OXIDATIVE STRESS TOLERANCE AND LONGEVITY IN ARABIDOPSIS - THE LATE-FLOWERING MUTANT GIGANTEA IS TOLERANT TO PARAQUAT

Recent genetic analyses of longevity in animals have revealed that lon g-lived strains are more tolerant to environmental stresses. To invest igate whether extended longevity in Arabidopsis also correlates with a n increase in stress tolerance, the response was tested of 11 late-flo wering mutants to the superoxide radical-generating herbicide paraquat . A tight correlation between flowering time and paraquat tolerance wa s found when plants were exposed to low doses of herbicide. Furthermor e, the mutant gigantea (gi-3) with the longest delay in flowering time had a high tolerance level to paraquat-induced oxidative stress. All the tested gi alleles had an increased tolerance to paraquat toxicity compared to wild-type, although the actual levels of tolerance differe d. In addition, the gi-3 mutant was more tolerant to hydrogen peroxide . These results suggest that the link between longevity and oxidative stress resistance in plants is similar to that found in animals, imply ing that this phenomenon may be general for all aerobic organisms.