Saturday, October 22, 2011
Thanks to Nic for congratulating us on the latest Cordyceps-Isaria link. Jen Luangsa-ard did her PhD (with supervision by Rob Samson and myself) looking at the molecular phylogenetics of Paecilomyces sensu lato. As a result, the genus Isaria was 'resurrected' for pathogenic species in the Hypocreales. True Paecilomyces are related to Penicillium and Aspergillus.
But Isaria continues to throw up so many interesting problems. For example, molecular phylogenies show several 'species' (what is a species?) that are currently lumped in to Isaria tenuipes. The same goes for Isaria farinosa and Isaria amoenerosea amongst others. Straight forward morphology of the Isaria's is not helping. Enter the Cordyceps. There are currently very few Cordyceps-Isaria links. However, here in Bhutan we now have two distinct Cordyceps that link to an Isaria that would for now be called Isaria amoenerosea. We have another Cordyceps that links to an Isaria that would be called Isaria farinosa. But this Cordyceps does not match with the traditionally accepted teleomorph of Isaria farinosa – Cordyceps memorabilis. The previously mentioned Cordyceps-Isaria links involved both states on the same specimen. Additionally, several other Cordyceps have been isolated that produce Isaria in culture. And this is only in the last two years in Bhutan!
Rung and I have made significant surveys of insect fungi in Thailand (1989-2009), Japan (2000-2004), Australia (2005-2007) and now Bhutan. Each of these countries is subtly different in terms of the genera that dominate. Bhutan, however, seems to be a haven for Cordyceps-Isaria combinations. Nothing from Bhutan has been sequenced, yet. But in the coming years I am sure that some interesting conclusions will be made about Cordyceps-Isaria – based on the rich material in this tiny Himalayan Kingdom.