Phylogeny of cercosporoid fungi (Mycosphaerellaceae, Mycosphaerellales) from Hawaii and New York reveals novel species within the Cercospora beticola complex

Abstract

The taxonomy of 44 specimens of cercosporoid fungi from Hawaii and New York, USA, was elucidated through multi-locus phylogenetic analyses of the LSU and ITS regions of the nrDNA as well as partial sequences of the actin, calmodulin, histone H3, and translation elongation factor 1-α genes. Sequences of four additional loci, namely, partial beta-tubulin, glyceraldehyde-3-phosphate dehydrogenase, the second largest subunit of RNA polymerase II, and the cercosporin facilitator protein-encoding gene, were used to resolve evolutionary species boundaries within the Cercospora beticola species complex using concatenated multi-locus phylogenies and the genealogical divergence index (gdi). Four novel Cercospora species, C. americana sp. nov., C. hawaiiensis sp. nov., C. manoa sp. nov., and C. tecta sp. nov. are described. Neocercospora carotae comb. nov. is made for Cercospora apii var. carotae, which is neotypified. Cercospora cf. citrulina and Pseudocercospora ocimi-basilici are reported for the first time in Hawaii. Cercospora beticola, Pluripassalora bougainvilleae, and Pseudocercospora pittospori are confirmed in Hawaii. Strelitziana africana, isolated from leaves of Ipomoea pes-caprae and Bougainvillea sp. affected by Cercospora spp., is reported for the first time in the USA.