The fertility restorer gene, Rf2, for Lead Rice-type cytoplasmic male sterility of rice encodes a mitochondrial glycine-rich protein.
Cytoplasmic male sterility (CMS) is associated with a mitochondrial mutation that causes an inability to produce fertile pollen. The fertility of CMS plants is restored in the presence of a nuclear-encoded fertility restorer (Rf) gene. In Lead Rice-type CMS, discovered in the indica variety 'Lead Rice', fertility of the CMS plant is restored by the single nuclear-encoded gene Rf2 in a gametophytic manner. We performed map-based cloning of Rf2, and proved that it encodes a protein consisting of 152 amino acids with a glycine-rich domain. Expression of Rf2 mRNA was detected in developing and mature anthers. An RF2-GFP fusion was shown to be targeted to mitochondria. Replacement of isoleucine by threonine at amino acid 78 of the RF2 protein was considered to be the cause of functional loss in the rf2 allele. As Rf2 does not encode a pentatricopeptide repeat protein, unlike a majority of previously identified Rf genes, the data from this study provide new insights into the mechanism for restoring fertility in CMS.
Laboratory of Environmental Plant Biotechnology, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan.
Etsuko
E
Itabashi
Natsuko
N
Iwata
Sota
S
Fujii
Tomohiko
T
Kazama
Kinya
K
Toriyama
D000595:Amino Acid Sequence; D002874:Chromosome Mapping / Q000379:methods; D032461:Chromosomes, Plant; D003001:Cloning, Molecular; D018744:DNA, Plant / Q000235:genetics*; D005298:Fertility / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005816:Genetic Complementation Test / Q000379:methods; D005998:Glycine; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D012275:Oryza / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D030821:Plants, Genetically Modified / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D016415:Sequence Alignment
D018744:DNA, Plant; D024101:Mitochondrial Proteins; D005998:Glycine