Abstract:

In order to understand the effects of drought stress with different concentrations of PEG6000 on metabolites and metabolic pathway of Panax notoginseng leaves, one-year-old Panax notoginseng were treated by natural drought (CK), 2.5% PEG6000 (HE), 5% PEG6000 (HM), and 7.5% PEG6000 (HK). The metabolites of Panax notoginseng leaves treated in different methods were measured by using liquid chromatography-mass spectrometry (LC-MS) technology. The results showed that the metabolites of amino acids, glycerides, fatty acyl, nucleotides, lactones, organic acids, ketones and lipids were significantly up-regulated in expression under drought stress by 2.5% PEG 6000, and were significantly enriched in metabolic pathways such as glycerophosphate metabolism, α-linolenic acid metabolism, nerve sheath lipid metabolism and polyketide unit biosynthesis. After drought stress by 5% PEG6000, the metabolites of alkaloids, amino acids, glycerophosphates, benzenes, lipids and heterocyclic compounds were significantly up-regulated in expression, and were significantly enriched in metabolic pathways such as linoleic acid metabolism, carotenoid biosynthesis, nucleotide metabolism, and zeatin biosynthesis. After drought stress by 7.5% PEG6000, the metabolites of flavonoids, glycerophosphates, lipids and heterocyclic compounds were significantly up-expressed in expression, and were significantly enriched in metabolic pathways such as secondary metabolites biosynthesis, porphyrin metabolism, riboflavin metabolism and β-alanine metabolism. The metabolites of Panax notoginseng leaves existed some differences under drought stress with different concentrations of PEG6000, and they responded to drought stress through different metabolic pathways, thus to improve their ability of drought resistance.

Key words: Panax notoginseng, PEG6000, drought stress, liquid chromatography-mass spectrometry, metabolomic, metabolite