LAUSR

BACKGROUND Volatile organic compounds are critical for food flavor and play important roles in plant-plant interactions and plants' communications with the environment. Tobacco is well-studied for secondary metabolism and most of the typical flavor substances in tobacco leaves are generated at the mature stage of leaf development. However, the changes of volatiles during leaf senescence are rarely studied. RESULTS The volatile composition of tobacco leaves at different stages of senescence was characterized for the first time. Comparative volatile profiling of tobacco leaves at different stages was performed using solid-phase microextraction (SPME) coupled to GC/MS. A total of forty-five volatile compounds were identified and quantified, including terpenoids, GLVs, phenylpropanoids, maillard reaction products, esters, and alkanes. Most of the volatile compounds showed differential accumulation during leaf senescence. Some terpenoids, including neophytadiene, β-springene, and 6-methyl-5-hepten-2-one, increased significantly with the progress of leaf senescence. Hexanal and phenylacetaldehyde also showed increased accumulation in leaves during senescence. Results from gene expression profiling indicated that genes involved in metabolism of terpenoids, phenylpropanoids, and GLVs were differentially expressed during leaf yellowing. CONCLUSION Dynamic changes of volatile compounds during tobacco leaf senescence are observed and the integration of gene-metabolites datasets offered important readouts for the genetic control of volatile production during the process of leaf senescence. This article is protected by copyright. All rights reserved.