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Effects of exogenous GABA on gene expression of Caragana intermedia roots under NaCl stress: regulatory roles for H 2 O 2 and ethylene production
Author(s) -
SHI SHENGQING,
SHI ZHENG,
JIANG ZEPING,
QI LIWANG,
SUN XIAOMEI,
LI CHUNXIU,
LIU JIANFENG,
XIAO WENFA,
ZHANG SHOUGONG
Publication year - 2010
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2009.02065.x
Subject(s) - biochemistry , suppression subtractive hybridization , oxidase test , chemistry , aminooxyacetic acid , reactive oxygen species , gene expression , biosynthesis , amino acid , gene , biology , enzyme , microbiology and biotechnology , cdna library
γ ‐aminobutyric acid (GABA) is a four‐carbon non‐protein amino acid presented in a wide range of organisms. In this study, a suppression subtractive hybridization (SSH) library was constructed using roots of a legume shrub, Caragana intermedia , with the combined treatment of 300 m m NaCl and 300 m m NaCl + 10 m m GABA. We obtained 224 GABA‐regulated unique expressed sequence tags (ESTs) including signal transduction, transcriptional regulation, hormone biosynthesis, reactive oxygen species (ROS) and polyamine metabolism, etc. The key H 2 O 2 ‐generated genes, NADPH oxidase (CaGR60), peroxidase (CaGR61) and amine oxidase (CaGR62), were regulated at the mRNA level by 10 m m GABA, which clearly inhibited H 2 O 2 accumulation brought about by NaCl stress in roots and leaves with the observation of 3,3′‐diaminobenzidine (DAB) staining. Similarly, 10 m m GABA also regulated the expression of 1‐aminocyclopropane‐1‐carboxylic acid (ACC) oxidase (ACO) genes ( Ca GR30 and Ca GR31) and ethylene production in NaCl‐treated roots. Surprisingly, these H 2 O 2 ‐generated genes were enhanced at the mRNA level by a lower concentration of GABA, at 0.25 m m , but not other alternative nitrogen sources, and endogenous GABA accumulated largely just by the application of GABA at either concentration. Our results further proved that GABA, as a signal molecule, participates in regulating the expression of genes in plants under salt stress.