In addition to the nucleus, mitochondria and chloroplasts in plant cells also contain genomes. Efficient DNA repair pathways are crucial in these organelles to fix damage resulting from endogenous and exogenous factors. Plant organellar genomes are complex compared with their animal counterparts, and although several plant-specific mediators of organelle DNA repair have been reported, many regulators remain to be identified. Here, we show that a mitochondrial SWI/SNF (nucleosome remodeling) complex B protein, SWIB5, is capable of associating with mitochondrial DNA (mtDNA) in Arabidopsis thaliana. Gainand loss-of-function mutants provided evidence for a role of SWIB5 in influencing mtDNA architecture and homologous recombination at specific intermediate-sized repeats both under normal and genotoxic conditions. SWIB5 interacts with other mitochondrial SWIB proteins. Gene expression and mutant phenotypic analysis of SWIB5 and SWIB family members suggests a link between organellar genome maintenance and cell proliferation. Taken together, our work presents a protein family that influences mtDNA architecture and homologous recombination in plants and suggests a link between organelle functioning and plant development.
KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: We thank Annick Bleys for help preparing the manuscript. J.B. thanks the Agency for Innovation by Science and Technology in Flanders (IWT-Vlaanderen) for a predoctoral fellowship(projectno.111164)and the European Molecular Biology Organization for a short-term fellowship (project no. ASTF 605-2014). This work was supported by the Interuniversity Attraction Poles Program (IUAP P7/29 ‘MARS’) initiated by the Belgian Science Policy Office, by Ghent University (‘Bijzonder Onderzoeksfonds Methusalem Project’ no. BOF080/01M00408), and the ARC Centre of Excellence in Plant Energy Biology (CE140100008).