Eprintsev Alexander T, Anokhina Galina B, Selivanova Polina S, Moskvina Polina P, Igamberdiev Abir U
Department of Biochemistry and Cell Physiology, Voronezh State University, Voronezh 394018, Russia.
Department of Biology, Memorial University of Newfoundland, St. John's, NL A1C 5S7, Canada.
Plants (Basel). 2024 Sep 21;13(18):2651. doi: 10.3390/plants13182651.
The effect of salt stress (150 mM NaCl) on the expression of genes, methylation of their promoters, and enzymatic activity of glutamate dehydrogenase (GDH), glutamate decarboxylase (GAD), and the 2-oxoglutarate (2-OG)-dehydrogenase (2-OGDH) complex was studied in maize ( L.). GDH activity increased continuously under salt stress, being 3-fold higher after 24 h. This was accompanied by the appearance of a second isoform with lower electrophoretic mobility. The expression of the gene strongly increased after 6-12 h of incubation, which corresponded to the demethylation of its promoter, while gene expression slightly increased after 2-6 h and then decreased. GAD activity gradually increased in the first 12 h, and then returned to the control level. This corresponded to the increase of expression and its demethylation. Salt stress led to a 2-fold increase in the activity of 2-OGDH during the first 6 h of NaCl treatment, then the activity returned to the control level. Expression of the genes and peaked after 1-2 h of incubation. After 6-8 h with NaCl, the expression of these genes declined below the control levels, which correlated with the higher methylation of their promoters. We conclude that salt stress causes a redirection of the 2-OG flux to the γ-aminobutyric acid shunt via its amination to glutamate, by altering the expression of the and genes, which likely promotes the assembly of the native GDH molecule having a different subunit composition and greater affinity for 2-OG.
研究了盐胁迫（150 mM NaCl）对玉米（L.）中基因表达、其启动子甲基化以及谷氨酸脱氢酶（GDH）、谷氨酸脱羧酶（GAD）和2-氧代戊二酸（2-OG）脱氢酶（2-OGDH）复合体酶活性的影响。在盐胁迫下，GDH活性持续增加，24小时后增加了3倍。这伴随着出现一种电泳迁移率较低的第二种同工型。孵育6 - 12小时后，基因的表达强烈增加，这与其启动子的去甲基化相对应，而基因表达在2 - 6小时后略有增加，然后下降。GAD活性在前12小时逐渐增加，然后恢复到对照水平。这与表达的增加及其去甲基化相对应。在NaCl处理的前6小时，盐胁迫导致2-OGDH活性增加了2倍，然后活性恢复到对照水平。基因和的表达在孵育1 - 2小时后达到峰值。用NaCl处理6 - 8小时后，这些基因的表达下降到对照水平以下，这与其启动子较高的甲基化相关。我们得出结论，盐胁迫通过改变基因和的表达，导致2-OG通量通过其氨基化生成谷氨酸而重定向到γ-氨基丁酸分流，这可能促进具有不同亚基组成且对2-OG具有更高亲和力的天然GDH分子的组装。
