Abstract:
Arbuscular mycorrhizal (AM) fungi, a major component of soil microbial community, forms symbiotic association with the roots of more than 90 percent of terrestrial plants. Arbuscular mycorrhizal colonization has also been reported in hepatics and hornworts. Fossil records indicate that the AM fungi may have played an important role in the success of early terrestrial plants. Arbuscular mycorrhizal fungi play a very important role in the improvement of plant growth. They are vital for the uptake and accumulation of ions from the soil and their translocation to the hosts because of their high metabolic rate and strategically diffuse distribution in the upper layers. Since molecular methods have been used to elucidate the phylogenetic relationships among these fungi, their classification has been in a rapid transition. Molecular field studies have also revealed a large number of putative new species. Presently, the AM fungi are placed in the phylum Glomeromycota, which currently comprises of approximately 150 described species distributed among 10 genera. With the exception of genus Geosiphon, remaining all are exclusively mycorrhizal.
