title: Dual mechanisms regulating glutamate decarboxylases and accumulation of gamma-aminobutyric acid in tea (Camellia sinensis) leaves exposed to multiple stresses.
abstract: γ-Aminobutyric acid (GABA) is one of the major inhibitory neurotransmitters in the central nervous system. It has multiple positive effects on mammalian physiology and is an important bioactive component of tea (Camellia sinensis). GABA generally occurs at a very low level in plants but GABA content increases substantially after exposure to a range of stresses, especially oxygen-deficiency. During processing of tea leaves, a combination of anoxic stress and mechanical damage are essential for the high accumulation of GABA. This is believed to be initiated by a change in glutamate decarboxylase activity, but the underlying mechanisms are unclear. In the present study we characterized factors regulating the expression and activity of three tea glutamate decarboxylase genes (CsGAD1, 2, and 3), and their encoded enzymes. The results suggests that, unlike the model plant Arabidopsis thaliana, there are dual mechanisms regulating the accumulation of GABA in tea leaves exposed to multiple stresses, including activation of CsGAD1 enzymatic activity by calmodulin upon the onset of the stress and accumulation of high levels of CsGAD2 mRNA induced by a combination of anoxic stress and mechanical damage.
authors.affiliation: Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement &Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou 510650, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Mei
authors.affiliation: Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement &Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou 510650, China.|University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing 100049, China.
authors.forename: Yiyong
authors.initials: Y
authors.lastname: Chen
authors.affiliation: College of Horticultural Science, South China Agricultural University, Wushan Road, Tianhe District, Guangzhou 510642, China.
authors.forename: Lingyun
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement &Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou 510650, China.
authors.forename: Xiumin
authors.initials: X
authors.lastname: Fu
authors.affiliation: Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement &Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou 510650, China.|College of Horticultural Science, South China Agricultural University, Wushan Road, Tianhe District, Guangzhou 510642, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wei
authors.affiliation: Plant &Crop Sciences Division, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK.
authors.forename: Don
authors.initials: D
authors.lastname: Grierson
authors.affiliation: Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement &Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou 510650, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: College of Horticultural Science, South China Agricultural University, Wushan Road, Tianhe District, Guangzhou 510642, China.
authors.forename: Yahui
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Guangdong Food and Drug Vocational College, Longdongbei Road 321, Tianhe District, Guangzhou 510520, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Dong
authors.affiliation: Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement &Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Xingke Road 723, Tianhe District, Guangzhou 510650, China.|University of Chinese Academy of Sciences, No.19A Yuquan Road, Beijing 100049, China.
authors.forename: Ziyin
authors.initials: Z
authors.lastname: Yang
mesh_terms: D000596:Amino Acids / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D028241:Camellia sinensis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D005968:Glutamate Decarboxylase / Q000235:genetics / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D010100:Oxygen / Q000378:metabolism; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013314:Stress, Mechanical; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D007527:Isoenzymes; D010940:Plant Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase; D010100:Oxygen