Natural History Museum
Did the fungi help plants colonize land ?
Nowadays fungi form widespread mutualistic associations with over 90% of plant species, and they are thought to be of key importance to the early development of terrestrial ecosystems. I will present an overview of our current knowledge on early fossil mycorrhizas, and some results of my recent research into the early co-evolution of plants and fungi. The fossil record shows that fungi had entered into a variety of relations with plants during the Devonian Period (ca - 400Ma). They occurred as saprophytes, parasites ormutualistic symbionts. In modern ecosystems the most common and widespread mycorrhizas are the arbuscularmycorrhizas (AM), which are formed by fungi belonging to Glomeromycota. Associations specific to the roots of plants are known from the Upper Carboniferous (ca - 300 Ma). Hereterrestrial ecosystems were well established in forested wetlands. AM are best understood in higher vascular plants, but early fossil plants were evolutionary and structurally closer to extant bryophytes and lycophytes, indicating that comparisonswith the latter are much more appropriate when interpreting the anatomy ofthese early symbioses. My recent work on new endophytes, fungi previouslydescribed both from the 407 million-years-old Rhynie Chert, and fungalcolonization of extant land plants (lycophytes, liverworts and hornworts)reveal several features characteristic of both Mucoromycotina and Glomeromycota. These findings demonstrate that early fungal plant symbioses are more diverse than assumed hitherto, overturning the long held paradigm that the early endophytes were exclusively Glomeromycota.
Host - Prof Alan Gange