Transcriptome Analysis Revealed Gene Regulatory Network Involved in PEG-induced Drought Stress in Tartary Buckwheat (fagopyrum Tararicum)

Tartary buckwheat is a nutritious pseudo-cereal crop that is resistant to abiotic stresses, such as drought. However, the buckwheat’s mechanisms for responding to drought stress remains unknown. We investigated the changes in physiology and gene expression under drought stress, which was simulated by treatment with polyethylene glycol (PEG). Five physiological indexes, namely MDA content, H2O2 content, CAT activity, SOD activity, and POD activity, were measured over time after 20% PEG treatment. All indexes showed dramatic changes in response to drought stress. A total of 1,190 differentially expressed genes (DEGs) were identified using RNA-seq and the most predominant were related to a number of stress-response genes and late embryogenesis abundant (LEA) proteins. DEGs were gathered into six clusters and were found to be involved in the ABA biosynthesis and signal pathway based on hierarchical clustering and GO and KEGG pathway enrichment. Transcription factors, such as NAC and bZIP, also took part in the response to drought stress. We determined an ABA-dependent and ABA-independent pathway in the regulation of drought stress in Tartary buckwheat. To the best of our knowledge, this is the first transcriptome analysis of drought stress in Tartary buckwheat, and our results provide a comprehensive gene regulatory network of this crop in response to drought stress.