2011•Journal of Agricultural and Food ChemistryRequires access
Accumulation Mechanism of γ-Aminobutyric Acid in Tomatoes (Solanum lycopersicum L.) under Low O 2 with and without CO 2
Nobukazu Mae, Yoshio Makino, Seiichi Oshita, Yoshinori Kawagoe, Atsushi Tanaka, Koh Aoki, Atsushi Kurabayashi, Takashi Akihiro, Kazuhito Akama, Satoshi Koike, M. Takayama, Chiaki Matsukura, Hiroshi Ezura
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Abstract
The storage of ripe tomatoes in low-O(2) conditions with and without CO(2) promotes γ-aminobutyric acid (GABA) accumulation. The activities of glutamate decarboxylase (GAD) and α-ketoglutarate-dependent GABA transaminase (GABA-TK) were higher and lower, respectively, following storage under hypoxic (2.4 or 3.5% O(2)) or adjusted aerobic (11% O(2)) conditions compared to the activities in air for 7 days at 25 °C. GAD activity was consistent with the expression level of mRNA for GAD. The GABA concentration in tomatoes stored under hypoxic conditions and adjusted aerobic conditions was 60-90% higher than that when they are stored in air on the same day. These results demonstrate that upregulation of GAD activity and downregulation of GABA-TK activity cause GABA accumulation in tomatoes stored under low-O(2) conditions. Meanwhile, the effect of CO(2) on GABA accumulation is probably minimal.