Differential gene expression reveals candidate genes for osmotic stress response in faba bean ( Vicia faba L.) involved in different molecular pathways

Drought and salinity are the most important environmental constraints affecting faba bean ( Vicia faba L.) development and crop yield in Tunisia and other Mediterranean countries. Through using different strategies, associating in silico analysis of gene expression and qRT-PCR, this study aims at identifying key genes of faba bean molecular pathways potentially involved in salt and drought response. The impact of these stresses on several physiological and biochemical parameters were investigated in two genotypes (Bachar and Giza 3). To uncover abiotic stress-related genes and better understand the mechanisms of salt and drought stress tolerance in faba bean, a total of 25 faba bean genes were identified through in silico analysis. These genes were associated with important cellular processes such as transcription regulation, signal transport, kinases, phytohormonal signaling, and defense/stress responses. Most of the studied candidates were expressed at various levels in different organs including leaves, roots, flowers, stems, cotyledons, and seeds suggesting a potential role in the growth and development of faba bean plants. Furthermore, qRT-PCR was used to study gene expression profiles in leaves and roots of Bachar and Giza 3 plants under salt and drought stresses, and ABA treatment. The results showed that selected transcripts were differentially expressed under various treatments in both genotypes suggesting their important roles in abiotic stress tolerance responses. The osmotic-responsive genes identified in this study may be considered as potential candidates with a further application as stress selection markers for the creation of faba bean stress-tolerant varieties in various breeding programs.