Expression dynamics of glyoxalase genes under high temperature stress in plants

Abstract

Heat stress, owing to the recent climate change events, has emerged as one of the major environmental factors posing a grave threat to plant survival and crop productivity. Oxidative damage due to increased generation of reactive oxygen and dicarbonyl species in response to heat, is one of the serious consequences of high temperature stress. Methylglyoxal (MG), is one such cytotoxic dicarbonyl metabolite whose levels are known to increase in response to high temperature and various other stress conditions in plants. In fact, it is considered as a general consequence of stress in plants. The synergistic co-activation of reactive oxygen species scavenging and the MG detoxification pathways thus, plays a key role in regulation of stress responses for plant acclimation. Glyoxalase enzymes are the major MG detoxifying proteins in the living organisms. In plants, glyoxalases are encoded as multigenic families, known to be involved in plant growth and development, although, chiefly associated with multiple stress inducible behaviour and tolerance. While their role in salinity, drought and heavy metal stresses has been well-studied, their significance under high temperature stress has received limited coverage. In this review, we emphasize on the dynamic role of glyoxalases under high temperature stress for conferring thermotolerance. Through analysis of heat responsive transcriptomes and proteomes of various plants, we provide evidence for a hitherto, unexplored role of glyoxalases as a mechanism of mounting thermotolerance responses. We also, show that ‘priming’ induced stress/cross stress tolerance in plants involves the activation of glyoxalase pathway.