Phylogenetic placement of Iodosphaeriaceae (Xylariales, Ascomycota), designation of an epitype for the type species of Iodosphaeria, I. phyllophila, and description of I. foliicola sp. nov.

Abstract

The Iodosphaeriaceae is represented by the single genus, Iodosphaeria, which is composed of nine species with superficial, black, globose ascomata covered with long, flexuous, brown hairs projecting from the ascomata in a stellate fashion, unitunicate asci with an amyloid apical ring or ring lacking and ellipsoidal, ellipsoidal-fusiform or allantoid, hyaline, aseptate ascospores. Members of Iodosphaeria are infrequently found worldwide as saprobes on various hosts and a wide range of substrates. Only three species have been sequenced and included in phylogenetic analyses, but the type species, I. phyllophila, lacks sequence data. In order to stabilize the placement of the genus and family, an epitype for the type species was designated after obtaining ITS sequence data and conducting maximum likelihood and Bayesian phylogenetic analyses. Iodosphaeria foliicola occurring on overwintered Alnus sp. leaves is described as new. Five species in the genus form a well-supported monophyletic group, sister to the Pseudosporidesmiaceae in the Xylariales. Selenosporella-like and/or ceratosporium-like synasexual morphs were experimentally verified or found associated with ascomata of seven of the nine accepted species in the genus. Taxa included and excluded from Iodosphaeria are discussed.

Three new species of Iodosphaeria (Xylariomycetidae): I. chiayiensis, I. jinghongensis and I. thailandica

“…In 15 years of studying fungi in Hong Kong, only a single collection was found despite intensive collection efforts (Taylor and Hyde 1999). Iodosphaeria is widely distributed in temperate and tropical regions, e.g., China (Guizhou, Yunnan), Europe (Belgium, Germany), Great Britain, Canada, Hong Kong, New Zealand, South America (Brazil, Argentina, French Guiana), Taiwan and USA (Louisiana) (Samuels et al 1987;Barr 1993;Hyde 1995;Candoussau et al 1996;Hsieh et al 1997;Taylor and Hyde 1999;Catania and Romero 2012;Li et al 2015;Marasinghe et al 2019;Miller and Réblová 2021). This genus is saprobic on dead plant substrates in terrestrial grassland habitats (Barr 1993), on fern rachides (Samuels et al 1987), on dead petioles of palms (Taylor and Hyde 1999), and on submerged wood in freshwater (Hyde 1995) but has never been reported as pathogenic on hosts.…”

“…Only five of the nine Iodosphaeria species have been sequenced (Li et al 2015;Marasinghe et al 2019;Miller and Réblová 2021) and several species of them lack DNA-based sequence data. The sexual morph of Iodosphaeria is characterized by superficial, black, apapillate ascomata with unbranched, brown radial flexuous hairs, a two layered peridium composed of a pigmented outer layer and a hyaline inner layer; unitunicate, amyloid or non-amyloid, cylindrical to narrowly clavate, 8-spored asci; and mostly allantoid to ellipsoidal, aseptate, hyaline ascospores with or without a gelatinous sheath (Miller and Réblová 2021). The asexual morphs of Iodosphaeria are considered selenosporella-like or ceratosporium-like (Samuels et al 1987;Li et al 2015;Miller and Réblová 2021).…”

“…The sexual morph of Iodosphaeria is characterized by superficial, black, apapillate ascomata with unbranched, brown radial flexuous hairs, a two layered peridium composed of a pigmented outer layer and a hyaline inner layer; unitunicate, amyloid or non-amyloid, cylindrical to narrowly clavate, 8-spored asci; and mostly allantoid to ellipsoidal, aseptate, hyaline ascospores with or without a gelatinous sheath (Miller and Réblová 2021). The asexual morphs of Iodosphaeria are considered selenosporella-like or ceratosporium-like (Samuels et al 1987;Li et al 2015;Miller and Réblová 2021). Members of Iodosphaeria are regarded as cosmopolitan species (Li et al 2015).…”

“…Members of Iodosphaeria are regarded as cosmopolitan species (Li et al 2015). These species are usually saprobic on dead branches, twigs, stems, and petioles of economically important plants, such as Alnus sp., Archontophoenix alexandrae, Arundinaria sp., Corylus sp., Cyathea dealbata, Podocarpus parlatorei, Polygonum chinense and Ripogonum scandens (Samuels et al 1987;Barr 1993;Hyde 1995;Candoussau et al 1996;Hsieh et al 1997;Taylor and Hyde 1999;Catania and Romero 2012;Li et al 2015;Miller and Réblová 2021), but have never been reported as pathogens (Hyde et al 2020a). Samuels et al (1987) accepted Iodosphaeria in Amphisphaeriaceae, and later, various authors placed it in Lasiosphaeriaceae and Trichosphaeriaceae (Barr 1990(Barr , 1994Kang et al 1998;Hilber and Hilber 2002;Jeewon et al 2003).…”

“…Hongsanan et al (2017) treated it as Xylariomycetidae family incertae sedis, while Hyde et al (2020a) and accepted Iodosphaeriaceae in Amphisphaeriales. In the most recent study of Miller and Réblová (2021), Iodosphaeriaceae is accounted as a family in Xylariales.…”