Transcriptome Analysis Reveals Key Molecular Pathways in Response to Alkaline Salt Stress in Canola (Brassica napus L.) Roots

Soil salinity is a major constraint to crop growth and productivity, limiting sustainable agriculture in arid regions. Understanding the molecular mechanisms underlying salinity tolerance in canola is important for improving salt tolerance and promoting canola cultivation in saline soils. This study exposed canola seedlings to 40 mM Na2CO3 for varying durations before collecting the roots for RNA-Seq analysis and qRT-PCR validation. The results showed that transcript expression in canola roots differed at different stages of Na2CO3 exposure, with oxidative stress responses and sugar metabolism (energy supply) evident after 2 h and increased amino acid metabolism and organic acid metabolism evident after 24 and 72 h. The Na2CO3 treatments increased the expression of numerous differential genes that enrich Ca2+, abscisic acid (ABA), and reactive oxygen species (ROS) signaling pathways. In addition, several transcription factor families associated with Na2CO3 tolerance were identified, including bHLH, WRKY, ERF, MYB, and NAC. In summary, crosstalk between Ca2+ signaling pathways and ABA and ROS signaling pathways induced the expression of downstream genes and produced osmoregulatory substances (organic acids) that further regulate canola tolerance to alkaline salt stress. These results provide a basis for further studies on the regulatory mechanisms of alkaline salt stress adaptation in canola.