Abstract
Digitodesmium is a genus of saprobic fungi, generally associated with decaying wood in freshwater habitats or in the soil. Fungi in this genus produce cheiroid, euseptate conidia on sporodochia. During an exam of a necrotic robusta coffee stem sent from Nova Venécia, state of Espírito Santo, to the Plant Clinic at the Universidade Federal de Viçosa (Brazil), for disease diagnosis, a fungus, recognized as having the typical features of Digitodesmium, was observed. The fungus was isolated in pure culture and DNA was extracted. Sequences of the partial 18S ribosomal RNA gene, large subunit of the nrDNA, internal transcribed spacer, and translation elongation factor 1-α were generated. The combination of results of the phylogenetic analysis with the exam of the morphology led to the conclusion that the fungus from the dead coffee stems represents a monophyletic distinct lineage within Digitodesmium and an undescribed species for the genus. The concatenate tree also revealed that Digitodesmium is divided in two distinct clades. The novel species can be differentiated morphologically from other species of Digitodesmium by the size of the conidia, the number of arms, and the presence of appendages. The new species Digitodesmium polybrachiatum is hence proposed herein. A comparative table of conidial morphology for the species in the genus is also included.
Highlights
The combination of results of the phylogenetic analysis with the exam of the morphology led to the conclusion that the fungus from coffee stem morphological data showed that this fungus represents a monophyletic distinct lineage within Digitodesmium and an undescribed species for the genus
The family Dictyosporiaceae was introduced by Boonmee et al (2016) to accommodate a group of fungi belonging to the Dothideomycetes that are saprobes on decaying wood and plant debris in terrestrial and freshwater habitats typically having cheiroid, digitate, palmate and/or dictyosporous conidia
Six more species were described within this genus, namely: D. recurvum recorded from freshwater habitats in Hong Kong, China (Ho et al 1999); D. bambusicola on bamboo culms submerged in river from Philippines (Cai et al 2002); D. heptasporum found on wood submerged in forest stream, from Yunnan, China (Cai et al 2003); D. intermedium and D. macrosporum, obtained respectively from plant debris and from a soil sample, both collected in Spain (Silvera-Simón et al 2010); and D. chiangmaiense isolated from dead wood in Thailand (Hyde et al 2019)
Summary
The family Dictyosporiaceae was introduced by Boonmee et al (2016) to accommodate a group of fungi belonging to the Dothideomycetes that are saprobes on decaying wood and plant debris in terrestrial and freshwater habitats typically having cheiroid, digitate, palmate and/or dictyosporous conidia. Six more species were described within this genus, namely: D. recurvum recorded from freshwater habitats in Hong Kong, China (Ho et al 1999); D. bambusicola on bamboo culms submerged in river from Philippines (Cai et al 2002); D. heptasporum found on wood submerged in forest stream, from Yunnan, China (Cai et al 2003); D. intermedium and D. macrosporum, obtained respectively from plant debris and from a soil sample, both collected in Spain (Silvera-Simón et al 2010); and D. chiangmaiense isolated from dead wood in Thailand (Hyde et al 2019)
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