Arbuscular mycorrhizae in plant survival strategies

Abstract

Mycorrhizae have been associated with vascular plants since the Palaeozoic times. The colonization of terrestrial ecosystems by the ancestors of modern vascular plants was facilitated by symbiotic fungi similar to modern endomycorrhizae. Arbuscular Mycorrhizae (AM) comprise of over 150 species that are not host specific and form symbiotic associations with a wide range of host species. AM bestow a selective advantage on their host over competing non-host species by making available nutrients, providing defence against several pathogenic organisms and by influencing the composition of the microflora of the rhizosphere. However, the benefits that AM provides to its host come with a price tag. The plant has to forego up to 10-20% of its photosynthetic produce to maintain the fungus. This review discusses the conditions under which forming an AM association would be a competitively advantageous strategy for the host plant.