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Cucurbitariaceae has a high biodiversity worldwide on various hosts and is distributed in tropical and temperate regions. Woody litters collected in Changchun, Jilin Province, China, revealed a distinct collection of fungi in the family Cucurbitariaceae based on morphological and molecular data. Phylogenetic analyses of the concatenated matrix of the internal transcribed spacer (ITS) region, the large subunit (LSU) of ribosomal DNA, the RNA polymerase II subunit (rpb2), the translation elongation factor 1-alpha (tef1-α) and β-tubulin (β-tub) genes indicated that the isolates represent Allocucurbitaria and Parafenestella species based on maximum likelihood (ML), maximum parsimony (MP) and Bayesian analysis (BPP). We report four novel species: Allocucurbitaria mori, Parafenestella changchunensis, P. ulmi and P. ulmicola. The importance of five DNA markers for species-level identification in Cucurbitariaceae was determined by Assemble Species by Automatic Partitioning (ASAP) analyses. The protein-coding gene β-tub is determined to be the best marker for species level identification in Cucurbitariaceae. [ABSTRACT FROM AUTHOR]

Amanita cf. lavendula collections in eastern North America, Mexico, and Costa Rica were found to consist of four cryptic taxa, one of which exhibited consistently unreadable nuclear rDNA ITS1-5.8S-ITS2 (fungal barcode) sequences after ITS1 base 130. This taxon is designated here as Amanita cf. lavendula taxon 1. ITS sequences from dikaryotic basidiomata were cloned, but sequences recovered from cloning did not segregate into distinct haplotypes. Rather, there was a mix of haplotypes that varied among themselves predominantly at 28 ITS positions. Analysis of each of these 28 variable bases showed predominantly two alternate bases at each position. Based on these findings and additional sequence data from the nuclear rDNA 28S, RNA polymerase II subunit 2 (RPB2) and mitochondrial rDNA small subunit (SSU) and 23S genes, we speculate that taxon 1 represents an initial hybridization event between two divergent taxa followed by failure of the ribosomal repeat to homogenize. Homogenization failure may be a result of repeated hybridization between divergent internal transcribed spacer (ITS) types with inadequate time for concerted evolution of the ribosomal repeat or, alternately, a complete failure of the ribosomal homogenization process. To our knowledge, this finding represents the first report of a geographically widespread taxon (Canada, eastern USA, Costa Rica) with apparent homogenization failure across all collections. Findings such as these have implications for fungal barcoding efforts and the application of fungal barcodes in identifying environmental sequences. [ABSTRACT FROM AUTHOR]