Colletotrichum orchidophilum Damm, P.F. Cannon & Crous

Ma, Xiaoya, Nontachaiyapoom, Sureeporn, Jayawardena, Ruvishika S., yde, Kevin D., Gentekaki, Eleni, Zhou, Sixuan, Qian, Yixin, Wen, Tingchi & Kang, Jichuan, 2018, Endophytic Colletotrichum species from Dendrobium spp. in China and Northern Thailand, MycoKeys 43, pp. 23-57 : 39-40

Colletotrichum orchidophilum Damm, P.F. Cannon & Crous Figure 10

Description.

Sexual morph not observed.

Sexual morph not observed. Asexual morph on SDA. Vegetative hyphae 1.9-5.4 µm diam, smooth-walled, septate, branched, hyaline to pale brown. Chlamydospores not observed. Appressoria brown, smooth-walled. Conidiomata superficial or under mycelia, smooth-walled, 200 × 300 µm, black. Conidiophores smooth-walled, branched or unbranched, hyaline. Conidiophores and appressoria rare. Conidia (9.6-) 11.7-14.1 (-14.7) × (2.9-) 3.5-4.4 (-4.8) µm, L/W = 3.3, cylindrical, straight, with 1 to 4 guttules, one end somewhat acute, hyaline.

Cultures on SDA flat with entire margin. Growth rate: 0.44cm/day, with nearly 20-days for sporulation. White with dark green mycelia around the middle, white edge, reverse white. Cultures on PDA flat with entire margin. Growth rate: 0.45cm/day, with 30-days for sporulation. Fluffy, white, reverse light brown. Acervuli in mass black, irregular, asymmetrical, merging in media.

Notes.

Strains MFLUCC–14– 0161 and MFLUCC–14– 0162 belong to a single species as they have similar conidia, cultures and the nearly identical sequence data. The support values of 100/1.00/100 totally grouped them with C. orchidophilum and their branch lengths are slightly different. Blastn researches sequences of MFLUCC 14-0161 and MFLUCC 14-0162 results in 99% identity with ITS (GenBank NR111729), GAPDH (GenBank JQ948481) and ACT (GenBank JQ949472) sequences of ex-holotype culture of C. orchidophilum strain CBS 632.80 isolated form Dendrobium sp. in USA (Damm et al. 2012). TUB2 sequence is 99% identity with pathogenic C. fructicola strain AV24 (GenBank KX786459) isolated from grapevine shoots in Brazil (Santos et al. 2018) and C. gloeosporioides strain TL-2 (GenBank KC913205) isolated from Camellia sinensis in China ( Guo et al. 2014). Because no conidiophores were detected in culture, no measurement for the conidiophores could be given. In this study, strains MFLUCC 14-0161 and MFLUCC 14-0162 of C. orchidophilum were isolated from leaves of D. harveyanum .