Format: ORAL

Huaxin Dai1, Mengjiao Ding1, Taibo Liang1, Wang Zhong1, Jinpeng Yang2, Ruiwei Yang2, Baoming Qiao2, Chunlei Yang2and Yanling Zhang1*

1. Zhengzhou Tobacco Research Institute of CNTC, Zhengzhou 450001, China 2. Tobacco Research Institute of Hubei Province, Wuhan 430030, China

Cigar tobacco is sensitive to water stress and can serveas an ideal material for investigating the molecular mechanisms of drought resistance. In this study, we ecamined the response of Cigar tobacco to drought stress through physiological, transcriptomic and metabolic analyses. Cigar tobacco seedlings were subjected to 20 (DR) days of drought stress. Compared to control(CK), the results indicated that drought stress inhibited plant growth, physiological traits and enzyme activities. Transcriptome analysis showed that a total of 6446 differentially expressed genes (DEGs) in DR/CK were identified. These DEGs were found to be involved in tryptophan and -linolenic acid metabolism, flavonoid and phenylpropanoid biosynthesis and the mitogen-activated protein kinase (MAPK) signaling pathway. Furthermore, most alkaloids and lipid content were reduced, amino acids and their derivatives, lignans,flavonoids and coumarins were increased under drought stress. This change can be attributed to the upregulation of type III polyketide synthase B (PKSB), flavonol synthase/flavanone 3-hydroxylase (FLS), and UDP-glycosyltransferases (UGTs), as well as the significant downregulation of R2R3MYB and lipid metabolism-related genes. The regulation of cutin, suberine and wax biosynthesis, the flavonoid pathway and -linolenic acid metabolism contributes to Cigar tobacco s response to drought stress and provides valuable data for understanding the regulatory mechanisms underlying drought tolerance in Cigar tobacco.