Pleosporales » Nigrogranaceae » Nigrograna

Nigrograna lincangensis

Nigrograna lincangensis R.F. Xu & Tibpromma, in Xu, Karunarathna, Phukhamsakda, Dai, Elgorban, Suwannarach, Kumla, Wang & Tibpromma, Index Fungorum 103: 78 (2024)

Index Fungorum number: IF 901420

Saprobic on a dead branch of Hevea brasiliensis. Sexual morph: Ascomata 285–360 μm high, 230–307 μm diam. (= 337 × 272 μm, n = 5), immersed, under the clypeus, sometimes inconspicuous on host surface and small bumps can be seen, solitary, dark brown, globose or ellipsoid, with papilla. Ostioles 117–217 × 68–124 μm ( = 152 × 99 μm, n = 10), central, brown, papillate. Peridium 16–45 μm wide, comprising several layers with dark-brown to dark cells of textura angularis. Hamathecium comprises 1.5–3 μm wide, unbranched, septate, hyaline, pseudoparaphyses. Asci 45–70 × 9–12 μm ( = 57 × 10 μm, n = 10), 8-spored, bitunicate, pedicellate, club shape, cylindrical to clavate, straight or slightly curved, apically rounded, thick-walled. Ascospores 10–15 × 4–6 μm ( = 13 × 4.8 μm, n = 30), 1–2-seriate, initially 1-septate, becoming 3-septate at the maturity, fusoid to narrowly ellipsoid, upper part or second cell slightly wider and tapering towards narrow ends, constricted at the septa, hyaline to yellow-brown to brown with age, guttulate, think-walled. Asexual morph: Undetermined.

            Culture characteristics: Spores germinated within 12 hours, colonies grow on PDA at 28 °C, circular, floppy, entire edge, raised, grey to taupe, reverse dark brown.

            Material examined: China, Yunnan Province, Lincang, on a dead branch of Hevea brasiliensis, 28 July 2022, Rui-Fang Xu, LCR06, (ZHKU 23–0104, holotype); ex-type ZHKUCC 23–0798, ZHKUCC 23–0799.

            GenBank numbers: ZHKUCC 23–0798 = ITS: OR853099, LSU: OR922323, SSU: OR941079, tef1-α: OR966282, rpb2: OR966280; ZHKUCC 23–0799 = ITS: OR853100, LSU: OR922324, SSU: OR941080, tef1-α: OR966283, rpb2: OR966281.

     Notes: Nigrograna lincangensis has similar ascomata, asci and ascospore characteristics similar to other Nigrograna species (Jaklitsch and Voglmayr 2016; Hyde et al. 2017; Tibpromma et al. 2017; Dayarathne et al. 2020; Mapook et al. 2020; Lu et al. 2022). However, N. lincangensis differs from N. cangshanensis by having larger ascomata (285–360 × 230–307 μm vs. 120–135 × 135–155 μm) (Tibpromma et al. 2017). Nigrograna chromolaenae can be distinguished from N. lincangensis in having smaller ascomata (160–280 × 115–130 μm vs. 285–360 × 230–307 μm), smaller asci (40–55 × 7–10 μm vs. 45–70 × 9–12 μm), and greyish-brown to dark brown ascospores (Mapook et al. 2020). Nigrograna coffeae differs from N. cangshanensis by having smaller ascomata (90–140 × 140–200 μm vs. 285–360 × 230–307 μm), 1-septate ascospores (Lu et al. 2022). Nigrograna novergica differs from N. lincangensis as it occurs on pseudostromata from the host of Diaporthe sp. (Jaklitsch and Voglmayr 2016). Nigrograna mycophila and N. obliqua are distinct from N. lincangensis by having dark brown ascospores (Jaklitsch and Voglmayr 2016). Nigrograna puerensis differs from N. lincangensis by having acute apical and basal cells and the apical cells are wider than the basal cells (Lu et al. 2022). Nigrograna samueliana differs from N. lincangensis by the absence of ostiole (Dayarathne et al. 2020). Nigrograna thymi can be easily distinguished from N. lincangensis in having 4–5 septate (Hyde et al. 2017). Therefore, N. lincangensis is described here as a new species, based on phylogeny and morphology. 

 

Figure 1. Phylogram generated from Maximum Likelihood analysis based on combined LSU, ITS, SSU, tef1-α and rpb2 sequence data of 119 taxa, which comprised 4399 base pairs (LSU = 908 bp, ITS = 512 bp, SSU = 1000 bp, tef1-α = 925 bp, rpb2 = 1054 bp). The best scoring RAxML tree with a final likelihood value of -38918.764563 is presented. The matrix had 2023 distinct alignment patterns, with 39.00% of undetermined characters or gaps. Estimated base frequencies were as follows: A = 0.245191, C = 0.247520, G = 0.268228, T = 0.239061; substitution rates: AC = 1.533778, AG = 3.877174, AT = 1.672983, CG = 1.254032, CT = 8.838860, GT = 1.000000; gamma distribution shape parameter α = 0.208600. Bootstrap support values for ML equal to or greater than 60% and Bayesian Inference analysis values equal to or greater than 0.90 PP are labelled at each node. The tree is rooted with Seriascoma didymospora (MFLUCC 11–0179) and S. didymospora (MFLUCC 11–0194).

 

Figure 2. Nigrograna lincangensis (ZHKU 23–0104, holotype) a–c appearance of ascomata on the host surface d vertical section of an ascoma e vertical section of ostiole f hamathecium and asci g section of peridium h–k asci l ascospores m a germinated ascospore n, o colonies on PDA (n-front and o-reverse views). Scale bars: 100 µm (d); 50 µm (e); 30 µm (f); 200 µm (g); 10 µm (h–k); 5 µm (l); 20 µm (m).

 

References

1. Xu R-F, karunaratha SC, Phukhamsakda C, Dai D-Q, et al. (2024) Four new species of Dothideomycetes (Ascomycota) from Pará Rubber (Hevea brasiliensis) in Yunnan Province, China. MycoKeys 103, 71–95.

 

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