The influence of alternative pathways of respiration that utilize branched‐chain amino acids following water shortage in Arabidopsis. (3rd March 2016)

• Record Type: Journal Article
• Authors: 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.
• Is Part Of: Plant, cell and environment. Volume 39:Number 6(2016)
• Page Start: 1304
• Page End: 1319
• Publication Date: 2016-03-03
• Subjects: branched‐chain amino acids -- drought -- ETF/ETFQO pathway -- metabolomics -- respiration -- tricarboxylic acid cycle; Plant physiology -- Periodicals; Plant cells and tissues -- Periodicals; Plant communities -- Periodicals; 581.105
• DOI: 10.1111/pce.12682
• Languages: English
• ISSNs: 0140-7791

Abstract

Abstract: 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. Abstract : The data described in our work present evidence that the ETF/ETFQO pathway play a significant role in drought tolerance mechanism in Arabidopsis thaliana. The results presented here demonstrate the enzymes IVDH and D2HGDH are important for drought tolerance mechanism. Furthermore it provides the first functional clues of a role for ETF/ETFQO pathway under stress conditions other than dark‐induced senescence. Our results thus support recent findings that mitochondrial metabolism is generally highly active during drought tolerance and provides support for a role for alternative respiratory pathways within this response.