Systematics of Hypocrea citrina and related taxa

Abstract

Morphological studies and phylogenetic analyses of DNA sequences from three genomic regions – the internal transcribed spacer (ITS) regions of the nuclear ribosomal gene repeat, a partial sequence of RNA polymerase II subunit (rpb2), and a partial sequence of translation elongation factor (tef1) – were used to investigate the systematics of Hypocrea citrina and related species. A neotype specimen is designated for H. citrina that conforms to Persoon's description of a yellow effuse fungus occurring on leaf litter. Historical information and results obtained in this study provide the foundation for selection of a lectotype specimen from Fries's herbarium for H. lactea. The results indicate that (1) Hypocrea citrina and H. pulvinata are distinct species; (2) H. lactea sensu Fries is a synonym of the older name H. citrina; (3) H. pulvinata, H. protopulvinata, and H. americana are phylogenetically distinct species that form a well-supported polyporicolous clade; (4) H. citrina is situated in a clade closely related to H. pulvinata; and (5) H. microcitrina and H. pseudostraminea reside in a highly supported clade phylogenetically distinct from H. citrina. Hypocrea protopulvinata, H. microcitrina, H. megalocitrina, H. pseudostraminea, and a new species, H. aurantiistroma, are reported and described from North America. Variation in rpb2 and tef1 gene sequences suggests geographical subgroupings between European and North American isolates of H. pulvinata. The phylogenies inferred from ITS, rpb2, and tef1 gene sequences are concordant. Hypocrea citrina var. americana is elevated to species status, Hypocrea americana.

Re-evaluation of Hypocrea pseudogelatinosa and H. pseudostraminea isolated from shiitake mushroom (Lentinula edodes) cultivation in Korea and Japan

“…However, the length of phialides and conidia of this species are slightly different from those of H. pseudostraminea sensu Overton et al (2006a) and H. decipiens in anamorphic characteristics (Table 3). In addition, they could be distinguished by their ITS, tef1 and rpb2 sequences.…”

“…Colonies on PDA at 25 *data from Chaverri & Samuels (2003) M. Komatsu (specimen: TMI 8495; culture: TMIC 61407= TUFC 61407), Tottori, 1965 (culture: TMIC 60104=TUFC 60104) Notes: Hypocrea pseudostraminea/Trichoderma pseudostramineum is almost indistinguishable from H. pseudostraminea sensu Overton et al (2006a) and H. decipiens in teleomorphic characteristics. However, the length of phialides and conidia of this species are slightly different from those of H. pseudostraminea sensu Overton et al (2006a) and H. decipiens in anamorphic characteristics (Table 3).…”

“…Hypocrea pseudostraminea was originally described from Japan by Doi (1972). Recently Overton et al (2006a) re-described the species based on teleomorph morphology and phylogenetic analyses, but they did not sequence DNA from any Japanese strains. Jaklitsch (2011) suggested that H. pseudostraminea sensu Overton et al (2006a) was misidentified based on Jaklitsch's re-examination of European specimens, including specimens used by Overton et al (2006a).…”

“…Recently Overton et al (2006a) re-described the species based on teleomorph morphology and phylogenetic analyses, but they did not sequence DNA from any Japanese strains. Jaklitsch (2011) suggested that H. pseudostraminea sensu Overton et al (2006a) was misidentified based on Jaklitsch's re-examination of European specimens, including specimens used by Overton et al (2006a). According to Jaklitsch (2011), European specimens of H. pseudostraminea sensu Overton et al (2006a) produced green conidia, but in the original description of H. pseudostraminea, it produced hyaline conidia.…”

“…Our specimens showed nearly identical morphological characters to H. pseudostraminea sensu Overton et al (2006a). Because morphology alone was insufficient to identify this fungus, we also conducted detailed phylogenetic analyses.…”