Abstract
Glyoxalase pathway involving glyoxalaseI (glyI) and glyoxalaseII (glyII) enzymes is required for glutathione-based detoxification of methylglyoxal (MG), a potent cytotoxic compound. The exact physiological role of the glyoxalase pathway in plants is not well investigated. Our studies have shown that under normal conditions plants maintain and tolerate a certain level of MG, however, under stress conditions MG concentration increases leading to growth inhibition. Overexpression of both the genes in transgenic tobacco and rice showed delayed leaf senescence and improved tolerance to high NaCl, metal and drought stress; the plants were able to grow, flower and set seeds under stress. Enhanced detoxification of MG and maintenance of glutathione homeostasis in the glyoxalase overexpressing transgenic plants is one of the possible mechanisms behind this tolerance. Our preliminary work suggests that MG could also act as a signal molecule for regulating the expression of some of the genes including glyoxalase I and II.
