Sphaerellopsis
Sphaerellopsis Cooke, Grevillea 12(no. 61): 23 (1883)
Facesoffungi number: FoF 07596
Dothideomycetes, Pleosporomycetidae, Pleosporales, Leptosphaeriaceae
Parasitic on rust fungi. Sexual morph: Ascomata dark brown to black, stromatic, solitary to gregarious, immersed to semi-immersed, subglobose to irregular, unilocular, glabrous, ostiolate. Ostiole papillate, single, centrally located. Peridium composed of brown to dark brown, thin-walled cells of textura angularis at the basal and lateral part, becoming slightly thickened towards upper part. Hamathecium composed of numerous pseudoparaphyses and asci. Pseudoparaphyses cylindrical, branched, septate, frequently anastomosing, embedded in mucilaginous matrix. Asci 8-spored, bitunicate, fissitunicate, cylindrical-clavate, pedicellate, apically rounded, with an indistinct ocular chamber. Ascospores pale brown or pale honey-yellow, regularly biseriate, spindle-shaped, with narrow and obtuse ends, 2–3-septate, constricted at septa, slightly inequilateral, smooth-walled (Spegazzini 1908, Yuan et al. 1998). Asexual morph: Conidiomata dark brown to black, pycnidial, occasionally solitary, mostly gregarious or confluent, immersed to semi-immersed, unilocular or multilocular, glabrous, with locule globose or pyriform, thick-walled, ostiolate. Ostiole cylindrical, centrally located. Conidiomatal wall composed of pale brown to hyaline cells of textura angularis to textura prismatica. Conidiophores lining the cavity of the conidiomata, mostly reduced to conidiogenous cells, hyaline, cylindrical or doliiform, septate, branched, invested in mucus. Conidiogenous cells of two kinds: a) those producing macroconidia, arising from the basal and lateral zone, hyaline, enteroblastic, ampulliform to doliiform, subcylindrical or irregular, smooth-walled, discrete or integrated, with or without percurrent proliferations; b) those producing microconidia, restricted to the area around the ostiolar channel, hyaline, ampulliform, smooth-walled. Macroconidia hyaline, fusiform to ellipsoidal, Y-shaped or digitate, septate, smooth-walled, bearing mucoid appendages at each end or only at one end. Microconidia short-cylindrical to ellipsoidal or subglobose, unicellular, colourless, smooth-walled.
Type species: Sphaerellopsis filum (Biv.) B. Sutton, Mycol. Pap. 141: 196 (1977)
Notes: Sphaerellopsis filum was originally described by Bivona-Bernadi (1813–16) from rust fungi on Convolvulus sepium and Populus nigra in Sicily. This species is a well-known mycoparasite associated with approximately 370 species and 30 genera of rusts, occurring in more than 50 countries (Kranz and Brandenburger 1981). Sphaerellopsis filum has been shown to colonize rust pustules and suppress rust spore production (Yuan et al. 1999). Due to this fact it has been regarded as a potential biocontrol agent (Morris et al. 1994, 1995, Kuhlman et al. 1978, Whelan et al. 1997, Pei et al. 2003, Płachecka 2005). However, little is known of the population biology and genetic diversity of S. filum.
Distribution: worldwide.
References:
Li WJ, McKenZie EHC, Liu JK, Bhat DJ, Dai DQ, Caporesi E, Tian Q, Maharachcikumbura SSN, Luo ZL, Shang QJ, Zhang JF, Tangthirasunun N, Karunarathna SC, Xu JC, Hyde KD (2020) Taxonomy and phylogeny of hyaline-spored coelomycetes. Fungal Diversity 100: pages279–801.
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