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Home • Dichotomocladium robustum RSA 2353+ v1.0
Figures 1 and 2: Sporangiophores that bear unispored sporangiola in terminal heads composed of dichotomously branching fertile hyphae. Images by Kerry O'Donnell
Figures 1 and 2: Sporangiophores that bear unispored sporangiola in terminal heads composed of dichotomously branching fertile hyphae. Images by Kerry O'Donnell

Dichotomocladium robustum Benny & R.K. Benj. (strain RSA 2353+) is classified within the family Lichtheimiaceae [order Mucorales, phylum Mucoromycota; Spatafora et al. 2016].  This genus was originally placed in the Thamnidiaceae (Benny and Benjamin 1975); however, molecular phylogenetic analyses of multilocus DNA sequence data revealed this family is polyphyletic (O’Donnell et al. 2000, Walther et al. 2013).  Strain RSA 2353+ was isolated from mouse dung in India in May 1976 (Benny and Benjamin 1993).  The asexual phase of its life cycle is characterized by the production of sporangiophores that bear unispored sporangiola in terminal heads composed of dichotomously branching fertile hyphae (Figs. 1-2).  When crossed with the opposite (-) mating type, this outcrossing heterothallic species produces dark, ornamented zygospores between the opposed suspensors.  Sequencing of the D. robustum RSA 2353 whole genome advances the NSF-funded Zygomycetes Genealogy of Life and 1000 Fungal Genome Projects by providing additional insight into the evolution of nutrient cycling and genome evolution among early diverging fungi.

References:

Benny GL, Benjamin RK. 1993. Observations on Thamnidiaceae (Mucorales). VI. Two new species of Dichotomocladium and the zygospores of D. hesseltinei (Chaetocladiaceae). Mycologia 85:660–671.

O’Donnell K, Lutzoni FM, Ward TJ, Benny GL. 2000. Evolutionary relationships among mucoralean fungi (Zygomycota): Evidence for family polyphyly on a large scale. Mycologia 93:286–296.

Spatafora JW, Chang Y, Benny GL, Lazarus K, Smith ME, Berbee ML, Bonito G, Corradi N, Grigoriev I, Gryganskyi A, James TY, O’Donnell K, Roberson RW, Taylor TN, Uehling J, Vilgalys R, White MM, Stajich JE. 2016. A phylum-level phylogenetic classification of zygomycete fungi based on genome-scale data. Mycologia 108:1028─1046.

Walther G, Pawłowska J, Alastruey-Izquierdo A, Wrzosek M, Rodriguez-Tudela JL, Dolatabadi S, Chakrabarti A, de Hoog GS. 2013. DNA barcoding in Mucorales: an inventory of biodiversity. Persoonia 30:11–47.