Changes in volatile profile and related gene expression during senescence of tobacco leaves

Abstract

BACKGROUNDVolatile 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 in volatiles during leaf senescence are rarely studied.RESULTSThe 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 coupled with gas chromatography/mass spectrometry. In total, 45 volatile compounds were identified and quantified, including terpenoids, green leaf volatiles (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. The results from gene expression profiling indicated that genes involved in metabolism of terpenoids, phenylpropanoids, and GLVs were differentially expressed during leaf yellowing.CONCLUSIONDynamic changes in volatile compounds during tobacco leaf senescence are observed and the integration of gene‐metabolites datasets offers important readouts for the genetic control of volatile production during the process of leaf senescence. © 2023 Society of Chemical Industry.

Miltiradiene Production by Cytoplasmic Metabolic Engineering in Nicotiana benthamiana

“…In addition, an interesting phenomenon was also observed in our study, which is the accelerated apoptosis in tobacco leaves when SmHMGR was overexpressed alone. Previous studies have shown that the content of terpenoids is highest in the aging stage of tobacco, followed by that of alkanes, and the expression of the HMGR gene is significantly upregulated during aging [61]. Therefore, we hypothesize that the overexpression of SmHMGR might increase the content of apoptosis-related terpenoid compounds, leading to accelerated apoptosis in leaves.…”