Transcriptomic Analyses of Chilling Stress Responsiveness in Leaves of Tobacco (Nicotiana tabacum) Seedlings

Low temperature is among the most significant abiotic stresses restricting geographical distribution of plants and reducing crop productivity. However, the molecular regulatory mechanisms of tobacco plants in response to low temperature are poorly understood. To elucidate the molecular mechanisms of chilling tolerance in tobacco, the transcriptomic responses of tobacco under chilling stress were analyzed using RNA-seq analysis. A total of 1675 differentially expressed genes (DEGs) were detected from T12h vs. CK12h and T24h vs. CK24h libraries; among these genes, 1170 genes were upregulated and 505 were downregulated. Additionally, 109 genes were found to be specifically expressed in tobacco seedlings under chilling stress. Functional annotation revealed that the DEGs enriched that categories of regulating soluble sugar and polyamine content and composition to maintain cell osmotic potential, accelerating the de novo synthesis of D1 protein to promote PSII repair, regulating signal transduction such as ABA and GA, and promoting lipid metabolism and lignin synthesis to improve stability of membrane system and mechanical strength of cell wall. This work provides additional insights into the molecular basis of tobacco seedling responses to low-temperature stress.