</em>). From our recent survey of fungi associated with grass roots, we discovered several new lineages in Magnaporthales. Based on multi-gene phylogenetic analysis and morphological and biological characteristics, three new genera (<em>Magnaporthiopsis</em>, <em>Pseudophialophora</em> and <em>Falciphora</em>), ten new species, and five new combinations have been proposed and published. Plant-fungal interaction experiments showed that <em>Pseudophialophora angusta</em>, <em>P. eragrostis</em>, <em>P. magnispora</em>, <em>P. schzachyrii</em>, <em>P. tarda</em>, and <em>P. whartonensis</em> that were isolated from grass roots in the New Jersey Pine Barrens had negative effects on the growth of switchgrass (<em>Panicum virgatum</em>). <em>Magnaporthiopsis meyeri-festucae</em> isolated from turfgrasses in New Jersey exhibiting summer patch-like symptoms was demonstrated to be pathogenic to hard fescue (<em>Festuca brevipila</em>) and Kentucky bluegrass (<em>Poa pratensis</em>). Furthermore, our phylogenomic analysis on the Magnaporthales fungi has provided insight into the evolution of pathogenicity and supported our taxonomic treatment of these taxa. This work will serve as the basis for future studies on biogeography, host range, biodiversity, evolution, and the impact of these plant pathogens on grass communities.</div>