Havird 2019 Mitochondrion

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Havird JC, Noe GR, Link L, Torres A, Logan DC, Sloan DB, Chicco AJ (2019) Do angiosperms with highly divergent mitochondrial genomes have altered mitochondrial function? Mitochondrion 49:1-11.

» PMID: 31229574

Havird JC, Noe GR, Link L, Torres A, Logan DC, Sloan DB, Chicco AJ (2019) Mitochondrion

Abstract: Angiosperm mitochondrial (mt) genes are generally slow-evolving, but multiple lineages have undergone dramatic accelerations in rates of nucleotide substitution and extreme changes in mt genome structure. While molecular evolution in these lineages has been investigated, very little is known about their mt function. Some studies have suggested altered respiration in individual taxa, although there are several reasons why mt variation might be neutral in others. Here, we develop a new protocol to characterize respiration in isolated plant mitochondria and apply it to species of Silene with mt genomes that are rapidly evolving, highly fragmented, and exceptionally large (~11 Mbp). This protocol, complemented with traditional measures of plant fitness, cytochrome c oxidase activity assays, and fluorescence microscopy, was also used to characterize inter- and intraspecific variation in mt function. Contributions of the individual "classic" OXPHOS complexes, the alternative oxidase, and external NADH dehydrogenases to overall mt respiratory flux were found to be similar to previously studied angiosperms with more typical mt genomes. Some differences in mt function could be explained by inter- and intraspecific variation. This study suggests that Silene species with peculiar mt genomes still show relatively normal mt respiration. This may be due to strong purifying selection on mt variants, coevolutionary responses in the nucleus, or a combination of both. Future experiments should explore such questions using a comparative framework and investigating other lineages with unusual mitogenomes.

Copyright © 2019 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

Keywords: Alternative NADH dehydrogenase, Cytonuclear interactions, Flux control factor, Mitochondrial respiration, Oroboros Oxygraph 2K, SUIT protocol Bioblast editor: Plangger M O2k-Network Lab: BR Rio de Janeiro Galina A, US CO Fort Collins Chicco AJ


Labels: MiParea: Respiration, mtDNA;mt-genetics 


Organism: Plants 

Preparation: Isolated mitochondria 

Regulation: Flux control, Inhibitor, Substrate  Coupling state: LEAK, OXPHOS  Pathway: N, S, CIV, NS, ROX  HRR: Oxygraph-2k, O2k-Protocol 

Labels, 2019-07