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富含γ-氨基丁酸(GABA)的降血压功能水稻正受到越来越多的关注。W025是通过化学诱变和杂交选育而成的水稻新品系,具有巨胚特征,遗传分析表明巨胚基因受单隐性基因控制。进一步研究W025和其原始品种金南风浸水后γ-氨基丁酸(GABA)含量及其合成关键酶———谷氨酸脱羧酶活性的动态,并用半定量RT-PCR检测了2个谷氨酸脱羧酶转录本在浸水过程的表达变化。结果表明,(1)GABA主要集中在胚部,浸水后W025的GABA积累量显著高于金南风。(2)随着浸水时间延长,谷氨酸脱羧酶(GAD)的活性呈逐渐增加趋势,W025胚部的酶活性显著高于金南风。GAD活性的变化与GABA的积累呈显著正相关,表明浸水后种胚GABA的积累与谷氨酸脱羧酶的催化反应有关。(3)2个谷氨酸脱羧酶基因OsGAD1与OsGAD2在W025和金南风之间没有转录水平的差异。提示可能存在其他的谷氨酸脱羧酶基因对浸水后GABA的积累起关键作用。
Hypoglycemic rice enriched with GABA is receiving more and more attention. W025 is a new rice line selected by chemical mutagenesis and cross breeding. It has the characteristics of giant embryo. The genetic analysis indicated that the giant embryo gene is controlled by a single recessive gene. The dynamic changes of γ-aminobutyric acid (GABA) content and glutamate decarboxylase activity of W025 and its original cultivar Kimion after soaking in water were also studied. Two glutamine Changes in acid decarboxylase transcripts during flooding. The results showed that (1) GABA mainly concentrated in the embryo, and the accumulation of GABA in W025 was significantly higher than that in S. aureus after soaking. (2) With prolonged immersion time, the activity of glutamic acid decarboxylase (GAD) showed a gradual increase tendency, and the enzyme activity of W025 embryo was significantly higher than that of S. koraiensis. The change of GAD activity was positively correlated with the accumulation of GABA, indicating that the accumulation of GABA in embryos after immersion was related to the catalytic reaction of glutamate decarboxylase. (3) There was no difference in transcript levels of OsGAD1 and OsGAD2 between the two glutamate decarboxylase genes W025 and S. korean. Suggesting that other glutamate decarboxylase genes may play a key role in the accumulation of GABA after water immersion.