Opposed sporocladia (spore-producing branches) of Pinnaticoemansia coronantispora. Image provided by Dr. Yousuke Degawa.

Pinnaticoemansia coronantispora is a monotypic and apparently rare fungus in the order Kickxellales (phylum Zoopagomycota). Members of the Kickxellaes are putative saprotrophs that can be isolated from soil and herbivore dung samples (e.g. Coemansia spp.) (Benjamin 1958; Linder 1943). Many Kickxellales species appear to be uncommon because they have only been reported in the literature one or a few times.  Pinnaticoemansia coronantispora was originally described by Kurihara and Degawa (2006) and was isolated from a Japanese soil sample that contained earwig (Dermaptera) dung.  The authors were able to grow the fungus on different media types and identified several unique morphological features, including: 1) paired, opposed sporocladia (spore-producing branches), 2) spores with a sticky, three-lobed corona, and 3) downward, dichotomous hyphal growth after spore germination. An initial phylogenetic analysis placed P. coronantispora in an early-diverging clade within the Kickxellales and sister to another monotypic fungus, Myconymphaea yatsukahoi (Chuang et al. 2017). Interestingly, M. yatsukahoi was also described from Japan and was found growing on a dead insect that had been incubated with a small amount of soil (Kurihara et al. 2001).

One question regarding Kickxellales species is: are they really rare in the environment, or do they appear rare due to undersampling?  The Kickxellales are a relatively understudied group of fungi in a relatively understudied phylum. Therefore, many aspects of the biology, geography, diversity, and evolutionary history of these fungi remain unknown. Genome sequencing is one avenue to explore the biology and evolutionary history of these species. For example, the Kickxellales are closely related to species of Harpellales, which inhabit the guts of arthropods (Tretter et al. 2014). A greater understanding of the evolutionary history of these groups can provide insight into the mechanisms driving the transition between a symbiotic relationship with animals and saprotrophy.  More broadly, soil-borne fungi are potential reservoirs of novel antibiotic and antifungal compounds, as well as other secondary metabolites useful in industrial applications. Genome sequences can help in discovering these genes and uncovering future applications for these fungi.

References:

Benjamin, R.K. 1958. Sexuality in the Kickxellaceae. Aliso 4(1): 149-169.

Chuang, S.-C., Ho, H.-M., Reynolds, N., Smith, M.E., Benny, G.L., Chien, C.-Y., Tsai, J.-L. 2017. Preliminary phylogeny of Coemansia (Kickxellales), with descriptions of four new species from Taiwan. Mycologia 109(5): 815-831.

Kurihara, Y., Degawa, Y. 2006. Pinnaticoemansia, a new genus of Kickxellales, with a revised key to the
genera of Kickxellales. Mycoscience 47: 205–211.

Kurihara, Y., Degawa, Y., Tokumasu, S. 2001. A new genus Myconymphaea (Kickxellales) with peculiar septal plugs. Mycological Research 105(11): 1397-1402.

Linder, D.H. 1943. The genera Kickxella, Martensella, and Coemansia. Farlowia 1(1): 49-77.

Tretter, E.D., Johnson, E.M., Benny, G.L., Lichtwardt, R.W., Wang, Y., Kandel, P., Novak, S.J., Smith, J.F., White, M.M. 2014. An eight-gene molecular phylogeny of the Kickxellomycotina, including the first phylogenetic placement of Asellariales. Mycologia 106(5): 912-935.