Nigrograna oleae W. L. Li & Jian K. Liu

Du, Hong-Zhi, Lu, Yu-Hang, Cheewangkoon, Ratchadawan & Liu, Jian-Kui, 2024, Morpho-phylogenetic evidence reveals novel species and new records of Nigrograna (Nigrogranaceae) associated with medicinal plants in Southwestern China, MycoKeys 110, pp. 1-33 : 1-33

Nigrograna oleae W. L. Li & Jian K. Liu , Mycosphere, 14 (1): 1503–1505 (2023)

Fig. 6

= Nigrograna trachycarpi , MycoKeys 100: 141 (2023).

Description.

Saprobic on dead branches of Ardisia crenata ( Primulaceae ). Sexual morph: Ascomata 190–334 μm wide, 303–406 μm high (x ̅ = 233 × 370 μm, n = 20), solitary or gregarious, scattered, immersed, often lying parallelly or obliquely to the bark or host surface, with a cylindrical ostiolar neck, coriaceous, obpyriform, brown to dark brown. Ostioles central or eccentric, filled with hyaline periphyses. Peridium 16.5–25 μm (x ̅ = 21 μm, n = 20) wide, consisting 4–6 layers of brown-walled cells of textura angularis. Hamathecium 1–2 μm (x ̅ = 1.5 μm, n = 20) wide, aseptate or separate, composed of numerous, filiform, smooth-walled pseudoparaphyses. Asci 62–127 × 9–12 μm (x ̅ = 82 × 10 μm, n = 30), 8 - spored, bitunicate, fissitunicate, clavate to long cylindric-clavate, with a short pedicel, apically rounded, with a smaller ocular chamber. Ascospores 14–17 × 4–6 μm (x ̅ = 15 × 5 μm, n = 50), 1–2 - seriate, fusoid to ellipsoid, apical cell mostly obtuse, straight or slightly curved, guttulate, smooth-walled, 3 - septate, constricted at the septa, pale brown to yellow-brown when young, brown to chocolate-brown at maturation, without appendages. Asexual morph: Undetermined.

Culture characteristics.

Ascospores germinated on PDA within 24 h, and germ tubes produced from basal cell. Colonies growing on PDA reached 22–23 mm in diameter after three weeks at 25 ° C in dark. Colonies from above, circular, margin entire, dense, surface smooth, velvety appearance, white in the center, presented a pale greenish furrowed ring, white to cream at the margin; in reverse, brown in the central point, brown-gray in the middle, white to pale brownish at the edge, no pigmentation on PDA.

Material examined.

China • Yunnan Province, Xishuangbanna Dai Autonomous Prefecture, Mengla County, Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences . 21°55'49′′N, 101°15'19′′E, elevation 516 m, on dead branches of medicinal plant Ardisia crenata Sims ( Primulaceae ), 10 November 2022, H. Z. Du, D 01 ( HUEST 23.0209 ), living culture UESTCC 23.0209 ; • ibid., Sichuan Province, Chengdu City , Pujiang County, 30°11'42"N, 103°22'21"E, elevation 630 m, on dead branches of Camellia sinensis (L.) O. Ktze . ( Theaceae ), 5 October 2022, Y. H. Lu & Y. Xiao, A 11 ( HUEST 23.0193 ), living culture UESTCC 23.0193 .

Notes.

Nigrograna oleae was introduced by Li et al. (2023) from Olea europaea and N. trachycarpi was described by Hu et al. (2023) from Trachycarpus sp. in China. In this study, multi-locus phylogeny indicated that our two isolates clustered together with N. oleae (ex-type strain, CGMCC 3.24423 ) and N. trachycarpi (ex-type strain, GMB 0499) by strong support (100 % MLBS / 1.00 BIPP) (Fig. 1 ). In addition, the nucleotide base pair comparison of ex-type strain between N. oleae ( CGMCC 3.24423 ) and N. trachycarpi ( GMB 0499) was identical by 421 / 421 bp (100 %) of ITS, and 466 / 466 bp (100 %) of tef 1 - α. Additionally, our newly collected specimens share similar morphology with N. oleae and N. trachycarpi . Therefore, we identify our collections as N. oleae and propose the synonymy of N. trachycarpi under N. oleae based on morphology and phylogeny. The new host records for N. oleae from medicinal plants Ardisia crenata and Camellia sinensis are reported in this study.

Figures

Figure 1. Phylogenetic tree constructed from maximum likelihood (RAxML) analyses of a combined ITS, LSU, rpb 2, SSU, and tef 1 - α sequence data for selected genera within the family Nigrogranaceae (Pleosporales, Dothideomycetes). Branches support for Maximum likelihood (MLBS) equal to or greater than 75 % and Bayesian inference posterior probabilities (BIPP) equal to or greater than 0.95 are marked above or below nodes as MLBS / BIPP. The abbreviation T indicates the ex-type strain. Species names and culture collections in red are newly collected taxa and synonymized isolates. The tree was rooted with Occultibambusa pustula (MFLUCC 11-0502) and O. bambusae (MFLUCC 13-0855).

Figure 6. Nigrograna oleae (HUEST 23.0209, new host record) a host Ardisia crenata b branch of Ardisia crenata c – f appearance of ascomata on host surface g, h vertical section through ascoma i peridium j – l asci m – q ascospores r, s colony on PDA, above (r) and below (s). Scale bars: 100 µm (g, h); 20 µm (i-l); 10 µm (m – q).