Proteomic analysis of roots of two grapevine rootstocks having different tolerance to salt stress

Although grapevine is moderately tolerant to salinity stress, both the environmental climate change and the agricultural management (i.e., salinization due to irrigation practices) could affect in the future the actual production efficiency and fruit quality of this fruit crop. In this framework, the selection of more tolerant grapevine rootstocks is a crucial factor for the development of sustainable agricultural models. To this aim, it is important to improve the knowledge about the molecular, biochemical and physiological bases for the resistance to salinity. Previous studies highlighted that the capability to maintain an adequate root integrity/functionality plays a crucial role in the plant responses to salt stress. The present study was focused on the changes induced by high salt exposure in root proteomes of M4 and 101.14 rootstock genotypes, known to have high and low tolerance to this abiotic stress, respectively. Proteomic analyses were performed by GeLC-MS/MS, a technique by which proteins are initially purified by SDS-PAGE, in-gel digested, and then identified and quantified by mass spectrometry. This approach allowed for both genotypes the identification, with high reliability and good reproducibility, of about 280 proteins. Functional classification was made according to the bin hierarchical tree developed by MapMan ontology. Only proteins showing at least a fold change of 40% in abundance (Student’s t-test, p < 0.05) were considered as significantly changed in abundance. The proteomic analysis revealed different changes in two genotypes that fitted well to the capability of the genotype to respond more (M4) or less (101.14) positively to salt stress condition. Among the more evident differences, the M4 genotype seemed able to sustain the metabolic pathways involved in the synthesis of ATP and NADP(H) as well as to maintain a greater capability of N assimilation and protein synthesis. Differently, the 101.14 genotype showed an increase in some typical enzymes involved in the oxidative stress response, according to a suffering status of the root. Taken together, the data of this proteomic study provide new information about the metabolic changes occurring in the root organ of grapevine plants exposed to high salt concentration, making possible to highlight some of the putative metabolic traits possibly linked to a greater tolerance to this abiotic stress.