Journal Article

Dissecting the Metabolic Role of Mitochondria during Developmental Leaf Senescence

Gardeström, Per, Keech, Olivier, ANR-11-LABX-0002,ARBRE,Recherches Avancées sur l'Arbre et les Ecosytèmes Forestiers, Law, Simon R, Moritz, Thomas, Dept Plant Physiol ; Umea Plant Science Centre ; Umeå University = Umeå Universitet-Umeå University = Umeå Universitet, Sch Life Sci ; La Trobe University, Szal, Bozena, Dept Forest Genet & Plant Physiol ; Swedish University of Agricultural Sciences = Sveriges lantbruksuniversitet (SLU), Whelan, James, Liebsch, Daniela, Narsai, Reena, Swedish Research Council 621-2014-4688 ; Kempe Foundations ; Carl Tryggers Stiftelse ; French National Research Agency, Investissements d'Avenir program ANR-11-LABX-0002-01, Ziolkowska, Agnieszka, Lindén, Pernilla, Chrobok, Daria, Faculty of Biology [Warsaw] ; Uniwersytet Warszawski [Polska] = University of Warsaw [Poland] = Université de Varsovie [Pologne] (UW), Interactions Arbres-Microorganismes (IAM) ; Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL), Brouwer, Bastiaan, Rouhier, Nicolas

2016

Overview

The functions of mitochondria during leaf senescence, a type of programmed cell death aimed at the massive retrieval of nutrients from the senescing organ to the rest of the plant, remain elusive. Here, combining experimental and analytical approaches, we showed that mitochondrial integrity in Arabidopsis (Arabidopsis thaliana) is conserved until the latest stages of leaf senescence, while their number drops by 30%. Adenylate phosphorylation state assays and mitochondrial respiratory measurements indicated that the leaf energy status also is maintained during this time period.Furthermore, after establishing a curated list of genes coding for products targeted to mitochondria, we analyzed in isolation their transcript profiles, focusing on several key mitochondrial functions, such as the tricarboxylic acid cycle, mitochondrial electron transfer chain, iron-sulfur cluster biosynthesis, transporters, as well as catabolic pathways. In tandem with a metabolomic approach, our data indicated that mitochondrial metabolism was reorganized to support the selective catabolism of both amino acids and fatty acids. Such adjustments would ensure the replenishment of alpha-ketoglutarate and glutamate, which provide the carbon backbones for nitrogen remobilization. Glutamate, being the substrate of the strongly up-regulated cytosolic glutamine synthase, is likely to become a metabolically limiting factor in the latest stages of developmental leaf senescence.Finally, an evolutionary age analysis revealed that, while branched-chain amino acid and proline catabolism are very old mitochondrial functions particularly enriched at the latest stages of leaf senescence, auxin metabolism appears to be rather newly acquired. In summation, our work shows that, during developmental leaf senescence, mitochondria orchestrate catabolic processes by becoming increasingly central energy and metabolic hubs

• Publisher: Oxford University Press ; American Society of Plant Biologists,CCSD,American Society of Plant Biologists
• Subject: Arabidopsis - genetics / Arabidopsis - growth & development / Arabidopsis - metabolism / BIOCHEMISTRY AND METABOLISM / Botanik / Botany / Cell Respiration / Energy Metabolism / FBR Post Harvest Technology / Gene Expression Profiling / Gene Expression Regulation, Plant / Genes, Mitochondrial / Genes, Plant / Life Sciences / Metabolic Networks and Pathways - genetics / Metabolomics / Mitochondria - metabolism / Mitochondria - ultrastructure / Mitochondrial Proteins - metabolism / Plant Leaves - growth & development / Plant Leaves - metabolism / Plant Leaves - ultrastructure / Post Harvest Technology / Transcription, Genetic / Transcriptome - genetics
• ISBN: 0003911734000