Multigene phylogeny and taxonomy of Dendryphion hydei and Torula hydei spp. nov. from herbaceous litter in northern Thailand

Abstract

During our studies on asexual fungi colonizing herbaceous litter in northern Thailand, we discovered two new fungal species, viz. Dendryphion hydei and Torula hydei spp. nov. The latter are examined, and their morphological characters are described as well as their DNA sequences from ribosomal and protein coding genes are analysed to infer their phylogenetic relationships with extant fungi. Torula hydei is different from other similar Torula species in having tiny and catenate conidia. Dendryphion hydei can be distinguished from other similar Dendryphion species in having large conidiophores and subhyaline to pale olivaceous brown, 2-4(-5)-septate conidia. Multigene phylogenetic analyses of a combined LSU, SSU, TEF1-α, RPB2 and ITS DNA sequence dataset generated from maximum likelihood and Bayesian inference analyses indicate that T. hydei forms a distinct lineage and basal to T. fici. Dendryphion hydei forms a distinct lineage and basal to D. europaeum, D. comosum, D. aquaticum and D. fluminicola within Torulaceae (Pleosporales, Dothideomycetes).

Fig 1. Phylogenetic construction using RAxML-based analysis of a combined LSU, SSU, TEF1-α, RPB2 and ITS DNA sequence dataset.

Bootstrap support values for maximum likelihood (ML) equal to or greater than 50% and Bayesian posterior probabilities (PP) equal to or greater than 0.95 are shown as “ML/PP” above the nodes. The tree is rooted to Occultibambusa bambusae (MFLUCC 13–0855) and Neooccultibambusa chiangraiensis (MFLUCC 12–0559). The type strains are in black bold and the newly generated sequences are indicated in blue bold.

Fig 2

Dendryphion hydei (HKAS 97479, holotype) a Colonies on branch of Bidens pilosa. b, c Apex of conidiophores with conidial structures. d, e Conidiophores. f–i Conidiogenous cells. j–q Conidia. Scale bars: a = 100 μm, d, e = 50 μm, b, f–i = 20 μm, b, c, f–q = 10 μm.

Fig 3. Torula hydei (HKAS 97478, holotype).

a Colonies on dead branch of Chromolaena odorata. b–e Conidiophores with conidiogenous cell. f–j Budding on conidia. k, l Conidia in chain. m–t Conidia. Scale bars: a = 100 μm, b, k–l = 5 μm, c, f–j, q–t = 2 μm, d, e, m–p = 1 μm.