Oxidative stress tolerance and longevity in Arabidopsis: the late‐flowering mutant gigantea is tolerant to paraquat

Abstract

SummaryRecent genetic analyses of longevity in animals have revealed that long-lived strains are more tolerant to environmental stresses. To investigate whether extended longevity in Arabidopsis also correlates with an increase in stress tolerance, the response was tested of 11 lateflowering mutants to the superoxide radical-generating herbicide paraquat. A tight correlation between flowering time and paraquat tolerance was found when plants were exposed to low doses of herbicide. Furthermore, 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 differed. 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, implying that this phenomenon may be general for all aerobic organisms.

Abiotic stress and the plant circadian clock

“…96 Not only does gi accumulate starch, it also has higher proportions of simple carbohydrates, 97 suggesting that a higher rate of carbon fixation must take place to sustain such a carbohydrate metabolic imbalance. The oxidative-stress resistant phenotype observed by Kurepa et al 99 was partly explained by a constitutive higher expression of ascorbate peroxidase (APX1) and Cd/Zn and Fe superoxide dismutases (CSD2 and FeSOD, respectively). 100 Furthermore, when oxidative stress was created by methylviologen application, gi showed lower increase in H 2 O 2 and superoxide production compared to wild type, 99,101 as well as reduced lipid peroxidation.…”

“…The oxidative-stress resistant phenotype observed by Kurepa et al 99 was partly explained by a constitutive higher expression of ascorbate peroxidase (APX1) and Cd/Zn and Fe superoxide dismutases (CSD2 and FeSOD, respectively). 100 Furthermore, when oxidative stress was created by methylviologen application, gi showed lower increase in H 2 O 2 and superoxide production compared to wild type, 99,101 as well as reduced lipid peroxidation. 100 However in both cases, the mechanism that leads to starch accumulation and oxidative stress resistance in gi is still unknown.…”

“…The GI locus, which encodes for a protein with uncharacterized domains, is involved in rosette development 94 and flowering time, 95 starch metabolism, 96,97 correct circadian clock function, 95,98 and resistance to oxidative stress. 99 While the role of GI in clock control and timing of flower development are starting to emerge, its role in starch accumulation and oxidative stress is still obscure. GI protein is not thought to be an enzyme directly involved in starch metabolism, but the gi mutant was found to display a starch-excess phenotype.…”

Senescence-Associated Gene Expression during Ozone-Induced Leaf Senescence in Arabidopsis1

“…The common mechanism regulating O 3 -induced accelerated leaf senescence and natural leaf senescence may involve reactive oxygen species. Oxidative stress has long been associated with senescence (Thompson et al, 1987), and recently this link was shown in the lateflowering (or extended longevity) Arabidopsis mutant gigantea (gi-3), which exhibited enhanced tolerance to methyl viologen-induced oxidative stress (Kurepa et al, 1998). Following stomatal uptake of O 3 , internal O 3 concentrations rapidly drop (Laisk et al, 1989) as decomposition products, including reactive oxygen species, are formed.…”

TheArabidopsis onset of leaf death5Mutation of Quinolinate Synthase Affects Nicotinamide Adenine Dinucleotide Biosynthesis and Causes Early Ageing

“…In the mid-1950s, it was postulated that reactive oxygen species (ROS) are the main cause of animal ageing, beginning with cumulative damage that results in loss of viability (Harman, 1956). Interestingly, the Arabidopsis longevity mutants oresara1, oresara3, and oresara9 (Woo et al, 2004) and gigantea (Kurepa et al, 1998) all show higher tolerance to oxidative stress. In nonplant species, ROS are mainly produced by mitochondria; however, during leaf senescence in plants, the main ROS source is the chloroplast (Quirino et al, 2000).…”