Arbuscular mycorrhizal (AM) fungi are the majority of mycorrhizal fungi and are the focus of this section. AM fungi penetrate the cortical cells of roots and form arbuscules (tree-like structures) and vesicles within host plant cells, and their hyphae penetrate into the soil to aid in absorption of nutrients, extending the area of nutrient acquisition. AM spores can be isolated from soil samples containing roots by the wet sieving method, which is widely used and works well with sandy soil samples (Utobo et al.

2011) . Briefly, after soil samples are collected, they are suspended in water (approximately 15-30 ml/g), and mixed vigorously. If spores form in the interior of roots, soil and root samples are blended and the suspension solution is left to settle for a while, and then the supernatant is decanted through standard sieves, which should capture the spores of interest. The procedure should then be repeated, particularly with soil containing large amounts of clay. Spores isolated can be further purified by sucrose centrifugation particularly if the soil is rich in organic debris because it may be difficult to isolate spores hidden in organic matter (Utobo et al. 2011).