ABSTRACT
Most plant species harbor symbioses with soil microbes in their roots. Mycorrhizal symbiosis plays a major role in ecosystem nutrient cycling, while providing plants with essential nutrients. The most common mycorrhizal symbioses are those with arbuscular mycorrhizal fungi (AMF). The potential of AMF as biofertilizers for the enhancement of crop productivity is well recognized and continues to be exploited (Azcon-Aguilar and Barea, 1997). The AMF are members of the fungal phylum Glomeromycota (Schüssler et al., 2001) and form symbiotic associations with most terrestrial vascular owering plants (Smith and Read, 1997). The abundance of mycorrhizal symbioses suggests their evolutionary success, as evidenced by the evolution of ef cient survival strategies to increase the probability of meeting the host’s roots and by the development of specialized symbiotic structures (reviewed by Harrison, 2005).
