open access

https://hdl.handle.net/2115/79923

A Lineage-Specific Paralog of Oma1 Evolved into a Gene Family from Which a Suppressor of Male Sterility-Inducing Mitochondria Emerged in Plants

英語

sugar beet

2020-08-27

Oxford University Press

Genome Biology and Evolution

12(12)

2314-2327

Cytoplasmic male sterility (MS) in plants is caused by MS-inducing mitochondria, which have emerged frequently during plant evolution. Nuclear restorer-of-fertility (Rf)genes can suppress their cognateMS-inducing mitochondria.Whereas many Rfs encode a class of RNA-binding protein, the sugar beet (Caryophyllales) Rf encodes a protein resemblingOma1,which is involved in the quality control ofmitochondria. In this study, we investigated the molecular evolution of Oma1 homologs in plants.We analyzed 37 plant genomes and concluded that a single copy is the ancestral state in Caryophyllales. Among the sugar beet Oma1 homologs, the orthologous copy is located in a syntenic region that is preserved in Arabidopsis thaliana. The sugar beet Rf is a complex locus consisting of a smallOma1homolog family (RF-Oma1 family) unique to sugar beet. The gene arrangement in the vicinity of the locus is seen in some but not allCaryophyllalean plants and is absent fromAr. thaliana. This suggests a segmental duplication rather than a whole-genome duplication as themechanism of RF-Oma1 evolution.Of thirty-seven positively selected codons in RF-Oma1, twentysix of these sites are located in predicted transmembrane helices. Phylogenetic network analysis indicated that homologous recombination among the RF-Oma1 members played an important role to generate protein activity related to suppression. Together, our data illustrate how an evolutionarily young Rf has emerged from a lineage-specific paralog. Interestingly, several evolutionary features are sharedwith the RNA-binding protein type Rfs.Hence, the evolution of the sugar beet Rf is representative of Rf evolution in general.

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© The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited.

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