How abscisic acid collaborates in Brassica napus responses to salt and drought stress: An in silico approach.

Canola (Brassica napus sp.), the most important oily seed product in the world, is affected largely by salinity and drought stresses due to its ability to be planted in arid and semiarid regions. Therefore, studying potent genes involved in salt/drought stress response in canola would help improve abiotic stress tolerance. In this study, genes involved in response to salt and drought stresses in B. napus were investigated via sequence-read archive databases at different time points. The results were analyzed by the GALAXY server to detect DEGs. DEGs associated with short-, medium- and long-term salinity and drought stress were identified via extensive meta-analysis and robust rank aggregation methods. Subsequently, Gene Ontology (GO) analysis of the identified robust DEGs was performed via BLAST2GO. By constructing a protein-protein interaction (PPI) network with Cytoscape software, the hub genes associated with each line of salt and drought stress response were identified. Among all DEGs, HAI2 and DREB1B, which are hub genes, were selected for validation by qRT‒PCR in salt/drought-tolerant and salt/drought-sensitive cultivars of canola, Okapi and RGS, respectively, under salt and drought treatments. Fine-tuning affected the manner and time of contribution of each Abscisic Acid (ABA)-dependent and ABA-independent signaling pathway in response to salinity and drought tolerant and sensitive canola cultivars. Furthermore, the identification of hub genes through meta-analysis provided insight into the molecular responses of canola to salinity/drought stresses and the engineering of abiotic stress tolerance in canola for industrial cultivation of canola in poor-quality lands.