Category Archives: ant

Cordyceps on the brain

Cordyceps militaris (Ryan Kepler)I gave a lecture on animal-fungal symbionts and parasites this week so was doing more reading of recent literature on insect-fungi associations. A couple of quick notes worth sharing.

Ophiocordyceps unilateralis was the parasite of the day last week and includes a description of an interesting recent paper looking at the consistency of the symptoms of zombie ants. The article also mentions Carl Zimmer’s post on the same paper in more detail.

You of course have seen the very cool electronic/online Cordyceps monograph at cordyceps.us from Joey Spatafora’s lab?

The genome of Cordyceps militaris was sequenced by researchers at the Chinese Academy of Sciences. They find a reduced copy numbers of many gene families suggesting to the authors that the specialized ecology of the fungus may have limited the need for expanded gene families. The do find expanded copy numbers of metalloproteases – a finding we have also seen in human and amphibian associated pathogens as well as by the authors who looked at the insect associated fungus Metarhizium. There is also a reduction in cutinases and genes related to degrading plant cell walls similar to findings in the human associated pathogens Coccidioides suggesting similar genomic routes to specializing on an animal host from a generalist. They also found that this fungus is heterothallic based on genomic identification of the MAT1-1 locus. There are several more interesting findings in the paper including expression profiling of fruiting body via RNA-Seq.
Zheng, P., Xia, Y., Xiao, G., Xiong, C., Hu, X., Zhang, S., Zheng, H., Huang, Y., Zhou, Y., Wang, S., Zhao, G., Liu, X., St Leger, R., & Wang, C. (2011). Genome sequence of the insect pathogenic fungus Cordyceps militaris, a valued traditional Chinese medicine Genome Biology, 12 (11) DOI: 10.1186/gb-2011-12-11-r116

Tripartate symbioses with fungi

Ants, fungi, and bacteria

I have to admit that I am fascinated by co-evolution of symbiotic and mutalistic systems. A review by Richard Robinson gives an overview. A great example is the mutalism between ants and fungi where the ants cultivate the fungi for food. There are more layers to the relationship as a fungal parasite (Escovopsis) attacks the cultivated fungi, and a bacteria. Several researchers have studied the coevolution of these studies including Ulrich Mueller and Cameron Currie. Currie and Mueller have published several great studies describing the patterns of coevolution and the nature of the cooperation.
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