Ascomycota, genera » Ascomycota, incertae sedis

Monochaetiella

Monochaetiella E. Castell., Nuovo G. bot. ital. 49: 487 (1943) [1942]

Facesoffungi number: FoF 07450

Ascomycota, genera incertae sedis

 

Parasitic on leaves of Hyparrhenia cymbaria, H. cymbaria, H. filipendula, H. rufa, H. variabilis, Hyparrhenia spp. (Poaceae) (Nag Raj 1993). Sexual morph: undetermined. Asexual morph: Conidiomata dark brown to black, acervular, solitary or confluent, epidermal to subepidermal, immersed, linear, unilocular, glabrous. Ostiole absent, dehiscence by irregular splits of apical wall. Conidiomatal wall composed of thin-walled, pale brown to brown cells of textura prismatica in the base wall, merging with thick-walled, brown to dark brown cells of textura angularis to textura globulosa in the lateral wall. Conidiophores reduced to conidiogenous cells. Conidiogenous cells arising from the inner wall layer of the basal stroma, pale brown, with verruculose walls in the basal part, becoming thin-walled, paler and smooth above, enteroblastic, phialidic, lageniform to subcylindrical or cylindrical, discrete, determinate. Conidia hyaline, fusiform to navicular, truncate at the base, unicellular, smooth-walled, guttulate, bearing a cellular, tubular, apical appendage (Sutton and Dicosm 1977, Nag Raj 1993).

 

Type species: Monochaetiella hyparrheniae E. Castell., Nuovo G. bot. ital. 49: 487 (1943) [1942]

 

Notes: Kandaswamy and Sundaram (1957) and Punithalingam (1969) described two taxa from graminicolous hosts in India, namely, M. themedae M. Kandasw. & Sundaram and M. cymbopogonis Punith. & Sarwar. Sutton and Dicosm (1977) revised Monochaetiella and showed that M. themedae and M. cymbopogonis were distinct from the type species in conidiogenous cells and conidia. They proposed a new genus, Monochaetiellopsis B. Sutton & DiCosmo to accommodate these two species, and designated M. themedae as the generic type. This concept was followed by later authors (Sutton 1980, Nag Raj 1993). Monochaetiella is monotypic. The type species Monochaetiella hyparrheniae was associated with leaf lesions on Hyparrhenia rufa in Ethiopia.

Monochaetiella has hyaline, fusiform to navicular conidia bearing an apical appendage, which can be confused with Ciliosporella, Monochaetiellopsis and Tracylla (T. aristata). However, Ciliosporella has pycnidial, multilocular conidiomata with paraphyses, which differs from the acervular conidiomata in Monochaetiella and Monochaetiellopsis. Tracylla possesses superficial, pycnothyrial conidiomata with a shield connected to the immersed mycelium by a central supporting column of cells, which is different from other three genera (Nag Raj 1993). Monochaetiellopsis can be distinguished from Monochaetiella by its sympodial conidiogenous cells and 1–2-septate conidia with septa close to the base and apex. No molecular data is available for Monochaetiella, and fresh collections are needed to place it in a natural classification.

 

Distribution: Ethiopia, Sudan, Uganda, Zambia (Nag Raj 1993).

 

 

Monochaetiella hyparrheniae (redrawn from Morgan-Jones 1977) a Conidia. b Partial view of vertical section of conidioma. c Conidiogenous cells and

 

 

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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