Atrokylindriopsis racemosospora Senwanna, J. Kumla & N. Suwannar., 2025

Senwanna, Chanokned, Kumla, Jaturong, Kodchasee, Pratthana, Duangkon, Nutchanan & Suwannarach, Nakarin, 2025, Additions of New Endolichenic Fungi to Herpotrichiellaceae (Chaetothyriales, Ascomycota) from northern Thailand, MycoKeys 120, pp. 193-229 : 193-229

Atrokylindriopsis racemosospora Senwanna, J. Kumla & N. Suwannar. sp. nov.

Fig. 2

Etymology.

In reference to the spore arrangement resembling a raceme form.

Type.

Thailand • Chiang Mai Province: Chai Prakan District, Nong Bua Subdistrict , endolichenic from the medulla of foliose lichen ( Parmotrema sp. ) on Prunus domestica , 19°42'23"N, 99°1'32"E, elevation 1160 m, 2 June 2023, C. Senwanna and N. Suwannarach, CMUB 40067 (Holotype, preserved in a metabolically inactive state. Ex-type living culture LC 05-1 = SDBR-CMU 502 ) .

Cultural characteristics.

Colonies on different agar media were incubated in the dark at 25 ° C for 2 months; colonies flat, irregular, with edge undulate, velvety; on PDA (18 to 27 mm in diameter) surface grayish brown, light brown at the margin, reverse olivaceous black, light brown at the margin; on MEA (18 to 23 mm in diameter) surface grayish brown, dark brown to black at the margin, reverse olivaceous black, producing brown pigment in agar; on OA (17 to 23 mm in diameter) surface grayish brown, reverse olivaceous black, sporulation absent; on PCA (17 to 20 mm in diameter) surface and reverse brownish gray, reverse olivaceous black, sporulation absent. On CMD (15 to 20 mm in diameter) surface and reverse grayish brown; and on CMA (20 to 27 mm in diameter) surface and reverse brownish grey, sporulation absent. Asexual morph in vitro dematiaceous hyphomycetes. Hyphae 1–2.5 µm wide, pale brown, simple to branched, septate, smooth, thin-walled, coiling, anastomosis observed. Conidiophores (10 –) 20–111 (– 153) × (1.4 –) 1.8–2.6 (– 2.9) µm (x ̄ = 53.17 × 2.15, n = 40), macronematous, monomematous, straight or slightly flexuous, unbranched, continuous or 1–3 septate, dark brown, paler terminally, smooth-, thick-walled. Conidiogenous cells (6.6 –) 15.5–36 (– 45.5) × (1.4 –) 1.8–2.6 (– 2.9) µm (x ̄ = 25.5 × 2.16, n = 40), integrated, polyblastic, terminal to mostly intercalary, proliferating sympodial and producing conidia from short denticles, subcylindrical, pale brown to brown, fertile parts subhyaline; denticles scattered, slightly darkened, 0.4–1 µm wide. Conidia (2.5 –) 2.8–4.4 (– 5) × (1.8 –) 2–3.3 µm (x ̄ = 3.72 × 2.68, n = 40), abundant, obovoid or subglobose, with a round apex, and slightly truncate base, aseptate, subhyaline to pale brown, smooth-walled, with inconspicuous conidial scars, 0.5–1 µm wide. Chlamydospores rare, solitary or in chains, terminal, globose to pyriform, without or one-septate, pigmented, dark brown, smooth-, thick- walled. Sexual morph unknown.

Cardinal temperatures for growth on MEA after two weeks

(mm). Optimum at the range of 25 ° C to 30 ° C (10 to 14). No growth 4 ° C and 35 ° C.

Additional materials examined.

Thailand • Chiang Mai Province, Chai Prakan District, Nong Bua Subdistrict , endolichenic from the medulla of foliose lichen ( Parmotrema sp. ) on Prunus domestica , 19°42'23"N, 99°1'32"E, elevation 1160 m, 2 June 2023, C. Senwanna and N. Suwannarach, living culture (LC 05-3 = SDBR-CMU 503 ) .

Additional GenBank numbers.

act and tef 1 for SDBR-CMU 502 : PQ 523738 and PQ 523739; tef 1 for SDBR-CMU 503 : PQ 523740.

Ecology and distribution.

Endolichenic fungi from the medulla of foliose lichen ( Parmotrema sp. ) in Thailand.

Notes.

