Abstract:

Cytoplasmic male sterility (CMS) has been widely used as an efficient pollination control system in rapeseed (Brassica napus) hybrid production. With the exploitation of wild species of Crucifer and the application of biotechnology, several cytoplasmic male sterile systems of oilseed rape have been reported in recent years. Traditional methods used for the identification of cytoplasm, however, are time and labor consuming with low efficiency. Thus, it is highly desirable to develop an efficient and accurate identification method for cytoplasm classification. Repetitive sequence based polymerase chain reaction (rep-PCR) has proved to be a good method for the identification of mitochondrial and procaryotic organisms which contain abundant repetitive sequences in genome. Fingerprints of six cytoplasmic male sterility materials including Nsa, Pol, nap, No, Ogu, and Ath were mapped using rep-PCR. Based on the PCR amplification band patterns by two primer pairs, six male sterile cytoplasms in rapeseed could be distinguished unambiguously. Two bands, ERIC750 and ERIC4000, were unique to NSa CMS which was derived from somatic hybrids between B. napus and S. arvensis. The PCR results using gene specific primers also showed that NSa is a novel cytoplasmic male sterility system in oilseed rape. Thus, a method for cytoplasm classification in oilseed rape was established. The two specific markers for NSa cytoplasm not only confirmed the distinctness of NSa cytoplasm from other male sterile cytoplasm at molecular level, but also provided useful tools for the protection of intellectual property right of this potential CMS material in rapeseed breeding and production.

Key words: Oilseed rape, Alloplasmic male sterility, Molecular characterization, rep-PCR