Study on Key Components and Molecular Basis Responsible for the Specific Aroma Traits of Flue-cured Tobacco Dabaijin599

The objective of this study was to explore the key aroma component and molecular basis responsible for the specific aroma traits of flue-cured tobacco Dabaijin599, which will lay the foundation for developing flue-cured tobacco varieties with specific aroma traits and industrial utilization of their leaves. Leaf superficial exudates of different tobacco varieties (lines) were detected and smoking evaluation of the corresponding tobacco leaves was conducted to determine the main aroma components contributed to the specific aroma traits of Dabaijin599. Sequence polymorphism analysis of the key genes regulating the aroma component predicted was conducted to explore the molecular mechanism of specific aroma traits of Dabaijin599. The results showed that leaf superficial exudates of flue-cured tobacco Dabaijin599 and Oriental tobacco Samsun contain labdanoid diterpene abienol, while other flue-cured tobacco variety G28 etc. have no labdanoid diterpene abienol. Among the backcross or hybridization population of G28 with Dabaijin599, the offsprings contained abienol present special aroma characteristics like Dabaijin599, however, the ones without abienol had no special aroma characteristics. The 292th base of the key gene NtCPS2 controlling the synthesis of abienol was the wild type G in Dabaijin599 and the mutation type T in common flue-cured tobacco cultivars. Abienol was the key aroma component contributed to specific aroma of flue-cured tobacco variety Dabaijin599. SNP polymorphism in the 292th base of the gene NtCPS2, among Dabaijin599 and other varieties, results in the aroma characteristic difference between Dabaijin599 and the common flue-cured tobacco varieties. Enriching the type and content of aroma components by genetic improvement is an effective way to breed flue-cured tobacco varieties with special aroma.