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Home • Conidiobolus coronatus NRRL28638 v1.0
Photo of Conidiobolus coronatus NRRL28638 v1.0
Figure 1. Single-spored sporangia (sp). The larger sporangium is replicating to produce secondary sporangia ('microconidia'). Arrows point to secondary sporangia; the arrowhead points to the bump-like structure that had everted during discharge of the sporangium. Bar = 5 micrometer. Image is from O'Donnell, K (1979), with permission from the author.

Conidiobolus coronatus (Costantin) Batko is a rare but serious emerging fungal pathogen of humans and other mammals including dogs and horses. C. coronatus can infect the nasal mucosa and from there, the brain. It is exceedingly difficult to treat and can be disfiguring or even deadly. While the protein-degrading enzymes that it secretes may contribute to making it a dangerous pathogen, these same enzymes have possible industrial applications. Because the species is easy to maintain in laboratory culture, it may be possible to exploit its biotechnological potential for the commercial production of proteases and other enzymes.  

A member of fungal order Entomophthorales, or insect destroyers, Conidiobolus coronatus more commonly infects insects such as termites and aphids than mammals and it is also common in soil. It can devastate an insect, growing throughout its body cavity, and then erupting through the exoskeleton to sporulate. It apparently has a tropical distribution or is at least best known from these regions of the World.  Like most species of Entomophthorales, C. coronatus’s asexual sporangia are forcibly discharged. A small, nipple-like structure at the base of the single-spored sporangium (Fig. 1) rapidly everts, sending the sporangium up to 4 cm into the air (Benny, G.L. http://zygomycetes.org/index.php; Lacey 1986). The sporangiophores (stalks producing the sporangia) are phototropic (Page & Humber 1973).  Primary sporangia may either give rise to a secondary sporangium that is also forcibly discharged (Fig. 1), or germinate directly to form a hypha.  Secondary sporangia can either germinate directly to form hyphae or they may give rise to multiple small sporangia that can then germinate.

 

Entomophthorales (Entomophthoromycotina) is one of the major orders of the zygomycetous fungi. The zygomycetous fungi were classified in the phylum Zygomycota, but molecular phylogenetic analyses suggest this phylum is artificial (James et al. 2006).  The relationships among zygomycetous fungi remain unresolved.  Thus, the Entomophthorales represents an important sampling point towards resolving their phylogenetic relationships.  As such, the genome sequence C. coronatus will inform phylogenetic analyses directed at understanding the evolutionary relationships of the Kingdom Fungi, and phylogenomic analyses focused on the evolution of multicelluarity and metabolism among the early diverging Fungi.



Genome Reference(s)

James et al. 2006. Reconstructing the early evolution of Fungi using a six-gene phylogeny.  Nature 443: 818-822.

Lacey J. 1986. Water availability and fungal reproduction: patterns of spore production, liberation and dispersal In: Water, Fungi and Plants (eds. Ayres P.G., Boddy L.), pp. 65-86. Cambridge University Press, Cambridge.

O'Donnell K. 1979. Zygomycetes in Culture. University of Georgia, Athens, Georgia.

Page, R.M. and R.A. Humber.  1973.  Phototropism in Conidiobolus coronatus.  Mycologia 65: 335-364.