Capacity to control oxidative stress-induced caspase-like activity determines the level of tolerance to salt stress in two contrasting maize genotypes
The response of two maize (Zea mays L.) genotypes, named GR (salt-tolerant) and SK (salt-sensitive), to salt stress (150 mM NaCl) was investigated under controlled environmental growth conditions. Genotype SK experienced more oxidative damage than the GR genotype when subjected to salt stress, which corresponded to higher O2 − production rate and H2O2 content in the SK genotype than the GR genotype. Induction of caspase-like activity in response to salt stress was stronger in the SK genotype than in the GR genotype. On the other hand, induction of antioxidant enzyme activity to scavenge O2 − and H2O2 in response to salt stress was weaker in the SK genotype than in the GR genotype. Consequently, the higher level of oxidative damage in the SK genotype in response to salt stress was manifested as more extensive cell death and biomass reduction in the SK genotype than it was in the GR genotype. Our results suggest that a direct relationship exists between salt stress-induced oxidative damage and cell death-inducing caspase-like activity, with tolerance to the salt stress being controlled by the efficiency of the plant antioxidant enzymes in limiting salt stress-induced oxidative damage and thus limiting cell death-inducing caspase-like activity.
KeywordsAntioxidant enzymes Caspase-like activity Cell death Salt stress Oxidative stress Lipid peroxidation
Analysis of variance
Nicotinamide adenine dinucleotide phosphate
Reactive oxygen species
Sodium dodecyl sulphate
This work was supported by the University of the Western Cape, Stellenbosch University, the National Research Foundation (South Africa) and the National Office for Research and Technology (Hungary).
Conflict of interest
All authors declare that they have no conflict of interest.
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