Abstract
In this study, we examined biological effects of malondialdehyde (MDA) formed by polyunsaturated fatty acid peroxidation on protein modification and gene expression in heat stressed plants. In vitro analysis showed that Protein modification by MDA was effectively caused by peroxidation of linolenic acid and was promoted over 33℃ in the presence of reactive oxygen. When intact plants were stressed at 40℃ under light illumination, chloroplast proteins was modified by MDA. To assess the effect of MDA formed during heat stress on gene expression, changes in transcript levels of representative protein family known as heat-shock proteins (HSPs) were investigated. Transcript levels of HSPs increased in correlation with transient increase of MDA in heat stressed Arabidopsis. Furthermore, exogenous MDA increased transcript levels of HSPs in Arabidopsis plants grown under normal condition. In conclusion, MDA might have not only proteotoxic effects but regulatory role in HSP genes expression.
