Plant Proteome Responses to Abiotic Stress

Proteomic studies of plant response to abiotic stress include analyses of the effects of water deficit, salt excess, low and high temperatures, high light, and presence of toxic chemicals such as herbicides or heavy metals in the environment. In several instances, proteomics has allowed the identification or novel genes and the characterisation of their regulation and function. In other instances, already known function of proteins found to be regulated by stress have allowed the identification of cellular processes involved in the response. Although many studies have analysed total soluble proteins, only a few have analysed particular subcellular compartments such as chloroplasts or mitochondria. Not only variations in protein abundance but also regulation by post-translational modifications and changes in the subcellular localisation of certain proteins have been observed in response to abiotic stress. Regardless of the species or the environmental conditions studied, some common responses are reported, such as up-regulation of heat shock proteins, stimulation of the antioxidant system or RuBisCO degradation, but it is still difficult to decipher the multiple proteome responses, which vary according to the stress characteristics and to the tissue (differentiation, plant developmental stage). Several studies have shown that the combination of proteomics with metabolomics and genetics may allow a better understanding of integrated plant responses to abiotic stresses. Linking proteome variations to physiological and phenotypic changes will make possible the identification of genes and alleles of interest for the selection of plants able to maintain crop yield as high as possible in unfavourable environments.