Time-course transcriptomics analysis reveals key responses of populus to salt stress

Salt stress is a ubiquitous abiotic stress in nature and seriously affect woody plants growth and development. To explore how woody plants respond to salt stress, we used RNA-seq technology, time-course transcriptomics analysis, and constructed time-ordered gene co-expression networks (TO-GCNs) to analyze this mechanism using the poplar clone '84 K′ as the research object. Salt stress could increase the relative conductivity and plants damage degree, accumulate reactive oxygen species and malondialdehyde, decrease photosynthesis. In the constructed TO-GCNs, we divided the differentially expressed genes obtained by RNA-seq into six levels corresponding to the processing time points. Subnetworks containing transcription and non-transcription factors in photosynthesis, hyperosmotic salinity response, flavonoid biosynthesis process, abscisic acid (ABA)-activated signaling and cytokinin-activated signaling pathway were constructed, and the potential regulatory relationships between related genes and transcription factors were established. Thus, the potential regulatory mechanisms of transcription factors and response pathways were predicted. The results confirmed the regulation mechanism of woody plants under salt stress and revealed the potential regulatory relationship between transcription factors and response mechanisms in this process.