Dictyoarthrinium endophyticum R.M.F. Silva, T.G.L. Oliveira & G.A. Silva, sp. nov.

Index Fungorum number: IF 900386; Mycobank number: MB 900386; Facesoffungi number: FoF 14102 Fig. 1

Etymology – In reference to the endophytic lifestyle in eggplant

Holotype – URM 95262.

Endophyte from leaves of Solanum melongena. Sexual morph: Not observed. Asexual morph: Mycelium composed of septate, anastomosing, branched, 3–4 μm in width, pale brown hyphae. Conidiophores 61–111 × 3–5 μm, (x̅=71 × 3.4 μm, n=15) macronematous, basauxic, cylindrical, narrow, straight or flexuous, pale brown, rough and thin-walled terminating in conidiophore mother cells, the transverse septa dark brown with distances of 3.6–8.7 μm, rough-walled. Conidiogenous cells 5–7×3.5–5 μm (x̅=5.8×4.1 μm, n=10), blastic, integrated, intercalary and terminal, cylindrical, hyaline, Conidia 5.4–12.5 × 6.4–12 μm., (x̅=8.3 × 8.5 μm, n=30) arising from the lateral or apical part of conidiophores, hyaline, subhyaline to pale brown when young and brown to dark brown when mature, verrucose, spherical or subspherical, septate with 4-cells.

Culture characteristics – Colonies after 7 days on PDA growing up to 6 mm diam at 25 °C with surface yellow buff and reverse brownish yellow with white margins.

Material examined – Brazil, Pernambuco State, Chã Grande municipality, isolated as endophyte from leaves of Solanum melongena (Solanaceae), 18 July 2021, R.M.F. Silva (URM 95262, holotype); ex-type URM 8697.

GenBank numbers – ITS: OQ534286; LSU: OQ534288; tef1-α: OQ544569.

Notes – Dictyoarthrinium endophyticum is introduced as a new species based on its distinct morphology and the phylogeny of the combined LSU, ITS, and tef1-α dataset. The phylogenetic tree showed that the sequences obtained from Dictyoarthrinium endophyticum clustered, forming a single well-supported clade, in the genus Dictyoarthrinium close to D. hydei and D. sacchari (Fig. 2). However, D. hydei, described as saprobic on decaying wood submerged in freshwater, produces larger conidia (9–17 × 8–13 μm) and conidiophores (400 × 3–5.5 μm) (Maharachchikumbura et al. 2021), while D. endophyticum produces conidia (5.4–12.5×6.4–12 μm) and conidiophores ((30)61–111×3–5 μm). Dictyoarthrinium sacchari, found as saprobic on dead leaves of Musa sp., different from D. endophyticum produces acropleurogenic conidia, sometimes square with 2 or 4 cells (Samarakoon et al. 2020a, b). Many Dictyoarthrinium species are saprobes that colonize dead plants (Somrithipol 2007; Leão-Ferreira and Gusmão 2010; Tarda et al. 2019). In the present study, D. endophyticum was described from the healthy leaves of S. melongena.

Figure 1 – Dictyoarthrinium endophyticum (URM 95262, holotype). a Colony on PDA after 7 d at 25 °C. b, c Conidiophores. d Conidia. e Beginning of conidial germination. f–g Conidia. Scalebars:=10 µm

Figure 2 – Phylogenetic tree generated from Bayesian inference (BI) analysis based on combined LSU rDNA, ITS and tef1-α sequences. The matrix contained 2346 characters (LSU rDNA=841, ITS=599, and tef1-α=906), inclusive of gaps. The optimal nucleotide substitution model for the BI analysis was GTR+G for LSU rDNA and tef1-α, and HKY+G for ITS. GTR+G+I was used as the ideal model for maximum likelihood analysis. Sequences from type species are indicated in bold. The new species is indicated in blue. Bayesian posterior probabilities (above 0.92) and maximum likelihood bootstrap (above 70%) values are shown near nodes. The tree is rooted with Spegazzinia radermacherae MFLUCC 17–2285 and Spegazzinia tessarthra SH 287