ABSTRACT
During the last two decades, progress on ecological aspects of mycorrhizal fungi has been steady and vivid. Among different approaches, morphotyping has been most frequently utilized to analyze the dynamics of mycorrhizal fungi. Morphotyping relies excessively on sporulation behavior and morphological features. Morphotyping may not always provide accurate judgment regarding the distribution and activity of mycorrhizal fungi. For example, above ground spore patterns discerned might not tally with population, hyphal spread or intensity of activity below ground. Inferences drawn based exclusively on fungal morphotyping could be inaccurate. During the past 5 to 8 years, molecular identification techniques are being increasingly adopted to study the ecological aspects and ascertain inferences put forth previously using morphotyping of mycorrhizal fungi. Advances on molecular ecology of mycorrhizas have been rapid. Molecular analysis of these fungi has also led us to new concepts in plant-microbe interactions. Accordingly, prime focus in this chapter is on molecular approaches relevant to the study of mycorrhizal ecology. A summary of molecular techniques is followed by brief discussions on genetic variation and population genetics. With regard to AM ecology, recent improvements in our knowledge on genetic diversity, spatial and temporal variations, influence on plant diversity above ground and their role in agricultural ecosystems have been discussed in detail. Similarly, for ECM fungi, discussions are confined to their persistence in soil ecosystem, recolonization patterns that develop in disturbed forest plantations, ECM fungal succession in forest stands, nurse functions, mycoheterotrophy, influence of nutrients and microbial interactions.
