title: Virus-induced gene silencing reveals control of reactive oxygen species accumulation and salt tolerance in tomato by γ-aminobutyric acid metabolic pathway.
abstract: γ-Aminobutyric acid (GABA) accumulates in many plant species in response to environmental stress. However, the physiological function of GABA or its metabolic pathway (GABA shunt) in plants remains largely unclear. Here, the genes, including glutamate decarboxylases (SlGADs), GABA transaminases (SlGABA-Ts) and succinic semialdehyde dehydrogenase (SlSSADH), controlling three steps of the metabolic pathway of GABA, were studied through virus-induced gene silencing approach in tomato. Silencing of SlGADs (GABA biosynthetic genes) and SlGABA-Ts (GABA catabolic genes) led to increased accumulation of reactive oxygen species (ROS) as well as salt sensitivity under 200 mm NaCl treatment. Targeted quantitative analysis of metabolites revealed that GABA decreased and increased in the SlGADs- and SlGABA-Ts-silenced plants, respectively, whereas succinate (the final product of GABA metabolism) decreased in both silenced plants. Contrarily, SlSSADH-silenced plants, also defective in GABA degradation process, showed dwarf phenotype, curled leaves and enhanced accumulation of ROS in normal conditions, suggesting the involvement of a bypath for succinic semialdehyde catabolism to γ-hydroxybutyrate as reported previously in Arabidopsis, were less sensitive to salt stress. These results suggest that GABA shunt is involved in salt tolerance of tomato, probably by affecting the homeostasis of metabolites such as succinate and γ-hydroxybutyrate and subsequent ROS accumulation under salt stress.
authors: Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
authors: Hexigeduleng
authors: H
authors: Bao
authors: Xianyang
authors: X
authors: Chen
authors: Sulian
authors: S
authors: Lv
authors: Ping
authors: P
authors: Jiang
authors: Juanjuan
authors: J
authors: Feng
authors: Pengxiang
authors: P
authors: Fan
authors: Lingling
authors: L
authors: Nie
authors: Yinxin
authors: Y
authors: Li
mesh_terms: D000612:4-Aminobutyrate Transaminase / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D005968:Glutamate Decarboxylase / Q000235:genetics* / Q000378:metabolism; D018551:Solanum lycopersicum / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D053858:Metabolic Networks and Pathways; D018515:Plant Leaves / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D055049:Salt Tolerance; D012965:Sodium Chloride / Q000494:pharmacology; D013312:Stress, Physiological; D050644:Succinate-Semialdehyde Dehydrogenase / Q000235:genetics* / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D017382:Reactive Oxygen Species; D012965:Sodium Chloride; D005680:gamma-Aminobutyric Acid; D050644:Succinate-Semialdehyde Dehydrogenase; D000612:4-Aminobutyrate Transaminase; D005968:Glutamate Decarboxylase
keywords: GABA; ROS; Solanum lycopersicum; TCA cycle; VIGS; abiotic stress; electron transport chain