Functional Analysis Of The Cabbage Fusarium Wilt Resistance Gene FOC1 And Rapid Generation Of The Resistant Line

Cabbage(Brassica oleracea var.capitata L.)is one of the most important vegetable crops widely cultivated in the world.Cabbage Fusarium Wilt(CFW)is a typical soil borne disease,seriously affecting the yield and quality of cabbage,and is difficult to be controlled through traditional measures such as chemicals.Breeding CFW-resistant varieties is the most effective strategy to alleviate CFW threatening.In this study,we transforms FOC1 gene into CFW-susceptible cabbage inbred lines by agrobacterium mediated method to verify the function of the FOC1 gene.The characteristics of the target protein was determined by subcellular localization experiment,and the composition,structure,biological function and biological pathway of the target protein was predicted using bioinformatics software.These results lay the theories foundation for elucidating the resistance mechanism of FOC1.We also performed the introgression of FOC1 into an elite cabbage line 01-20 through the combined application of a microspore culture,genome background analysis and disease resistance-specific marker assisted selection,in order to obtain an elite cabbage breeding materials with Fusarium wilt resistance.The results are as follows:1? To perform genetic transformation,11 cabbage inbred lines highly susceptible to Fusarium wilt were screened,among which XW inbred line was the best material for genetic transformation with the lowest browning rate and the highest differentiation budding rate.The Fusarium wilt resistance gene FOC1 was transformed into the cabbage inbred line XW via agrobacterium mediated method.Six plants with hygromycin resistance were obtained.Four of them were vertified by PCR test,and the expression of FOC1 gene was significantly higher;and the 4 positive plants had no Fusarium wilt symptoms through artificial inoculation.Thus,the function of FOC1 gene was preliminary validated.2? The protein encoded by FOC1 gene was localized in nucleus by subcellular localization experiment.Through bioinformatics analysis,the target protein of FOC1 is a hydrophilic protein,with no transmembrane domain and signal peptide recognition site,but many random coil structures in the protein secondary structure.It is a typical TIR-NBS-LRR resistance protein that may be involved in the signal transduction pathway,and regulates protein binding and ADP binding.3? 24 markers were selected for background analysis based on resequencing data of 96-100(HR)and 01-20(HS).A simple sequence repeat marker Frg13 closely linked with FOC1 with high universality was developed for foreground selections.The DH line D134 was used as the CFW-resistance source material.FOC1 was rapidly transferred to 01-20 plants,combining foreground and background selection,created the resistant introgression line YR01-20,which significantly improved the breeding efficiency,and provided an elite breeding material for cabbage Fusarium wilt resistance breeding.