Seed deterioration during storage is a major problem in agricultural and forestry production and for germplasm conservation. Our previous studies have shown that a mitochondrial outer membrane protein VOLTAGE-DEPENDENT ANION CHANNEL (VDAC) is involved in programmed cell death (PCD)-like viability loss during the controlled deterioration treatment (CDT) of elm (Ulmus pumila L.) seeds, but its underlying mechanism remains unclear. In this study, we demonstrate that the oxidative modification of GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE (GAPDH) is functioned in the gate regulation of VDAC during the CDT of elm seeds. Through biochemical and cytological methods and observations of transgenic material [Arabidopsis (Arabidopsis thaliana), Nicotiana benthamiana, and yeast (Saccharomyces cerevisiae)], we demonstrate that cysteine S-glutathionylated UpGAPDH1 interacts with UpVDAC3 during seed aging, which leads to a mitochondrial permeability transition and aggravation of cell death, as indicated by the leakage of the mitochondrial pro-apoptotic factor cytochrome c and the emergence of apoptotic nucleus. Physiological assays and inductively coupled plasma mass spectrometry (ICP-MS) analysis revealed that GAPDH glutathionylation is mediated by increased glutathione, which might be caused by increases in the concentrations of free metals, especially Zn. Introduction of the Zn-specific chelator TPEN [(N, N, N', N'-Tetrakis (2-pyridylmethyl)ethylenediamine)] significantly delayed seed aging. We conclude that glutathionylated UpGAPDH1 interacts with UpVDAC3 and serves as a pro-apoptotic protein for VDAC-gating regulation and cell death initiation during seed aging.

中文翻译：

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糖酵解酶的谷胱甘肽化促进榆树种子老化过程中的细胞死亡和活力丧失

种子贮藏过程中的变质是农林生产和种质资源保存的主要问题。我们之前的研究表明，线粒体外膜蛋白电压依赖性阴离子通道（VDAC）参与了榆树（Ulmus pumila L.）种子受控恶化处理（CDT）过程中的程序性细胞死亡（PCD）样活力丧失，但其根本机制仍不清楚。在这项研究中，我们证明了甘油醛-3-磷酸脱氢酶 (GAPDH) 的氧化修饰在榆树种子 CDT 过程中 VDAC 的门控调节中发挥作用。通过生化和细胞学方法以及对转基因材料[拟南芥（Arabidopsis thaliana）、烟草本塞姆氏菌（Nicotiana Benthamiana）和酵母（Saccharomyces cerevisiae）]的观察，我们证明半胱氨酸S-谷胱甘肽化UpGAPDH1在种子老化过程中与UpVDAC3相互作用，从而导致线粒体通透性转变线粒体促凋亡因子细胞色素c的渗漏和凋亡细胞核的出现表明细胞死亡加剧。生理测定和电感耦合等离子体质谱 (ICP-MS) 分析表明，GAPDH 谷胱甘肽化是由谷胱甘肽增加介导的，这可能是由于游离金属（尤其是锌）浓度的增加引起的。引入锌特异性螯合剂TPEN [(N,N,N',N'-四(2-吡啶基甲基)乙二胺)]显着延迟了种子老化。我们得出的结论是，谷胱甘肽化的 UpGAPDH1 与 UpVDAC3 相互作用，并作为种子老化过程中 VDAC 门控调节和细胞死亡启动的促凋亡蛋白。