Development of a novel allele-specific Rfo marker and creation of Ogura CMS fertility-restored interspecific hybrids in Brassica oleracea

Abstract

A novel allele-specific Rfo marker was developed and proved to be effective for MAS of Rfo gene in B. oleracea background and six Ogu-CMS fertility-restored interspecific hybrids were created for the first time. Ogura cytoplasmic male sterility (Ogu-CMS) has been extensively used for Brassica oleracea hybrid production. However, because of maternal inheritance, all the hybrids produced by CMS lines are male sterile and cannot be self-pollinated, which prohibits germplasm maintenance and innovation. This problem can be overcome by using the Ogu-CMS restorer line, but restorer material is absent in B. oleracea crops. Here, Rfo, a fertility-restored gene of Ogu-CMS, was transferred from rapeseed restorer lines into a Chinese kale Ogu-CMS line using interspecific hybridization combined with embryo rescue. Nine interspecific, triploid plant progenies were identified at morphological and ploidy level, with phenotypes intermediate between those of rapeseed and Chinese kale. Because the Rfo marker (Hu et al., Mol Breeding 22:663-674, 2008) cannot distinguish the Rfo and its homologies under a B. oleracea background, a novel allele-specific Rfo marker was developed based on the BLAST analysis of highly homologous Rfo sequences in B. oleracea. Screening using the novel Rfo marker found that six interspecific hybrids carrying Rfo were also fertile, although fertility varied during different flowering periods. Furthermore, BC1 offsprings with the Rfo gene were selected with the allele-specific Rfo marker and showed restored fertility. These results indicated that the novel allele-specific marker could be used for the MAS of Rfo gene in B. oleracea, and this study lays the foundation for the development of Ogu-CMS restorer material in cabbage and its related other subspecies.

Genetic characterization of a new radish introgression line carrying the restorer gene for Ogura CMS in Brassica napus

“…Restorer gene was detected by FISH using C genome and BAC as fish probe while A genome of B. napus was as block (Fig 2c). Green signals were detected consistently in A genome not C genome of B. napus, which is different from previous restorer lines (7,21,23).…”

“…However, not many studies linked this aspect to the radish-derived Ogu CMS in B. napus, the genetic behaviors of Ogu CMS restorer line as pollen donor or accepter remains unclear and is worthy of investigation. Moreover, molecular marker assisted breeding has been applied throughout the breeding history of Ogu-CMS restorer line in Brassica family [11,[21][22][23]. Rfo specific markers in canola were developed by Hu et al [21], while Tian et al [22] and Yu et al [23] applied to B. juncea and B. oleracea respectively, enabling previse selection for low glucosinolate within larger population.…”

The use of genetic, manual and chemical methods to control pollination in vegetable hybrid seed production: a review

“…Extensive research on Ogura cytoplasm has revealed the molecular basis of male sterility and fertility restoration (Bonhomme et al 1992, Tanaka et al 2012, Brown et al 2003, Desloire et al 2003, Koizuka et al 2003, Uyttewaal et al 2008. As a result, genomic data are available for development of molecular markers to assist the selection of CMS and restorer lines (Kim et al 2007, Yu et al 2016.…”

Differentially expressed genes and phenotypic variation in florets among the isogenic Ogura-CMS, DGMS and inbred lines of broccoli

“…The original source of inbred line T54S was derived from the Sakata commercial cultivar (Japan). The broccoli line T54C is derived from the popular Ogura-CMS line (Sakata, Japan) [54,55], and T54M was initially derived from the cabbage line 79-399-3 (our lab) [56,57]. All the plant materials were cultivated and improved by our lab (IVF-CAAS).…”