Overproduction of a rice aldo–keto reductase increases oxidative and heat stress tolerance by malondialdehyde and methylglyoxal detoxification

Abstract

The accumulation of toxic compounds generated by the interaction between reactive oxygen species and polyunsaturated fatty acids of membrane lipids can significantly damage plant cells. A plethora of enzymes act on these reactive carbonyls, reducing their toxicity. Based on the chromosomal localization and on their homology with other stress-induced aldo-keto reductases (AKRs) we have selected three rice AKR genes. The transcription level of OsAKR1 was greatly induced by abscisic acid and various stress treatments; the other two AKR genes tested were moderately stress-inducible. The OsAKR1 recombinant protein exhibited a high nicotinamide adenine dinucleotide phosphate-dependent catalytic activity to reduce toxic aldehydes including glycolysis-derived methylglyoxal (MG) and lipid peroxidation-originated malondialdehyde (MDA). The function of this enzyme in MG detoxification was demonstrated in vivo in E. coli and in transgenic plants overproducing the OsAKR1 protein. Heterologous synthesis of the OsAKR1 enzyme in transgenic tobacco plants resulted in increased tolerance against oxidative stress generated by methylviologen (MV) and improved resistance to high temperature. In these plants lower levels of MDA were detected both following MV and heat treatment due to the activity of the OsAKR1 enzyme. The transgenic tobaccos also exhibited higher AKR activity and accumulated less MG in their leaves than the wild type plants; both in the presence and absence of heat stress. These results support the positive role of OsAKR1 in abiotic stress-related reactive aldehyde detoxification pathways and its use for improvement of stress tolerance in plants.

Expression Analysis of Aldo-Keto Reductase 1 (<i>AKR1</i>) in Foxtail Millet (<i>Setaria italica</i> L.) Subjected to Abiotic Stresses

“…Lipid peroxidation can be estimated as the amount of MDA present in plants as an effect of oxidative damage [18]. Overproduction of OsAKR1 protein in transgenic tobacco plants detected lower levels of MDA and methylglyoxal (MG) in leaf tissues subjected to chemical and heat stress treatments [4]. Based on these observations we can predict the potential role of AKRs in reactive carbonyls detoxification and promoting abiotic stress tolerance as a consequence.…”

“…Overproduction of an alfalfa AKR (MsALR) protein in transgenic tobacco plants improves tolerance against variety of oxidative stress induced by methylviologen (MV), heavy metals (CdCl 2 ), osmotic and long periods of drought [11], cold [12], UV radiation [13] compared to wild type plants. Heterologous overexpression of OsAKR1 in tobacco plants showed better tolerance against heat [4]. Overexpression of Arabidopsis AKR4C9 in transgenic barley showed enhanced freezing tolerance and higher post-frost regenerative capacity [14].…”

“…Prolonged stress conditions contribute to the disruption of balance between the oxidants and antioxidants, causing oxidative stress. Further, the interaction of ROS with several cellular constituents mainly by damaging nucleic acids, oxidizing proteins and causing lipid peroxidation leads to the production of cellular toxic reactive carbonyls such as Acrolein, 4-hydroxynon-2-enol (HNE) and enhance cellular damage in plants [3] [4]. Scavenging of these carbonyl compounds is essential for maintaining the viability of plants.…”

Current trends in genetic manipulations to enhance abiotic and biotic stresses in tobacco

“…Turóczy et al (2011) investigated two mechanisms how overexpression of ARKs in tobacco enhances high temperature tolerance. First, many AKRs are effective in the synthesis of osmolytes, thus having important role in the osmoregulation, which is an important process in plants for the acquisition of desiccation tolerance due to high temperature.…”

Glyoxalase System and Reactive Oxygen Species Detoxification System in Plant Abiotic Stress Response and Tolerance: An Intimate Relationship

“…Overexpression of the ALR gene in tobacco increases tolerance against oxidative agents and low temperature, Cd and drought stress (Oberschall et al, 2000;Hegedüs, 2004). Turóczy et al (2011) reported that transgenic plants overexpressing the OsAKR1 gene showed oxidative stress tolerance induced by methyl viologen (MV) and high temperature. The transgenic plants also exhibited higher AKR activity and accumulated less MG under heat stress conditions.…”