Dwiroopa Subram. & Muthumary, Proc. Indian Acad. Sci., Pl. Sci. 96(3): 196 (1986)
Diaporthomycetidae, Diaporthales, Dwiroopaceae, Dwiroopa
Saprobic or pathogenic on leaves, twigs, branches and fruits. Sexual morph: Undetermined. Asexual morph: Coelomycetous. Conidiomata pycnidial, immersed to semi-immersed, erumpent, solitary, uni- to multiloculate, scattered, globose, black, ostiolate or lacking ostioles. Peridium thick-walled, comprising wall of 3–6 layers of pale brown cells of textura angularis. Conidiophores lining the innermost wall layer of peridium, mostly reduced to conidiogenous cells. Conidiogenous cells holoblastic, ampulliform to subcylindrical, hyaline to pale brown, sometimes proliferating percurrently at apex. Conidia unicellular, solitary, truncate at base, of three types: Macroconidia solitary, dark brown, aseptate, granular at surface, guttulate, thick-walled, broadly ellipsoid to obovoid, with longitudinal striations running along the length of conidia. Mesoconidia hyaline to pale brown, ellipsoid, aseptate and microconidia ellipsoid, hyaline, aseptate (adapted from Xavier et al. 2019).
Type species: Dwiroopa ramya Subram. & Muthumary, Proc. Indian Acad. Sci., Pl. Sci. 96(3): 196 (1986)
Notes: Members of Dwiroopa resemble Harknessia in having uni- to multiloculate, thick-walled, immersed to semi-immersed conidiomata, becoming erumpent, dark brown and aseptate, thick-walled macroconidia with holoblastic conidiogenesis, with conidiogenous cells bearing periclinal thickenings. Dwiroopa is distinguished from Harknessia in having distinct, holoblastic conidiogenesis, thick-walled conidiogenous cells and broadly spaced several longitudinal striations in the macroconidia, lacking a basal appendage and showcasing a dark scar with minute marginal frills at the conidial connection. Harknessia is distinct from Dwiroopa in having macroconidia that are smooth-walled or have closely spaced longitudinal raised bands on only one side and usually with a true basal appendage. Furthermore, Dwiroopa produces three different kinds of conidia viz. macroconidia, mesoconidia and phialoconidia (Farr & Rossman 2003), which are not produced in Harknessia. Farr & Rossman (2003) redescribed Dwiroopa ramya and designated it as a lectotype and also introduced Harknessia lythri as Dwiroopa lythri in Dwiroopa based on morphological similarities.
Species illustrated in this entry
Dwiroopa ramya Subram. & Muthumary
Farr DF, Rossman AY. 2003 – Dwiroopa, a coelomycetous genus with two species. Mycoscience 44, 443–446.
Xavier KV, KC AN, Crous PW, Groenewald JZ, Vallad GE. 2019 – Dwiroopa punicae sp. nov. (Dwiroopaceae fam. nov., Diaporthales), associated with leaf spot and fruit rot of pomegranate (Punica granatum). Fungal Systematics and Evolution 4, 33–41. 1056.