Sirastachys guangdongensis C. F. Liao, K. D. Hyde & Doilom, 2025

Sirastachys guangdongensis C. F. Liao, K. D. Hyde & Doilom sp. nov.

Fig. 5 View Figure 5

Etymology.

The epithet “guangdongensis” refers to the locality, Guangdong Province, China, where the holotype was collected.

Holotype.

MHZU 23-0250 .

Description.

Saprobic on dead stem of Agave sisalana . Sexual morph: undetermined. Asexual morph: Colonies superficial on host substrate, erect, gregarious, visible as numerous black conidial masses. Conidiophores 105–170 × 3.5–7 µm (av. 140 × 5.5 μm, n = 30), macronematous, mononematous, erect, simple, unbranched, straight or slightly flexuous, subcylindrical, hyaline, 1–5 - septate, not constricted at septa, smooth-walled, or slightly verrucose, thick-walled, bearing 4–8 conidiogenous cells on the tip. Conidiogenous cells 6.5–12.5 × 4–5 µm (av. 10 × 4 μm, n = 30), enteroblastic, monophialidic, discrete, determinate, terminal, elongate doliiform to reniform, subhyaline to brown, smooth-walled, with a conspicuous collarette. Conidia 5–6 × 4–5 µm (av. 5.5 × 4 μm, n = 30), acrogenous, aggregating in slimy masses, obovoid, with a prominent hilum, aseptate, brown, pale olivaceous brown, black, smooth-walled.

Culture characteristics.

Colonies on PDA reaching 5.5–6.0 cm in two weeks at 28 ± 2 ° C, medium dense, flat, circular, cream from above; pale luteous from the reverse, with no pigmentation.

Material examined.

China • Guangdong Province, Guangzhou City, Zhongkai University of Agriculture and Engineering (23.10643 ° N, 113.28240 ° E, 20 m), on dead leaf of Agave sisalana Perr. ex Engelm. ( Agavaceae ), 17 November 2021, C. F. Liao & Y. H. Yang, JM 02 ( MHZU 23-0250 , holotype) • ex-type, ZHKUCC 23-1003 GoogleMaps • ibid., living culture ZHKUCC 23-1004 GoogleMaps .

Notes.

Sirastachys guangdongensis resembles Si. pandicola and Si. Phaeospora that were described by Lombard et al. (2016). However, the former can be distinguished by the size of the conidiophores and conidia as well as other conidiophore characteristics. Sirastachys guangdongensis has longer conidiophores (105–170 µm) than those of Si. pandicola (55–75 µm) and Si. phaeospora (40–65 µm). Sirastachys guangdongensis has larger conidia (5–6 × 4–5 µm) than Si. pandicola (3–4 × 2–3 µm) and Si. phaeospora (4–5 × 2–3 µm). Conidiophores of Si. guangdongensis are 1–5 - septate, while they are 1–3 - septate in Si. pandicola and 1–2 (– 3) - septate in Si. phaeospora . Branched conidiophores are observed in Si. phaeospora ( Lombard et al. 2016) , while they are unbranched in Si. guangdongensis . The phylogenetic analyses supported Si. guangdongensis as a distinct species from other Sirastachys species and showed that Si. guangdongensis ( ZHKUCC 23-1003 and ZHKUCC 23-1004 ) formed a distinct branch and sister to Si. phaeospora (ex-type CBS 100155) with 99 % ML bootstrap support and 1.00 BYPP (Fig. 1 View Figure 1 ). Based on distinct morphological and molecular evidence, we propose Sirastachys guangdongensis as a novel species.