Abstract
Arabidopsis NADPH:2-alkenal α,β-hydrogenase (ALH) detoxifies reactive aldehydes, e.g. 4-hydroxynonenal (HNE), produced from lipid peroxides. Extensive substrate search revealed that ALH recognized other lipid peroxide-derived species such as 4-oxo-nonenal and 9- or 13-keto-octadecadienoic acid. Thus ALH is an universal scavenger for lipid peroxide-derived toxins. Transgenic tobaccos overexpressing the ALH gene (At5g16970) exhibited higher tolerance against photooxidative stress induced by high light (2000 μmol/m2/s, 6 h). This tolerance is attributable to both (i) scavenging of the reactive aldehydes produced via oxidative stress and (ii) dissipation of excessive light in the scavenging reaction.
