Pires Marcel V, Pereira Júnior Adilson A, Medeiros David B, Daloso Danilo M, Pham Phuong Anh, Barros Kallyne A, Engqvist Martin K M, Florian Alexandra, Krahnert Ina, Maurino Veronica G, Araújo Wagner L, Fernie Alisdair R
Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany.
Max-Planck Partner Group, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-900, Viçosa, Minas Gerais, Brazil.
Plant Cell Environ. 2016 Jun;39(6):1304-19. doi: 10.1111/pce.12682. Epub 2016 Mar 3.
During dark-induced senescence isovaleryl-CoA dehydrogenase (IVDH) and D-2-hydroxyglutarate dehydrogenase (D-2HGDH) act as alternate electron donors to the ubiquinol pool via the electron-transfer flavoprotein/electron-transfer flavoprotein:ubiquinone oxidoreductase (ETF/ETFQO) pathway. However, the role of this pathway in response to other stresses still remains unclear. Here, we demonstrated that this alternative pathway is associated with tolerance to drought in Arabidopsis. In comparison with wild type (WT) and lines overexpressing D-2GHDH, loss-of-function etfqo-1, d2hgdh-2 and ivdh-1 mutants displayed compromised respiration rates and were more sensitive to drought. Our results demonstrated that an operational ETF/ETFQO pathway is associated with plants' ability to withstand drought and to recover growth once water becomes replete. Drought-induced metabolic reprogramming resulted in an increase in tricarboxylic acid (TCA) cycle intermediates and total amino acid levels, as well as decreases in protein, starch and nitrate contents. The enhanced levels of the branched-chain amino acids in loss-of-function mutants appear to be related to their increased utilization as substrates for the TCA cycle under water stress. Our results thus show that mitochondrial metabolism is highly active during drought stress responses and provide support for a role of alternative respiratory pathways within this response.
在黑暗诱导的衰老过程中，异戊酰辅酶A脱氢酶（IVDH）和D-2-羟基戊二酸脱氢酶（D-2HGDH）通过电子传递黄素蛋白/电子传递黄素蛋白：泛醌氧化还原酶（ETF/ETFQO）途径作为泛醇池的替代电子供体。然而，该途径在应对其他胁迫时的作用仍不清楚。在这里，我们证明了这条替代途径与拟南芥对干旱的耐受性有关。与野生型（WT）和过表达D-2GHDH的株系相比，功能缺失的etfqo-1、d2hgdh-2和ivdh-1突变体的呼吸速率受损，对干旱更敏感。我们的结果表明，一个正常运作的ETF/ETFQO途径与植物耐受干旱以及在水分充足时恢复生长的能力有关。干旱诱导的代谢重编程导致三羧酸（TCA）循环中间体和总氨基酸水平增加，以及蛋白质、淀粉和硝酸盐含量降低。功能缺失突变体中支链氨基酸水平的提高似乎与其在水分胁迫下作为TCA循环底物的利用率增加有关。因此，我们的结果表明，线粒体代谢在干旱胁迫反应中高度活跃，并为这种反应中替代呼吸途径的作用提供了支持。
