A phenornics approach to the analysis of the influence of glutathione on leaf area and abiotic stress tolerance in Arabidopsis thaliana

Abstract

Reduced glutathione (GSH) is an abundant low molecular weight plant thiol. It fulfills multiple functions in plantbiology, many of which remain poorly characterized. Aphenomics approach was therefore used to investigate the effects of glutathione home ostasis on growth and stress tolerance in Arabidopsisthalian. Rosette leaf area was compared in mutants that are either defective in GSH synthesis (cad2, pad2, andrax1)or the exportofγ-glutamylcysteine and GSH from the chloroplast (clt) and in wild-type plants understandard growth conditions and following exposure to arange of abiotic stress treatments,including oxidative stress,waterstress,and high salt.In the absence of stress,the GSH synthes is mutants had a significantly lower leaf area than the wild type.Conversely,the clt mutant has a greater leaf area and a significantly reduced lateral rootdensity than the wild type.These findings demonstrate that cellular glutathione homeostasis exerts an influence on root architecture and on rosette area. An impaired capacity to synthesize GSH or a specific depletion of the cytosolic GSH pool did not adversely affect leaf are ainplants exposed to short-termabioticstress. However, the negative effects of long-term exposure to oxidative stress and high salt on leaf are awere less marked in the GSH synthesis mutants than the wild type. These findings demonstrate the importance of cellular glutathione homeostasis in the regulation of plant growth under optimal and stress conditions.