<i>Fusarium</i> diversity associated with diseased cereals in China, with an updated phylogenomic assessment of the genus

Abstract

<i>Fusarium</i> species are important cereal pathogens that cause severe production losses to major cereal crops such as maize, rice, and wheat. However, the causal agents of <i>Fusarium</i> diseases on cereals have not been well documented because of the difficulty in species identification and the debates surrounding generic and species concepts. In this study, we used a citizen science initiative to investigate diseased cereal crops (maize, rice, wheat) from 250 locations, covering the major cereal-growing regions in China. A total of 2 020 <i>Fusarium</i> strains were isolated from 315 diseased samples. Employing multi-locus phylogeny and morphological features, the above strains were identified to 43 species, including eight novel species that are described in this paper. A world checklist of cereal-associated <i>Fusarium</i> species is provided, with 39 and 52 new records updated for the world and China, respectively. Notably, 56 % of samples collected in this study were observed to have co-infections of more than one <i>Fusarium</i> species, and the detailed associations are discussed. Following Koch's postulates, 18 species were first confirmed as pathogens of maize stalk rot in this study. Furthermore, a high-confidence species tree was constructed in this study based on 1 001 homologous loci of 228 assembled genomes (40 genomes were sequenced and provided in this study), which supported the "narrow" generic concept of <i>Fusarium</i> (= <i>Gibberella</i>). This study represents one of the most comprehensive surveys of cereal <i>Fusarium</i> diseases to date. It significantly improves our understanding of the global diversity and distribution of cereal-associated <i>Fusarium</i> species, as well as largely clarifies the phylogenetic relationships within the genus. <b>Taxonomic novelties:</b> <b>New species:</b> <i>Fusarium erosum</i> S.L. Han, M.M. Wang & L. Cai, <i>Fusarium fecundum</i> S.L. Han, M.M. Wang & L. Cai, <i>Fusarium jinanense</i> S.L. Han, M.M. Wang & L. Cai, <i>Fusarium mianyangense</i> S.L. Han, M.M. Wang & L. Cai, <i>Fusarium nothincarnatum</i> S.L. Han, M.M. Wang & L. Cai, <i>Fusarium planum</i> S.L. Han, M.M. Wang & L. Cai, <i>Fusarium sanyaense</i> S.L. Han, M.M. Wang & L. Cai, <i>Fusarium weifangense</i> S.L. Han, M.M. Wang & L. Cai. <b>Citation:</b> Han SL, Wang MM, Ma ZY, Raza M, Zhao P, Liang JM, Gao M, Li YJ, Wang JW, Hu DM, Cai L (2023). <i>Fusarium</i> diversity associated with diseased cereals in China, with an updated phylogenomic assessment of the genus. <i>Studies in Mycology</i> <b>104</b>: 87-148. doi: 10.3114/sim.2022.104.02.