Restricted distribution of orf687 as the pollen fertility restorer gene for Ogura male sterility in Japanese wild radish

Abstract

In radish, the mitochondrial gene orf138 found in Ogura cytoplasm is responsible for male sterility, whereas the nuclear restorer gene (Rf gene) inhibits the expression of orf138. To investigate the distribution of the Rf gene for Ogura male sterile cytoplasm in Japanese wild radish, 226 plants collected from 15 regions in Japan and two additional sites of Korea were used as materials. PCR analysis indicated that 42% of the wild radishes possessed orf138. On the other hand, 207 plants (91.6%) were judged to have an Rf gene by the observation of pollen fertility in wild radishes themselves and in hybrids obtained by crosses with a male sterile variety having Ogura cytoplasm. For plants having restorer function, we analyzed the nucleotide sequence of the Rf gene, orf687, identified to date. Among the 207 plants having the Rf gene, 199 amplified the orf687 fragment of the expected size by PCR. PCR products were further analyzed by mismatch-specific endonuclease digestion and PCR-RFLP analysis. As a result, plants that showed an identical RFLP pattern to the known Rf type of orf687 were restricted to 30 plants (14.5% of the 207 plants) collected mainly in populations of southern region of Japan. It was also found that most of the plants (148 plants; 71.5% of 207 plants) possessed the sequence of the orf687 corresponding to the rf genotype lacking the restorer function. We conclude that the Rf gene widely distributed in Japanese wild radish is not orf687.

PPR‐B‐31: a new maintainer allele in the male‐fertility restorer gene of radish (Raphanus sativus) Ogura cytoplasm

“…A similar case was reported by Yasumoto et al. () in Japanese wild radish, and also Wang et al. (), where the restorer line had the same allele ( rfob ) of the PPR‐B gene as the male‐sterile line.…”

“…Yasumoto et al. () compared the predicted protein sequence of the Rf gene (AB326284) derived from a wild Japanese radish to the rf gene (AB326285) from the variety ‘Uchiki‐Gensuke’ and showed that the differences in amino acid sequence can be found in positions 140, 232, 240 and 248. These results may suggest that the N‐terminal region of the protein may have a significant effect on its ability to restore fertility.…”

Molecular characterization of the Rs-Rf 1 gene and molecular marker-assisted development of elite radish (Raphanus sativus L.) CMS lines with a functional marker for fertility restoration

“…Based on the sequence differences between the restorer and non-restorer lines in canola, Hu et al (2008) confirmed that Rfo is located on linkage group N19 the Invader assay and simplesequence repeat analysis. Yasumoto et al (2008a) performed PCR-restriction fragment length polymorphism analysis to investigate the distribution of the Rf gene (orf687) for Ogura male-sterile cytoplasm in Japanese wild radish. The digested PCR product of orf687 was analyzed by agarose gel electrophoresis.…”

“…Further investigation showed that only the digested products obtained with SspI were very distinct in the polyacrylamide gel and that the genotypes of the Rs-Rf 1 and Rs-rf 1 , could be distinguished clearly. For CAPS marker development, PCR products were therefore digested with the SspI restriction enzyme (Yasumoto et al 2008a) according to the manufacturer's instructions. Digested products were separated on a polyacrylamide gel and detected with silver staining for the genotyping of individuals (Liu et al 2003).…”

“…Moreover, to accelerate the process of excellent CMS line development for the production of elite commercial F 1 hybrids in late-bolting radish breeding programs, we isolated the Rs-Rf 1 and its allele, Rs-rf 1 gene in five different restorer lines and maintainers, respectively. The restriction enzyme SspI, which was used by Yasumoto et al (2008a) to investigate the distribution of the Rf gene for Ogura male-sterile cytoplasm in Japanese wild radish, was used to develop a functional marker to identify the candidate maintainer of Chinese late-bolting radish rapidly and accurately in this study. A functional marker-assisted development system for elite CMS lines would greatly facilitate candidate maintainer identification and heterosis utilization in late-bolting radish breeding programs.…”