Gamma-aminobutyric acid( GABA) is a four-carbon non-protein amino acid conserved from bacteria to plants and vertebrates. Increasing evidence supports a regulatory role for GABA in plant development and the plant'...Gamma-aminobutyric acid( GABA) is a four-carbon non-protein amino acid conserved from bacteria to plants and vertebrates. Increasing evidence supports a regulatory role for GABA in plant development and the plant's response to environmental stress. The biosynthesis of nicotine,the main economically important metabolite in tobacco,is tightly regulated. GABA has not hitherto been reported to function in nicotine biosynthesis. Here we found that water flooding treatment( hypoxia) markedly induced the accumulation of GABA and stimulated nicotine biosynthesis. Suppressing GABA accumulation by treatment with glutamate decarboxylase inhibitor impaired flooding-induced nicotine biosynthesis,while exogenous GABA application directly induced nicotine biosynthesis. Based on these results,we propose that GABA triggers nicotine biosynthesis in tobacco seedlings subjected to flooding. Our results provide insight into the molecular mechanism of nicotine biosynthesis in tobacco plants exposed to environmental stress.展开更多
基金supported by major Science and Technology Program ( 110201101003-TS-03,TS-02-20110014,2011YN02 and 2011YN03)
文摘Gamma-aminobutyric acid( GABA) is a four-carbon non-protein amino acid conserved from bacteria to plants and vertebrates. Increasing evidence supports a regulatory role for GABA in plant development and the plant's response to environmental stress. The biosynthesis of nicotine,the main economically important metabolite in tobacco,is tightly regulated. GABA has not hitherto been reported to function in nicotine biosynthesis. Here we found that water flooding treatment( hypoxia) markedly induced the accumulation of GABA and stimulated nicotine biosynthesis. Suppressing GABA accumulation by treatment with glutamate decarboxylase inhibitor impaired flooding-induced nicotine biosynthesis,while exogenous GABA application directly induced nicotine biosynthesis. Based on these results,we propose that GABA triggers nicotine biosynthesis in tobacco seedlings subjected to flooding. Our results provide insight into the molecular mechanism of nicotine biosynthesis in tobacco plants exposed to environmental stress.
