Abstract：Tobacco aroma sytles is affected by the ecological environment and cultivation conditions. In order to investigate the effect of ecological environment factors on tobacco(Nicotina tabacum L. cv.) aroma style formation, we characterized gene expression profiles in leaf of the tobacco cultivar K326, which were grown in three main growth areas in China: Pingdingshan County in Henan Province, where is famous for producing strong arama feature of tobacco leaf, Yuxi County in Yunnan Province, where displays mild aroma style of tobacco leaf, and Zunyi County in Guizhou Province, where is representative for producing aroma style between strong and mild of tobacco leaf. A total of 920 genes were found to express differently in three ecological zones. After pathway analysised by KEGG(kyoto encyclopedia of genes and genomes), our results showed that carbohydrate metabolism might have more contribution to the formation of different arama styles. While the biosynthesis of phenylpropanoids, biosynthesis of alkaloids and metabolism of terpenoids, which belong to the secondary metabolism, might have great influence on the formation of arama features. Besides, amino acid metabolism might also have a certain influence on aroma features' formation. Also, we found the gene expression of phosphoenolpyruvate carboxylase 1 (PPC1) (photosynthesis related), cell wall invertase 1 (CWINV1) (starch biosynthesis related), 3-hydroxy-3-methylglutaryl coA reductase (HMGR1) and terpene synthase 21 (TPS21) (terpenoids metabolism related), and some genes related to alkaloid biosynthesis were the highest in Henan Province and lowest in Yunnan Province. While the phytoene synthase (PSY) (key enzyme involved in carotenoid biosynthesis) expressed the highest level in Guizhou Province and the lowest in Henan Province. For the carotenoid degradation, the nine-cis-epoxycarotenoid dioxygenase (NCED4) showed the highest level in Yunnan and the lowest in Henan Province. As for the starch metabolism, the α-glucan phosphorylase (PHS1) expressed the highest level in Yunnan and the lowest in Guizhou Province. These results showed that the expression levels of these genes might play important roles in the formation of different aroma styles under the different ecological environments，which can provide some clues for the regulation of the formation of different aroma styles by proper agronomic practices in the future.
