Dr Tom Richards and postdoctoral fellow Dr Meredith Jones, previously of the University of Exeter but now in the Department of Zoology, with Dr David Bass (Zoology) have uncovered a 'missing link' in the fungal tree of life after analysing samples taken from the university's pond. Their study, published in Nature, explains the discovery of a hitherto unknown type of fungi which has fundamentally expanded the scientific understanding of this group of organisms.
"This study has been very surprising -- not least because the original sample came from the nearby pond. Fungi have been well studied for 150 years and it was thought we had a good understanding of the major evolutionary groups, but these findings have changed that radically. Current understanding of fungal diversity turns out to be only half the story -- we've discovered this diverse and deep evolutionary branch in fungi that has remained hidden all this time."
The researchers have temporarily named the new group cryptomycota -- which is Greek for 'hidden fungi'. Cryptomycota change the understanding of the whole fungi group because they lack something which was previously considered essential for the classification - a tough cell wall which is important for how fungi feed and grow, breaking down dead animal and plant biomass. Despite lacking the tough cell wall, they seem still to be very successful in the environment because of their extensive diversity and cosmopolitan distribution.
"While the first sample used in our investigation was taken from the university pond, Cryptomycota are present in samples taken from all over the world. The huge genetic diversity and prevalence of this group leads us to believe they probably play an important role in a range of environmental processes. It is possible there are many different forms of this organism with a range of characteristics we don't even know about yet. There is a lot more research to be done to find establish how they feed, reproduce, grow, and their importance in natural ecosystems."
This study is the result of new efforts to try to understand the diversity of life on Earth by taking DNA sampling out into the field. Until recent years, researchers investigating microbial diversity have sampled by growing microbes in lab cultures, but now it seems that the vast majority of life forms are never captured using these methods -- meaning most of the evolutionary complexity of life remains unsampled. This work was primarily supported by an NERC grant to Tom Richards and is a result of an international collaboration between his group and Dr Ramon Massana's group at the Institut de Ciències del Mar, Barcelona.
MDM Jones, I Forn, C Gadelha, MJ Egan, D Bass, R Massana, TM Richards (2011). Discovery of novel intermediate forms redefines the fungal tree of life. Nature doi:10.1038/nature09984