The evolution of the mycorrhizal lifestyles – a genomic perspective
Annegret Kohler, and Francis Martin
28 October 2016, Molecular Mycorrhizal Symbiosis (Ed. Francis Martin) pages 87 – 106; doi: 10.1002/9781118951446
Comparative genomics have provided novel insight in the evolution of the mycorrhizal lifestyle in Glomeromycota and Dikarya. On the basis of the actual genome comparisons relying on 55 genomes of saprotrophic, endophytic and biotrophic species, it appears that the ectomycorrhizal (ECM) symbiosis is as an ancient innovation that developed several times during the course of Mycota evolution, using different sets of non-orthologous symbiosis- related genes, suggesting a convergent evolution on the molecular level of the ECM ecology. The irreversible losses of enzymes involved in the degradation of lignin and crystalline cellulose have played key roles in the evolutionary stability of the arbuscular mycorrhizal (AM) and ECM symbiosis. In contrast to AM and ECM species, the orchid- and ericoid mycorrhizal fungi have a large arsenal of plant cell wall-degrading enzymes (PCWDE), and are able to decay soil organic matter. The mycorrhizal lifestyle is also characterized by a dramatic expansion of species-specific, symbiosis-upregulated orphan genes.
Kohler, A. and Martin, F. (2016) The evolution of the mycorrhizal lifestyles – a genomic perspective, in Molecular Mycorrhizal Symbiosis (ed F. Martin), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9781118951446.ch6