Nigrograna puerensis L. Lu & Tibpromma, 2022

Lu, Li, Karunarathna, Samantha C., Dai, Dong-qin, Jayawardena, Ruvishika S., Suwannarach, Nakarin & Tibpromma, Saowaluck, 2022, Three new species of Nigrograna (Dothideomycetes, Pleosporales) associated with Arabica coffee from Yunnan Province, China, MycoKeys 94, pp. 51-71 : 51

Nigrograna puerensis L. Lu & Tibpromma sp. nov.

Fig. 3

Etymology.

The specific epithet " Nigrograna puerensis " refers to the location Pu’er City, where the type species was collected.

Holotype.

ZHKU 22-0122.

Description.

Saprobic on decaying branch of Coffea arabica . Sexual morph: Ascomata 90-180 µm high, 90-150 μm wide (x̄ = 138 × 115 μm, n = 10), immersed, with only ostiolar necks visible on the host surface or erumpent, solitary, subglobose to ellipsoid, dark brown (#6e5031). Peridium 10-15 μm wide (x̄ = 13 μm, n = 15), outer layer consists of 2-3 layers of textura prismatica, brown (#937463) and thick-walled cells, inner layer hyaline with thin-walled cells. Hamathecium composed of numerous, 1.5-2 µm wide (x̄ = 1.8 μm, n = 20), filamentous, hyaline, septate, pseudoparaphyse. Asci 50-80 × 8-11 μm (x̄ = 66 × 9.5 μm, n = 20), 8-spored, bitunicate, fissitunicate, cylindrical to clavate, short pedicellate, apically rounded, with poorly developed ocular chamber. Ascospores 15-18 × 4-5 μm, (x̄ = 16 × 4.5 μm, n = 30), uni- to bi-seriately arranged, fusoid, apical cell and basal cell acute, and apical cell slightly wider than basal cell, straight or slightly curved, 1-septate, constricted at septum, guttulate, hyaline to yellow-brownish (#daceb8) when young, brownish (#937463) when mature. Asexual morph: Undetermined.

Culture characteristics.

On PDA, colonies reached up to 4 cm diam. after two months at room temperature (22-26 °C). Colony dense, circular, slightly raised at the center, surface with white aerial mycelium, fluffy, with a serrate edge, grayish (#c9bfb3) to dark brown (#6e5031) from center to edge, reverse dark green (#3a4543) to dark brown (#6e5031).

Material examined.

Pu'er City , Yunnan Province, China, on a decaying branch of Coffea arabica , (22°36'2"N, 101°0'59"E, 1016.43 m), 16 September 2021, LiLu, Puer 1-4 (ZHKU 22-0122, holotype), ZHKUCC 22-0212 = ZHKUCC 22-0213. GenBank number; ITS: OP450969 , LSU: OP450975 , SSU: OP450983 , tef 1-α: OP432249 (ZHKUCC 22-0212, ex-type); ITS: OP450970 , LSU: OP450976 , SSU: OP450984 , tef 1-α: OP432250 (ZHKUCC 22-0213) .

Notes.

Nigrograna puerensis clusters with N. carollii with significant statistical support from ML 100% and BIPP 1.00. In morphology, our new strains best fit Nigrograna by having immersed ascomata, clavate and short pedicellate asci, and pale to brown, fusoid to narrowly ellipsoid, and septate ascospores ( Jaklitsch and Voglmayr 2016; Zhang et al. 2020). Blast search results of ITS, LSU and tef 1-α sequence data revealed that our taxon (ZHKUCC 22-0212) is similar to N. mackinnonii (96% MZ270697, 99% KJ605422, and 95% LT797087 respectively), while the similarity of SSU sequence to N. carollii is as high as 99%. Based on nucleotide comparisons, our isolate (ZHKUCC 22-0212) differs from N. carollii (CCF 4484) by 9/490 bp (1.8%) in ITS, 2/222 bp (1%) in LSU, 2/1306 bp (0.2%) in SSU, and 10/530 bp (2%) in tef 1-α. Unfortunately, for N. carollii , sufficient morphological data was not available to compare with our novel taxon which was isolated as an endophyte on living sapwood of wild Hevea brasiliensis Müll. Arg., and N. mackinnonii which was isolated as a human pathogen ( de Gruyter 2012; Kolařík et al. 2017). In addition, the colony morphology of N. carollii on PDA is described as colonies plane, effuse, and light gray ( Kolařík et al. 2017), while N. puerensis colony surface is seen as white aerial mycelium, fluffy, with a serrate edge, and grayish to dark brown from center to edge. Therefore, based on morphological and phylogenetic analyses, we introduce N. puerensis as a distinct new species.

Figures

Figure 3. Nigrograna puerensis (ZHKU 22 - 0122, holotype) a, b ascomata observed on host substrate c a vertical section through an ascoma d peridium e hamathecium f-j asci k germinated ascospore l-p ascospores q culture on PDA from above and reverse. Scale bars: 50 μm (c); 30 μm (d); 15 μm (e-k); 5 μm (l-p).