Epicoccum nigrum Link, Mag. Ges. Naturf. Freunde Berlin

Lei, Yiming, Yang, Erfu, Dao, Chengjiao, Li, Xi, Karunarathna, Samantha C., Tibpromma, Saowaluck & Yan, Kai, 2023, Endophytic fungi associated with Coriaria nepalensis in an abandoned open-pit phosphate mine in Yunnan, P. R. China, Phytotaxa 616 (1), pp. 27-46 : 40

Epicoccum nigrum Link, Mag. Ges. Naturf. Freunde Berlin 7: 32 (1816) ( Figure 8 )

Index Fungorum number: IF226758

Endophytic on fresh leaves of Coriaria nepalensis Sexual morph: Unknown. Asexual morph on PDA: Mycelium composed of 2–7 µm (x = 5 µm; n = 15) wide, branched, hyaline, smooth and thick-walled hyphae, constricted at the septum. Conidiophores micronematous, inconspicuous. Conidiogenous cells 3–6.5 × 3–6 μm (x = 5.5 × 4.5 µm; n = 20), phialidic, hyaline, rounded ends, thin-walled. Conidia 16–21 × 15–20 μm (x = 18.5 × 18 µm; n = 20), brown to dark brown, mostly ellipsoid, rarely globose to subglobose, septate, apparently constricted at the septum, verrucose and sometimes with a basal cell.

Culture characteristics: Colonies on PDA, reaching around 20 mm diameter after 2 weeks at 20–25 ℃. Obverse: cream and yellowish mycelia, raised, lowly dense, effuse, irregular, fluffy. Reverse: sunk, dark brown at the centre, light brown at the margin. With golden brown pigments produced in PDA.

Distribution: Russia ( Hyde et al. 2018); China (This study).

Substratum: Acer negundo (Sapindaceae) ( Hyde et al. 2018); Coriaria nepalensis (This study).

Material examined: China, Yunnan Province, Kunming, Kunyang, an abandoned and Open-Pit Phosphate Mine , on fresh leaves of Coriaria nepalensis , 22August 2022, C. J. Dao, 2 MS1 L2 ( HKAS 129062 ), living culture KUNCC23- 13352 . GenBank number: ITS: OR094462 , LSU: OR094457 , rpb2: OR095636, tub2: OR095641 .

Notes: Our isolate shares similar conidia with the Epicoccum nigrum forming brown to dark brown, ellipsoid, globose to subglobose, septate, verrucose conidia ( Hyde et al. 2018). Based on the BLASTn search results of multi genes ( LSU, ITS, rpb2 and tub2), our isolate ( KUNCC 23-13352) show 99–100% similarity to E. nigrum strains ( CBS 231.59, CBS 125.82, CPO 10.815, LC 5180, MFLUCC 17-1171). In addition, the multi gene phylogenetic trees ( ML and BI) indicate our isolate clusters with the E. nigrum strains ( Figure 7 ). Therefore, we introduce our isolate as a new host record of E. nigrum based on BLASTn search results, morphological study and phylogenetic analyses.

Figures

FIGURE 7. Phylogram generated from Maximum Likelihood analysis based on a combined LSU, ITS, rpb2 and tub2 sequence datasets. The 71 strains are included in the combined gene analysis 2414 total character including gaps (LSU: 1–970 bp, ITS: 971–1476 bp, rpb2: 1477–2076 bp, tub2: 2077–2414 bp). Tree topology of the ML analysis was similar to the BI. The matrix had distinct alignment patterns, with the final ML optimization likelihood value of -10985.830126 (ln).All free model parameters were estimated by RAxML model, with 591 distinct alignment patterns and 9.91% of undetermined characters or gaps. Estimated base frequencies were as follows:A = 0.239938, C = 0.243524, G = 0.275052, T = 0.241487, with substitution rates AC = 1.455735, AG = 5.319539, AT = 1.539293, CG = 1.013949, CT = 11.131040, GT = 1.000000. The gamma distribution shape parameter alpha = 0.665812 and the Tree-Length = 0.755110. The final average standard deviation of split frequencies at the end of total MCMC generations was calculated as 0.009112 in BI analysis. The species introduced in this study are indicated in red, and the type strains are indicated in bold. Bootstrap values greater than 60% (ML, Left) and Bayesian posterior probabilities (BI, right) greater than 0.95 are given at the nodes. Hypens (-) represent values less than 60% in ML/0.95 in BI.

FIGURE 8. Epicoccum nigrum (HKAS 129062). (a,b) Obverse and reverse of colony on PDA; (a–b) Close up of the fruiting bodies on PDA; (e,f) Conidiogenous cells bearing conidia; (g) Mycelium; (h–m) Conidia.