Sporidesmium tropicale M. B. Ellis

Sporidesmium tropicale M. B. Ellis , Mycol. Pap. 70: 58 (1958)

Fig. 4 View Figure 4

Host.

Pinus yunnanensis Franch.

Description.

Saprobic on submerged decaying branch of Pinus yunnanensis . Sexual morph: undetermined. Asexual morph: Colonies on superficial substratum, scattered, hairy, effuse, and black. Mycelium mostly immersed, composed of septate, branched, pale black, and smooth-walled hyphae. Conidiophores 76–392 × 4–8 µm (av. = 239 × 7.0 µm, n = 30), macronematous, mononematous, unbranched, cylindrical, erect, straight or slightly flexuous, single, 5–17 - septate, dark brown, paler towards apex, smooth, and thick-walled. Conidiogenous cells 4–11 × 3–5 µm (av. = 6.1 × 4.0 µm, n = 30), monoblastic, holoblastic, terminal, integrated, cylindrical, and dark-brown. Conidia 65–134 × 12–16 µm (av. = 105 × 14.8 µm, n = 30), acrogenous, solitary, dry, pyriform, rostrate, obclavate, with a long and slender apex, straight or slightly curved, tapering to the apex, 3–5 µm wide and truncate at the base, dark brown, pale brown, 2–5 µm wide at the apex, 11–17 - septate, thick-walled, and with the proximal part usually verrucose.

Material examined.

China • Yunnan Province, Wumengshan National Nature Reserve ( 28°19'29.79"N, 104°00'05.48"E), altitude: 1361 m, on Pinus yunnanensis Franch. , decaying wood, 22 July 2024, Qinfang Zhang, 2024 WMS 80 About WMS ( GMB 5105 ) GoogleMaps . China • Yunnan Province, Wumengshan National Nature Reserve ( 28°19'15.23"N, 104°0'16.31"E), altitude: 1373 m, on dry wood, 22 July 2024, Qinfang Zhang, 2024 WMS 96 About WMS ( GMB 5109 ) GoogleMaps .

Notes.

In the phylogram (Fig. 1 View Figure 1 ), our collections ( Sporidesmium tropicale GMB 5105 and GMB 5109 ) clustered with S. tropicale (DLUCC- 1689) with strong statistical support ( ML / BY: 100 / 1). DNA sequence comparisons revealed high similarity to S. tropicale (DLUCC- 1689), with 99.38 % identity in the ITS, 100.00 % in the LSU, and 99.71 % in the rpb 2 gene. However, noticeable morphological differences were observed when compared to both the original description by Ellis (1958) and the description provided by Bao et al. (2021), particularly in the size of the conidiophores and conidia.

The conidiophores in our collection ( S. tropicale GMB 5105 ) are longer (76–392 × 4–8 µm) than those reported by Bao et al. (2021) for S. tropicale (DLUCC- 1689) (71–163 × 5–8 µm), while the conidia are slightly smaller (65–134 × 12–16 µm vs. 94–184 × 13–15 µm). In the original description by Ellis (1958), S. tropicale was characterized by even longer conidiophores (40–340 µm) and larger conidia (80–230 µm), highlighting the morphological variability. These differences may be attributed to environmental factors such as geography, humidity, temperature, or the developmental stage of the specimens. However, the morphological characteristics of our specimens fall within the range of the features described in the original description by Ellis (1958). Previously, S. tropicale has been reported on dead branches of various dicotyledonous plants, including Averrhoa carambola , Blighia unijugata , Camellia sinensis , Psidium guajava , Chrysophyllum albidum , Cola nitida , Dillenia indica , Hevea brasiliensis , Glyphaea brevis , Homalium aylmeri , Lecaniodiscus cupanioides , Ochthocosmus africanus , Parinari excelsa , Phyllanthus discoideus , and Pimenta officinalis . In this study, we report S. tropicale on a new host monocot plant, Pinus yunnanensis . The strain GMB 5105 is therefore designated as a new host record.