Comparative transcriptomic analysis provides insights into the coordinated mechanisms of leaves and roots response to cold stress in Common Vetch

Due to the stronger ability to grow in extreme abiotic stress conditions, common vetch (Vicia sativa L.) has been generally cultivated worldwide and commonly utilized in methane biofuel production and health-promoting foods, and considered as an important protein source to feed livestock and human consumption. Nevertheless, the comprehensive molecular mechanisms on how the aboveground and underground tissues of common vetch response to various abiotic stresses, especially in cold stress, remain largely elusive and unknown. In this study, a total of 30,525 non-redundant full-length transcripts were identified in common vetch, with an average length of 2,291.56 bp and N50 of 3,130 bp. Among these transcripts, 7,689 and 3,415 differentially expressed genes (DEGs) were identified in leaves and roots, respectively, and 1,560 DEGs were induced in both tissues. The Gene Ontology (GO) enrichment results displayed that the DEGs were significantly enriched in the photosynthetic related categories in leaves. Correspondingly, the "response to cold" category was significantly enriched in roots, and most of them were upregulated. The Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment showed that Ca2+, redox, hormonal signalling, circadian clock, and photosynthesis-antenna proteins might play crucial roles through CBF dependent or independent transcriptional pathways to respond cold stress in common vetch. Besides, a total of 36 DEGs involved in ICE-CBF-COR signalling cascade and cold stress were identified. Furthermore, three cold response-related DEGs and three upregulated transcription factors were overexpressed in yeast and indicated their biological functions to confer the tolerance to cold. This work will advance the understanding of common and distinct intrinsic molecular mechanisms beneath the cold response in common vetch leaf and root tissues. The further investigation of the promising potential candidate genes identified in this study will serve as a valuable resource for next step functional genomics research and raise the possibility to improve the cold tolerance through a transgenic approach in common vetch.