title: MutS HOMOLOG1 is a nucleoid protein that alters mitochondrial and plastid properties and plant response to high light.
abstract: Mitochondrial-plastid interdependence within the plant cell is presumed to be essential, but measurable demonstration of this intimate interaction is difficult. At the level of cellular metabolism, several biosynthetic pathways involve both mitochondrial- and plastid-localized steps. However, at an environmental response level, it is not clear how the two organelles intersect in programmed cellular responses. Here, we provide evidence, using genetic perturbation of the MutS Homolog1 (MSH1) nuclear gene in five plant species, that MSH1 functions within the mitochondrion and plastid to influence organellar genome behavior and plant growth patterns. The mitochondrial form of the protein participates in DNA recombination surveillance, with disruption of the gene resulting in enhanced mitochondrial genome recombination at numerous repeated sequences. The plastid-localized form of the protein interacts with the plastid genome and influences genome stability and plastid development, with its disruption leading to variegation of the plant. These developmental changes include altered patterns of nuclear gene expression. Consistency of plastid and mitochondrial response across both monocot and dicot species indicate that the dual-functioning nature of MSH1 is well conserved. Variegated tissues show changes in redox status together with enhanced plant survival and reproduction under photooxidative light conditions, evidence that the plastid changes triggered in this study comprise an adaptive response to naturally occurring light stress.
authors.affiliation: Center for Plant Science Inovation, University of Nebraska, Lincoln, Nebraska 68588-0660, USA.
authors.forename: Ying-Zhi
authors.initials: YZ
authors.lastname: Xu
authors.forename: Maria P
authors.initials: MP
authors.lastname: Arrieta-Montiel
authors.forename: Kamaldeep S
authors.initials: KS
authors.lastname: Virdi
authors.forename: Wilson B M
authors.initials: WB
authors.lastname: de Paula
authors.forename: Joshua R
authors.initials: JR
authors.lastname: Widhalm
authors.forename: Gilles J
authors.initials: GJ
authors.lastname: Basset
authors.forename: Jaime I
authors.initials: JI
authors.lastname: Davila
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Elthon
authors.forename: Christian G
authors.initials: CG
authors.lastname: Elowsky
authors.forename: Shirley J
authors.initials: SJ
authors.lastname: Sato
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Clemente
authors.forename: Sally A
authors.initials: SA
authors.lastname: Mackenzie
mesh_terms: D029681:Arabidopsis Proteins / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism*; D018744:DNA, Plant / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D054628:Genome, Chloroplast; D054629:Genome, Mitochondrial; D042822:Genomic Instability; D008027:Light; D019684:Magnoliopsida / Q000235:genetics / Q000502:physiology / Q000528:radiation effects*; D008928:Mitochondria / Q000378:metabolism*; D051719:MutS DNA Mismatch-Binding Protein / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D018515:Plant Leaves / Q000235:genetics / Q000502:physiology; D030821:Plants, Genetically Modified / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D011809:Quinones / Q000032:analysis; D011995:Recombination, Genetic
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D011809:Quinones; C523213:MSH1 protein, Arabidopsis; D051719:MutS DNA Mismatch-Binding Protein