ABSTRACT
The nutrient exchange phenomenon between symbionts is a vital aspect of mycorrhizal partnerships. It has attracted the attention of several biologists. Clearer insights about nutrient transfer, particularly P, C, N, and a few other elements were possible mainly through the use of appropriate radiolabels and advanced physiological techniques. During the past five years, there has been a spurt in research activity on molecular aspects of nutrient exchange phenomenon in mycorrhizas. Several ingenious molecular and immuno-cytochemical techniques that allow us to isolate genes, clone them, and understand their localization patterns and regulatory aspects have been utilized. Knowledge about genes and proteins involved in the transport of major nutrients such as C, P and N has greatly improved during the recent past. Emphasis within this chapter is on the recent developments regarding cellular and molecular regulation of nutrient absorption, translocation and exchange within the mycorrhizal systems. Discussions have been confined to three major nutrients namely phosphorus, carbon and nitrogen.
