Corynespora torulosa (Syd. & P. Syd.) Crous, Persoonia 31: 211 (2013)
Index Fungorum number: IF 805829; Facesoffungi number: FoF 14164; Fig. 1
Saprobic on dead leaves of Musa sp. Sexual morph: Undetermined. Asexual morph: Colonies effuse, grey, brown or black, often hairy. Mycelium immersed, occasionally superficial. Stroma none. Setae and hyphopodia absent. Conidiophores erect from the mycelium, 110–220 µm × 1–14 µm (x̅ = 137.5 × 9.8 µm, n = 30), 9–12 μm wide at the base, 1–3 μm near the apex, arising singly, simple, torsive, straight or flexuous, unbranched, pale brown to dark brown, septate, 4–5 thin flange tissue parts appearing as wings on the surface. Conidiogenous cells monoblastic, integrated, terminal, percurrent, doliiform, collarette, producing hyaline spherical immature conidia at terminal end. Conidia 60–80 µm × 10–17 µm (x̅ = 65.2 × 12.5 µm, n = 50), with blackish brown scar at the base, formed singly, cylindrical, straight or slightly curved, tapering towards rounded apex, mid brown or golden brown, smooth or verruculose, aseptate or 1–multi transverse pseudosepta, thin flange tissue part attached to the surface of the conidia like a wing at the apex of some conidia.
Culture Characteristics – Colonies on PDA at 25° C and under light reach 5 cm diameter in 6 days, initially greyish white, mouse grey or white and becoming brownish black at maturity. Filamentous, or rhizoid form, raised. Margin entire, lobate or ciliate
Material examined – Thailand, Chiang Rai Province, Nang Lae, on a dead banana leaf, 20 March 2019, Binu C. Samarakoon, BNS213 (MFLU 17-1773), living culture MFLUCC 23-0030.
GenBank numbers – LSU: OQ947166, ITS: OQ947171.
Known distribution (based on molecular data) – Cosmopolitan distribution (Kumar & Singh 2021).
Known hosts (based on molecular data) – Costus comosus, Heliconia bihai, Ravenala madagascariensis, Musa spp. (Kumar and Singh 2021).
Notes – Corynespora torulosa, previously known as Deightoniella torulosa (= Brachysporium torulosum), was accommodated in the Corynesporascaceae by Crous et al. (2013) based on molecular data. The fungus has been reported to cause black leaf spots on banana leaves in Georgia, India, Jamaica, and Thailand (Meredith 1962, Koné et al. 2008). In addition, C. torulosa was reported to cause fruit speckles on banana fruits at the pre-harvest stage in Jamaica and Cuba (Meredith 1962, Almenares & Pérez-Vicente 2019). Corynespora torulosa also has saprobic and endophytic nutritional modes discovered in terrestrial habitats (Meredith 1962, Photita et al. 2001). In the multi-gene phylogeny (LSU and ITS), our isolates grouped with C. torulosa isolates with CATAS-XJCT97, CATAS-XJCT98 and CATAS-XJCT99 (Fig. 2). Our strain (Fig. 1) is similar in morphology to the illustration of Elis (1971). Based on morphology and solid molecular justifications, we document the occurrence of Corynespora torulosa associated with Musa sp. as a saprobe from Thailand.
Fig. 1 – Corynespora torulosa (MFLU 17-1773, new saprobic collection). a Colonies on host. b, d, e, f Conidiophores and conidia. g Attachment of conidia. c, h–l Conidia. Scale bars: a = 100 μm, f, g = 30 μm, b, d, e = 15 μm, c, h–l = 20 μm.
Fig. 2 – Phylogram generated from maximum likelihood analysis based on combined LSU and ITS sequence data for selected taxa in Pleosporales. Thirty-five strains are included in the combined analyses which comprised 1366 characters (808 characters for LSU and 458 characters for ITS) after alignment. Tree topology of the maximum likelihood analysis is similar to the Bayesian analysis. The best RaxML tree with a final likelihood value of -21969.93 is presented. The matrix had 1136 distinct alignment patterns, with 35.79% of undetermined characters or gaps. The evolutionary model GTR+I+G applied to both ITS and LSU regions. Bootstrap support values for ML greater than 60% and Bayesian posterior probabilities greater than 0.95 are given near nodes, respectively. The tree is rooted with Cyclothyriella rubronotata (CBS 141486 and CBS 121892). Ex-type strains are in bold. The newly generated sequences are indicated in yellow.