Salicylic acid-mediated alleviation of salt stress: Insights from physiological and transcriptomic analysis in Asarum sieboldii Miq

As global agriculture faces the pressing threat of salt stress, innovative solutions are imperative for sustainable agriculture. The remarkable potential of salicylic acid (SA) in enhancing plant resilience against environmental stressors has recently gained attention. However, the specific molecular mechanisms by which SA mitigates salt stress in Asarum sieboldii Miq., a valuable medicinal plant, remain poorly understood. Here, we evaluated the physiological and transcriptomic regulatory responses of A. sieboldii under salt stress (100 mM NaCl), both in the presence (1 mM SA) and absence of exogenous SA. The results highlighted that SA significantly alleviates salt stress, primarily through enhancing antioxidant activities as evidenced by increased superoxide dismutase, and peroxidase activities. Additionally, we observed an increment in chlorophyll (a and b), proline, total soluble sugar, and plant fresh weight, along with a decrease in malondialdehyde contents. Transcriptome analysis suggested consistency in the regulation of many differentially expressed genes and transcription factors (TFs); however, genes targets (GSTs, TIR1, and NPR1), and TFs (MYB, WRKY, TCP, and bHLH) possessed expressional uniqueness, and majority had significantly up-regulated trends in SA-coupled salt stress treatments. Further, bioinformatics and KEGG enrichment analysis indicated several SA-induced significantly enriched biological pathways. Specifically, plant hormone signal transduction was identified as being populated with key genes distinctive to auxin, cytokinin, ethylene, and salicylic acid signaling, suggesting their important role in salt stress alleviation. Inclusively, this report presents a comprehensive analysis encompassing gene targets, TFs, and biological pathways, and these insights may offer a valuable contribution to our knowledge of SA-mediated regulation and its crucial role in enhancing plant defense against diverse abiotic stressors.