Phylogenomic analysis of a 55.1 kb 19-gene dataset resolves a monophyletic Fusarium that includes the Fusarium solani Species Complex

Scientific communication is facilitated by a data-driven, scientifically sound taxonomy that considers the end-user¿s needs and established successful practice. In 2013, the Fusarium community voiced near unanimous support for a concept of Fusarium that represented a clade comprising all agriculturally and clinically important Fusarium species, including the F. solani species complex (FSSC). Subsequently, this concept was challenged in 2015 by one research group who proposed dividing the genus Fusarium into seven genera, including the FSSC described as members of the genus Neocosmospora, with subsequent justification in 2018 based on claims that the 2013 concept of Fusarium is polyphyletic. Here, we test this claim and provide a phylogeny based on exonic nucleotide sequences of 19 orthologous protein-coding genes that strongly support the monophyly of Fusarium including the FSSC. We reassert the practical and scientific argument in support of a genus Fusarium that includes the FSSC and several other basal lineages, consistent with the longstanding use of this name among plant pathologists, medical mycologists, quarantine officials, regulatory agencies, students, and researchers with a stake in its taxonomy. In recognition of this monophyly, 40 species described as genus Neocosmospora were recombined in genus Fusarium, and nine others were renamed Fusarium. Here the global Fusarium community voices strong support for the inclusion of the FSSC in Fusarium, as it remains the best scientific, nomenclatural, and practical taxonomic option availabl

Molecular characterization of Xanthomonas strains responsible for bacterial spot of tomato in Ethiopia

Bacterial spot of tomato (BST) is a major constraint to tomato production in Ethiopia and many other countries leading to significant crop losses. In the present study, using pathogenicity tests, sensitivity to copper and streptomycin, and multilocus sequence analysis (MLSA), we identified a diverse group of Xanthomonas strains isolated from central Ethiopia. None of the strains were sensitive to copper or streptomycin. Multilocus sequence analysis was used to compare Ethiopian strains with representative Xanthomonas strains from a worldwide collection based on DNA sequences of six housekeeping genes (lacF, lepA, gyrB, fusA, gltA and gapA) and hrpB genes.Phylogenetic analysis of the concatenated sequences showed that X. gardneri, X. vesicatoria andX. perforans were associated with BST in Ethiopia, whereas Xanthomonas euvesicatoria was absent from the Ethiopian sample. There was no genetic diversity among the isolated strains belonging to X. gardneri and X. perforans. However, two X. vesicatoria haplotypes were identified indicating at least two different sources of introduction of X. vesicatoria to Ethiopia. All of the X. perforans strains were only pathogenic on tomato and were T3 strains with the exception of one identified as tomato race 4 (T4). The X. gardneri and X. vesicatoria strains were tomato race 2 (T2), but were variable in pepper race determinations indicating variation in effectors among strains