Capnodium coartatum Chomnunti & K.D. Hyde

Haituk, Supitchakorn Thungdee Sukanya, Withee, Patchareeya, Cheewangkoon, Ratchadawan, Suwannarach, Nakarin, Marasinghe, Diana S. & Hongsanan, Sinang, 2023, Unraveling Capnodiaceae species in Northern Thailand, Phytotaxa 620 (2), pp. 143-156 : 148

Capnodium coartatum Chomnunti & K.D. Hyde ,

in Chomnunti et al., Fungal Diversity 51(1): 117 (2011)

Index Fungorum number: IF563362 ( FIGURE 2 )

Colonies saprobic sooty mold-like, growing on leaves of Carica papaya L. Thallus dark brown to black, dense, easily removed from the host, composed of dark brown to brown, septate hyphae ( FIGURE 2a, b ). Sexual morph: Not observed. Asexual morph: Pycnidia 230–312 × 25–40 μm (x = 278 × 32 μm, n = 10), scattered or gregarious, blackish brown or slightly greenish, synnematous in structure, ovoid to flask-shaped, elongate, somewhat branched, comprising mostly cylindrical cell, with slight swollen or flattened base ( FIGURE 2d, f, g ). Ostiole surrounded by hyaline hyphae ( FIGURE 2e ), upper cylindric region tapering to apex. Conidia 3.9–5.6 × 1.9–2.7 μm (x = 4.6 × 2.3 μm, n = 15), ellipsoidal, smooth, round ends, hyaline, produced within the base of pycnidia, gathering in a terminal droplet on ostiole ( FIGURE 2h ).

Material examined: THAILAND, Payao Province, on living leaf of Carica papaya L. ( Caricaceae ), 29 October 2022, N Suwannarach SDBR-CMUPPY01.1= CMUB40023, living culture SDBR-CMU477.

Notes: Our sooty mold collection was found on living leaves of Carica papaya . On a single leaf specimen, we observed 2–3 carcasses of aphids and scale insects. However, it remains challenging to definitively identify which of these insects serves as the primary source of sugar excretions, which are nutritional resources for Capnodium coartatum . In phylogenetic analysis ( FIGURE 1 ), our strain (SDBR-CMU477) grouped with other strains of Ca. coartatum (CPC1779, MLFUCC10-0070, and MLFUCC10-0069), with 70% ML and 0.93 PP support ( FIGURE 1 ). Our strain (SDBR-CMU477) is morphologically identical to Ca. coartatum . However, it has shorter and slightly thinner pycnidia compared to the type material of Ca. coartatum described by Chomnunti et al. (2011) (230–312 × 25–40 vs. 332–401 × 34–56 μm). All these specimens have longer pycnidia than those of CPC1779, identified as Ca. coartatum by Abdollahzadeh et al. (2020) (115–203 μm high). Moreover, the pycnidia of SDBR-CMU477 has a blackish brown or slightly greenish color, while the pycnidia of the other strains have been reported as blackish brown pycnidia. Although there are minor variations between our strain and others in the size and color of pycnidia, the multigene-phylogenetic analysis conducted in this study indicates that they are identical. Therefore, our collection is the first report of Ca. coartatum from Carica papaya .

Figures

FIGURE 1 Phylogram of the best-scoring ML consensus tree based on a combined dataset (LSU, ITS, tef-1α and rpb2) of Capnodiaceae. Sequences obtained in this study are indicated in red, and newly established species are indicated in yellow. Isolates from type materials are in bold. The ML ultrafast bootstrap and Bayesian PP values equal to or greater than 60% and 0.90 are shown at the nodes. The tree is rooted with Scorias leucadendri (CBS 131318) and S. spongiosa (CBS 325.33).

FIGURE 2 Capnodium coartatum (CMUB40023) a, b Sooty mold on the leaf surface of Carica papaya L. c Appearance of conidiomata on the host surface. d Stalked pycnidia. e Ostiole surrounded by hyaline hyphae. f Pycnidia wall. g Immature conidiomata h Conidia. i Germinating conidia. Scale bars: d = 100 µm, e–g = 50 µm, h = 10 µm, i = 20 µm.