The concentration of soluble aluminium (Al) in the soil solution increases at low pH and the prevalence of toxic Al³⁺ cations represent the main factor limiting plant growth on acid soils. Citrate secretion from roots is an important Al-tolerance mechanism in many species including soybean. We isolated mitochondria from the roots of an Al-resistant soybean (Glycine max L.) cv. Jiyu 70 to investigate the relationship between citrate metabolism and Al-induced citrate secretion. Spectrophotometric assays revealed that the activities of mitochondrial malate dehydrogenase and citrate synthase increased and aconitase decreased with increasing of Al concentration (0–50 µM) and duration of Al treatment (30 µM Al, 0.5–9 h). Al-induced citrate secretion was inhibited by the citrate synthase inhibitor suramin, and enhanced by the aconitase inhibitor fluorocitric acid. Mersalyl acid, an inhibitor of a citrate carrier located in mitochondria membrane, also suppressed Al-induced citrate secretion. Transcript level of the mitochondrial citrate synthase gene increased in soybean roots exposed to Al, whereas expression of aconitase showed no significant difference. Expression of Gm-AlCT, a gene showing homology to Al-activated citrate transporters was also induced after 4 h in Al treatment. The Al-dependent changes in activity and expression of these enzymes are consistent with them supporting the sustained release of citrate from soybean roots.

中文翻译：

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勘误：线粒体酶和柠檬酸盐转运蛋白有助于铝诱导大豆根中柠檬酸盐的分泌

在低pH下，土壤溶液中可溶性铝（Al）的浓度会增加，有毒的Al ³⁺阳离子的普及是限制植物在酸性土壤上生长的主要因素。根的柠檬酸盐分泌是许多物种（包括大豆）中重要的耐铝机制。我们从耐铝大豆（Glycine max）的根中分离出线粒体。L.）简历 Jiyu 70研究了柠檬酸盐代谢与铝诱导的柠檬酸盐分泌之间的关系。分光光度法测定表明，线粒体苹果酸脱氢酶和柠檬酸合酶的活性随着铝浓度（0-50 µM）和铝处理时间（30 µM Al，0.5-9 h）的增加而增加，乌头酸酶降低。铝诱导的柠檬酸盐分泌被柠檬酸合酶抑制剂苏拉明抑制，并被乌头酸酶抑制剂氟柠檬酸增强。位于线粒体膜上的柠檬酸盐载体抑制剂巯基酸也抑制了铝诱导的柠檬酸盐分泌。暴露于铝的大豆根中线粒体柠檬酸合酶基因的转录水平升高，而乌头酸酶的表达没有显着差异。Gm的表达-在Al处理4小时后，还诱导出与Al活化的柠檬酸盐转运蛋白同源的AlCT基因。这些酶的活性和表达的铝依赖性变化与它们支持从大豆根中持续释放柠檬酸根一致。