title: Comprehensive investigation of tobacco leaves during natural early senescence via multi-platform metabolomics analyses.
abstract: Senescence is the final stage of leaf growth and development. Many different physiological activities occur during this process. A comprehensive metabolomics analysis of tobacco middle leaves at 5 different developmental stages was implemented through multi-platform methods based on liquid chromatography, capillary electrophoresis and gas chromatography coupled with mass spectrometry. In total, 412 metabolites were identified, including pigments, sterols, lipids, amino acids, polyamines, sugars and secondary metabolites. Dramatic metabolic changes were observed. Firstly, membrane degradation and chlorophyll down-regulation occurred after the 50% flower bud stage. Levels of major membrane lipids decreased, including those of the glycolipids in chloroplast thylakoids and phospholipids in membrane envelopes. Clear decreases in free sterols and acylated sterol glucosides were detected along with the accumulation of sterol esters. The accumulation of alkaloids was found. The amino acid levels were significantly decreased, particularly those of N-rich amino acids (glutamine and asparagine), thus reflecting N translocation. Subsequently, the antioxidant system was activated. Sugar alcohols and polyphenols accumulated when the lower leaves turned yellow. These results comprehensively revealed the metabolic changes that occur during tobacco leaf development and senescence under natural conditions.
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Lili
authors.initials: L
authors.lastname: Li
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Jieyu
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Yanni
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Lu
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Zhihui
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Chunxia
authors.initials: C
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Guowang
authors.initials: G
authors.lastname: Xu
mesh_terms: D016922:Cellular Senescence / Q000502:physiology*; D008401:Gas Chromatography-Mass Spectrometry; D013058:Mass Spectrometry; D055442:Metabolome; D055432:Metabolomics / Q000379:methods*; D018515:Plant Leaves / Q000254:growth & development / Q000378:metabolism*; D014026:Nicotiana / Q000378:metabolism*