Appearance of male sterile and black radishes in the progeny of cross between <i>Raphanus raphanistrum</i> and <i>Raphanus sativus</i>

Abstract

In addition to Ogura cytoplasmic male sterility (CMS), which is used extensively for F 1 hybrid seed production in Brassicaceae crops, two other CMS systems, NWB CMS and DCGMS, have also been identified. The causal gene for the latter two CMS systems has been identified as a novel chimeric gene, orf463 . We previously reported that orf463 is specific to black radish cultivars and that it is present in line ‘RS-5’ of Raphanus raphanistrum ; however, the orf463 sequence in ‘RS-5’ differed from that of black radish cultivars. Though, R. raphanistrum with an orf463 sequence identical to that found in black radish cultivars was recently identified. We therefore sought to determine whether the orf463 gene in line ‘RS-5’ induces CMS in radishes. We crossed ‘RS-5’ as a female parent with a cultivated radish, ‘Uchiki-Gensuke’, as a male parent, and examined the gross plant morphology and pollen fertility of the resulting progeny. The F 2 population contained both male sterile plants and plants with black roots. The findings showed that R. raphanistrum contains two types of orf463 genes that induce CMS, and that the origin of black radishes could be attributed to R. raphanistrum having orf463 gene.

Re-Sequencing the Mitochondrial Genome Unveils a Novel Isomeric Form of NWB CMS Line in Radish and Functional Verification of Its Candidate Sterile Gene

“…Another coexisting isomeric form was confirmed in YB-A, but it failed to assemble this mitochondrial genome structure successfully [39]. The expression level of the NWB CMS sterility gene orf463a in sterile buds is significantly higher, and sterile plants can be obtained using fertile strains containing the orf463a as the female parent crossed with normal cytoplasm, indirectly proving that orf463a is the candidate gene for sterility in NWB CMS [38][39][40]. However, there is still no direct evidence that the gene causes male infertility.…”

Development and Investigation of HRM Markers to Discriminate Two Ogura Cytoplasmic Male Sterility Restorer Genes in Radish

“…Research on Ogura CMS began in the 1960s, and since then, various researchers have made efforts to elucidate the functions and regulatory mechanisms of these genes in Brassica genus [1,2]. In the case of radish, genes known to induce CMS include mitochondrial orf138 in the case of Ogura CMS [3][4][5], orf125 in Kosena CMS [6,7], apt6 in NWB CMS [8,9], orf463 in DCGMS [10,11], and trnD-trnY genes in DBRMF1, 2 [12]. The Rf gene interacts with Ogura CMS, restoring male fertility and, thereby, enhancing the productivity of CMS plants.…”