Chaetomium rectangulare Asgari & Zare, Mycologia

Juxu, Rong, Phukhamsakda, Chayanard & Boonmee, Saranyaphat, 2024, Identification of a new species and three new records of Chaetomiaceae associated with commercial herbal teas in northern Thailand, Phytotaxa 653 (2), pp. 134-154 : 146-148

Chaetomium rectangulare Asgari & Zare, Mycologia 103(4): 872 (2011) ( Fig. 7 ), new host record and geographical distribution

Index Fungorum number: IF519103, Facesofungi numbe r: FoF15768

Culture characteristics:—Colonies growing on PDA, reaching 3–4 cm diam., in 2 weeks at 25 °C in the dark condition, effuse to slightly fluffy, radially striate with fimbriate edge, white to yellowish, covered by black ascomatal structure, with yellow pigmented in medium. Mycelium superficial, hyaline to light brown, branched, septate, smooth-walled. Ascomata produced in culture within 4 weeks.

Sexual morph: Ascomata 150–316.5 µm diam., superficial, uniloculate, solitary, subglobose, dark brown to black, covered by dense hairs, with dark brown, hyphal rhizoid at the base, ostiole. Peridium composed of dark brown cells; paraphyses not seen. Terminal-lateral hairs 3–5 µm wide, straight to slight curve, with or without branched, dark brown, septate, verrucose-walled. Asci thin-walled and quickly evanescent, unable to be observed. Ascospores 10.5–13 × 8–9 µm (x = 11 × 8 µm, n = 10), limoniform, ellipsoid to broad fusiform, symmetrical or asymmetrical ends, olivaceous brown, with two apical germ pores, aseptate, guttulate, externally smooth, roughened on the inner surface. Asexual morph: Undetermined.

Material examined:— THAILAND, Chiang Mai Province, Muang, Warorot market, black goji berry tea ( Lycium ruthenicum , Solanaceae ), 2 March 2023, Saranyaphat Boonmee, HBT43A (MFLU 24–0087, dried culture, new host record and geographical distribution), living cultures MFLUCC 24–0070.

Notes:— Chaetomium rectangulare was proposed by Asgari & Zare (2011) which was isolated from the leaf of barley ( Hordeum vulgare ) and seed of wheat ( Triticum aestivum L.) in Iran, whereas its asexual morph was reported as acremonium-like. Our new collection of Ch. rectangulare (MFLUCC 24–0070) was isolated from black goji berry tea specimens from the local market in Chiang Mai. Our isolate ( Fig. 7 ) shares similar characteristics of subglobose, black ascomata, surrounded by densely with dark ascomatal hairs and ellipsoid to broad fusiform, aseptate, olivaceous brown ascospores identical to the ex-type strain IRAN 1641C ( Asgari & Zare 2011, Fig. 5 ). Phylogenetic analysis of combined ITS, RPB2 and TUB2 sequence data place our isolated consistently clustered basal to the clade of Ch. rectangulare strains ( IRAN 1639C and IRAN 1641C) with 100% ML, 1.00 PP statistical support ( Fig. 5 ). Therefore, we report our isolated MFLUCC 24–0070 as a new host record and new geographical distribution of Ch. rectangulare from black goji berry tea product from northern Thailand.

Figures

FIGURE 5. Phylogram generated from RAxML analysis based on combined ITS, RPB2 and TUB2 sequence data of Chaetomium taxa. Xanthiomyces spinosus isolates CBS 789.71 and CBS 796.83 are selected as the outgroup taxa. Bootstrap support values for ML values equal to or>70% and PP values equal to or>0.95 are shown as ML/PP above the nodes. Newly generated sequences in this study are in blue. Type strains are indicated in bold.

FIGURE 7. Chaetomium rectangulare (MFLUCC 24–0070, new host record and geographical distribution). a Black goji berry tea. b, c Culture colony on PDA after one month from surface and reverse. d, e Ascomata on top and side views surrounded by dark dense hairs. f Squash mouth of ascoma with basal hyphae in water. g Close-up of ascomatal hairs. h, i Ascospores. Scale bars: d, e = 500 µm, f = 50 µm, g–i = 10 µm.