Moelleriella raciborskii (Zimm.) P. Chaverri, M. Liu & K.T. Hodge, Stud. Mycol. 60: 3 (2008)
Index Fungorum number: IF 539558; Facesoffungi number: FoF 13949
Parasitic on scale insects or whiteflies. Sexual morph: Stromata 2–3.6 (x̄ = 2.6 × 5, n = 5) mm, sessile, yellow, tubercular, superficial, scattered. Perithecia 240–560 × 180–300 (x̄ = 360 × 246, n = 10) μm, flask-shaped or ellipsoidal, ostiolate, superficial. Peridium 30–45 (x̄ = 33, n = 20) μm, comprised of hyaline cell of texture angularis. Paraphyses absent. Asci 200–400 × 6–16 (x̄ = 300 × 10, n = 20) μm, cylindrical, with a thickened apex. Ascospores 10–15 × 2–3.2 (x̄ = 13 × 2.5, n = 20) μm, hyaline, ellipsoidal to slightly fusiform, aseptate. Asexual morphs: Stromata up to 0.5–1.5 mm in diam., sessile, yellow, flatly pulvinate, scattered. Conidiomata immersed. Conidiomatal wall composed of hyaline cells of textura epidermoidea. Paraphyses absent. Conidiophores cylindrical, terminally or internally bearing whorl of phialides. Phialides 11–19 × 1–2.5 (x̄ = 14 × 1.7, n = 30) μm, hyaline, cylindrical, straight, aseptate, holoblastic. Conidia 10–15 × 1.4–2.6 (x̄ = 12 ×2, n = 30) μm, hyaline, fusiform, aseptate, smooth-walled, first conidium becoming conidiogenous by apically wall-building to form an unbranched chain.
Culture characteristics – Colonies on PDA reaching 2.2 cm after 30 days at 30 °C, white to pale yellow, surface minutely velvety, wrinkled, reverse yellow, conidial mass yellow, fluid.
Material examined – Thailand, NaKhon Si Thammarat Province, Lan Saka District, Kam Lone (99°46'37"E, 8°27'6"N, elevation 180 m), on scale insects attached to decayed leaves of a dicotyledonous plant, 27 April 2019, De-Ping Wei, HC03 (MFLU 22-0262), living culture MFLUCC 22-0184. Chiang Mai Province, Mushroom researcher centre, on scale insects attached to living leave of a dicotyledonous plant, 13 August 2020, De-ping Wei, MRC0851B (MFLU 22-0261), living culture MFLUCC 22-0191.
Molecular data – MFLU 22-0262: LSU (OQ127372), SSU (OQ127301), ITS (OQ127337), TEF (OQ186364), RPB1 (OQ186418), RPB2 (OQ186394). MFLU 22-0261: LSU (OQ127373), SSU (OQ127302), ITS (OQ127338), TEF (OQ186365), RPB1 (OQ186419), RPB2 (OQ186395).
Notes – Hypocrella raciborskii was revisited by Liu et al. (2006) in which the authors provided the updated morphological description and linked its asexual morphs to Aschersonia placenta. Hypocrella raciborskii later was transferred to Moelleriella by Chaverri et al. (2008). The most distinctive character of M. raciborskii is the formation of tubercles on pulvinate stroma, inside which a single perithecium is embedded. The multigene phylogenetic analysis reveals a robust clade of our specimens (MFLU 22-0262 and MFLU 22-0261) and M. raciborskii (P. C 533). The sexual specimen (MFLU 22-0262) fits well with the concept of M. raciborskii in producing the tuberculate stromata and filiform ascospores, which break into many cylindrical fusiform secondary ascospores inside the asci. The asexual specimen (MFLU 22-0261) is diagnosed as the asexual morph of M. raciborskii based on phylogenetic evidence, its pulvinate stroma and the aschersonia-like conidiophore.
Fig. 9 – Moelleriella raciborskii (MFLU 22-0262, a–l), (MFLU 22-0263, m–s). a Stroma on substrate. b, c, s Upper and lower view of culture. d–f Perithecia. g–i Asci. j–l Ascospores. m Conidioma. n–q Conidiophores and phialides. r Conidia. Scale bar: m = 1000 μm, d–f = 300 μm, g–i = 100 μm, n–q = 20 μm, j–l, r = 10 μm.
Wei DP, Gentekaki E, Wanasinghe DN, Karunarathna SC, Tang SM, Hyde KD 2022 – Diversity, molecular dating and ancestral characters state reconstruction of entomopathogenic fungi in Hypocreales. Mycosphere 13: 281–351.
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