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

Genetic diversity in the endangered Phebalium daviesii (Rutaceae) compared to that in two widespread congeners

Genetic diversity in the rare and endangered Phebalium daviesii was compared to that in P. squamulosum subsp. squamulosum and P. glandulosum subsp. glandulosum using allozyme analysis. Phebalium daviesii was once presumed extinct, but 43 adult plants have so far been rediscovered. Phebalium squamulosum subsp. squamulosum and P. glandulosum subsp. glandulosum are widespread in the south-eastern part of the Australian mainland. Morphologically, these two taxa are the closest relatives of P. daviesii and share a similarity with P. daviesii in their ecological habitat. The level of genetic diversity and deviations from Hardy-Weinberg equiibrium were investigated using allozyme data with 18 enzyme systems. Nei's total genetic diversity, the proportion of polymorphic loci and the average number of alleles per locus were all slightly lower in P. daviesii than in P. squamulosum subsp. squamulosum and P. glandulosum subsp. glandulosum. Deviations from expected Hardy-Weinberg equilibrium were present in all three taxa and were more frequent in P. glandulosum subsp. glandulosum. This suggests that inbreeding may be occurring in all three Phebalium taxa and that P. daviesii does not suffer from increased inbreeding due to rarity. Phebalium daviesii has a high level of genetic diversity (Ht = 0.30) for such a rare species and should be able to recover from its population bottleneck with appropriate management

Genetic evidence that Lomatia tasmanica (Proteaceae) is an ancient clone

Lomatia tasmanica W.M.Curtis is an endangered species with only one population. The population occurs over a distance of 1.2 km and consists of several hundred stems. Although it flowers occasionally, fruit production has never been observed, and it propagates vegetatively. The genetic diversity in L. tasmanica, and its relationship with the other species of this genus in Tasmania was investigated using allozyme analysis and chromosome counts. Sixteen isozyme loci were scored on 78 L. tasmanica plants collected from throughout the range of the species. No genetic diversity was found in L. tasmanica. Lomatia tinctoria possessed 22 (2n = 22) chromosomes, like other Lomatia species previously counted, while L. tasmanica had 33 to 29 chromosomes, which makes it an unstable triploid. The triploid nature of L. tasmanica would explain its lack of genetic diversity and its apparent sterility. This suggests that the entire species may be one genet, one of the largest plant clone ever found. Fossilised leaves identified as L. tasmanica by Jordan et al. (1991) and dated as at least 43 600 years old may indicate the minimum age of this genet. This clone maybe one the world’s oldest known living plant individual.