Based on a blast search of the NCBI’s GenBank nucleotide database of the ITS sequence, Atrokylindriopsis racemosospora has the closest match with At. setulosa (strain HMAS 245592 ; KP 337330, ex-type) with 99.33 % similarity and is similar to Aciculomyces restrictus (strain FMR 18994 ; ON 009870 , ex-type) with 93.79 % similarity (identities = 468 / 499, 10 gaps) and Exophiala siamensis (strain SDBR-CMU 417 ; NR _ 184988, ex-type) with 92.39 % similarity (identities = 583 / 631, 16 gaps). The closest matches using the LSU sequence are At. setulosa (strain HMAS 245592 ; KP 337329) with 100 % similarity (identities = 548 / 548, 0 gap), Ex. ramosa (strain FMR 18632 ; ON 009933 , ex-type) with 98.97 % similarity (identities = 865 / 874, 1 gap), and Melanoctona tectonae (strain MFLUCC 12-0389; NG _ 059687) with 98.43 % similarity (identities = 879 / 893, 2 gaps). The closest matches using SSU sequence are Ex. siamensis (strain SDBR-CMU 417 ; ON 555826 ) with 99.53 % similarity (identities = 1055 / 1060, 1 gap), Capronia dactylotricha (strain CBS 604.96; NG _ 062636) with 98.45 % similarity (identities = 1082 / 1099, 1 gap), and E. yunnanensis (strain YMF 1.06739, ex-type) with 98.31 % similarity (identities = 1049 / 1067, 1 gap). The closest matches using the tub 2 sequence are Biscogniauxia arima (strain YMJ 122; AY 951672 ) with 93.08 % similarity (identities = 121 / 130, 1 gap) and B. mediterranea (strain ISN 9 LDC 31; OQ 942633) with 92.37 % similarity (identities = 121 / 131, 1 gap).

A combined multilocus-based phylogenetic analysis showed that both strains ( SDBR-CMU 502 and SDBR-CMU 503 ) of Atrokylindriopsis racemosospora formed sister taxon to At. setulosa ( HMAS 245592 , ex-type strain) with 100 % ML and 1 PP statistical support, and also clustered with Aciculomyces restrictus ( FMR 18994 , ex-type strain) with 95 % ML and 1 PP statistical support (Fig. 1 ). The ITS and LSU nucleotide sequence comparisons reveal 3 / 580 and 0 / 548 base pair differences with At. setulosa , respectively. In contrast, a comparison of ITS, LSU, tef 1, and tub 2 base pairs shows that At. racemosospora differs from Ac. restrictus by 34 / 494 bp of ITS, 8 / 770 bp of LSU, 38 / 158 bp of tef 1, and 108 / 430 bp of tub 2. The morphology of Atrokylindriopsis differs from that of Aciculomyces in having unbranched, macronematous conidiophores, monophialidic conidiogenous cells, pigmented, septate, setulate conidia ( Ma et al. 2015; Torres-Garcia et al. 2023). Atrokylindriopsis racemosospora shares similar features, including sympodial proliferation, denticulate conidiogenous cells, and aseptate, obovoid or subglobose conidia, with species Ac. restrictus ( Torres-Garcia et al. 2023) , but Ac. restrictus has longer conidiophores (10–153 × 1.4–2.9 µm vs 19–105.5 × 1.5–2.5 µm) and smaller conidia (2.5–5 × 1.8–3.3 µm vs 2–4 × 1.5–2.5 µm). Moreover, the conidiogenous cells and conidia formation of At. racemosospora is more abundant than that of Ac. restrictus , and the conidial scars are not conspicuous. In addition, At. setulosa differs from At. racemosospora by its larger, cylindrical to clavate or rounded-cuboid conidia, which have 4–5 longitudinal eusepta and are attached to the conidiogenous locus at the midpoint of their long side, appearing to form a ‘ T’ ( Ma et al. 2015). These morphological characteristics clearly distinguish At. racemosospora from Ac. restrictus and At. setulosa .

Figures

Figure 1. Phylogram generated from maximum likelihood analysis of members in Herpotrichiellaceae based on a combined ITS, LSU, SSU, and tub 2 sequence dataset. Bootstrap values ≥ 50 % MLBS and Bayesian posterior probabilities (PP) ≥ 0.90 are shown above nodes and defined as ML / PP. The tree is rooted to Cyphellophora laciniata (CBS 190.61) and C. suttonii (CBS 449.91). The fungal strains obtained in this study are blue. Ex-type strains are in bold. The scale bar represents the expected number of nucleotide substitutions per site.

Figure 2. Atrokylindriopsis racemosospora (SDBR-CMU 502, ex-type). A – F. Colonies on PDA, MEA, OA, PCA, CMD and CMA, respectively, after 48 d at 25 ° C; G, H. Conidiophores sporulating on PCA; I. Conidiophores sporulating on OA; J. Conidiophores sporulating on CMA; K, L. Conidiophores and conidia; M – N. Hyphal coil; O, P. Hyphal anastomosis; Q, R. Terminal chlamydospores; S – W. Conidiophores with conidiogenous loci; X – Y. conidia. Scale bars: 10 µm (G – J); 20 µm (K – L); 10 µm (M – Y).