Molecular Mechanism of Aluminum Tolerance in Plants: An Overview

Aluminum (Al) is a metal that is abundantly available in the earth's crust in various forms. Though Al has some beneficial role in selected plants, its toxicity and stress symptoms are a matter of concern to agriculturists. Aluminum at high concentration can severely damage a crop by affecting its root system and limiting the uptake of nutrients. As a consequence, the productivity of the plant is diminished. The plant, however, has devised several tolerance mechanisms through which the can combat stress. These mechanisms primarily involve restriction of Al either outside the plant's body or compartmentalization of the metal in a subcellular location thereby limiting its reactivity. A wide array of organic acids are involved in this process, and all are exuded by their transporters. These transporter proteins are synthesized from their respective genes, each of which has several transcription factors. This chapter is an attempt to overview the Al tolerance mechanism of a plant at the molecular level. Efforts have been made to highlight the functions of various transporters involved in the process.