Molecular-genetic marking of Brassica L. species for resistance against various pathogens: achievements and prospects

Cruciferous plants belonging to the genus Brassica of the Cabbage family (Brassicaceae) are cultivated as vegetables, oilseeds and forage crops; they occupy one of the first places in Russia in the gross yield of vegetables. The yield of cabbage crops is adversely affected by various pathogens, including bacterial, viral and fungal infections. The diseases such as black rot of cabbage (caused by the bacterium Xanthomonas campestris pv. campestris), downy mildew (caused by Hyaloperonospora parasitica), Turnip Mosaic Virus (TuMV) are not included in the list of quarantine diseases in the territory of the Russian Federation and Eurasian Economic Union (EAEU), but they can affect a part of the sown area and lead to significant (up to 100 %) crop losses. The development of cultivars resistant to these pathogens is an important trend in Brassica crop breeding in addition to existing methods of agrotechnical and chemical protection. The development of molecular marker techniques and marker-assisted selection (MAS) methods makes it possible to significantly increase the efficiency of breeding resistant cabbage cultivars. The review contains information on the currently known genes and quantitative trait loci (QTLs) associated with resistance to black rot, downy mildew, and TuMV. Molecular mapping data for resistance genes of Brassica species are shown. The molecular markers (RFLP, AFLP, SSR, EST, SNP, InDel, SLAF and others) closely linked to the resistance loci and SCAR-, STS- and dCAPS-markers derived from them for molecular screening are listed. The use of the markers reviewed to assess the Brassica accessions and lines can help the researchers in finding sources and donors of pathogen resistance of cabbage crops