Comparative physiological, biochemical and proteomic analyses reveal key proteins and crucial regulatory pathways related to drought stress tolerance in faba bean (Vicia faba L.) leaves

Drought is one of the important abiotic factors that affect faba bean growth and productivity in the Mediterranean region. In order to study the response of faba bean plant to water-deficit stress, a physiological and proteomic analysis was carried out in leaf tissue. All physiological parameters were affected by drought. The physiological mechanism underlying the response of faba bean leaves to water-deficit was therefore attributed to the alleviation of oxidative stress via the accumulation of proline and to the synergistic action of the antioxidant enzyme system (CAT, SOD, APX and GPOX). Proteomic analysis identified 2000 proteins from faba bean leaves, of which were 81 differentially expressed. Of those, 36 were downregulated and 45 were upregulated under water-deficit treatment. KEGG and GO enrichments indicated differentially abundant proteins (DAPs) related to photosynthesis, antioxidants and ROS detoxifying enzymes, biosynthesis of amino acids and secondary metabolites, molecular chaperones, signal transduction, energy and carbohydrate metabolism and metabolic enzymes. The current results provide evidence for a complex synergetic pathway, in which ROS detoxification mechanisms and photoprotection constituted the major aspect of water-deficit tolerance in faba bean leaves. These results offer a foundational basis regarding the molecular mechanism involved in drought resistance within the faba bean species.