Mapping and analysis of a novel candidate Fusarium wilt resistance gene FOC1 in Brassica oleracea |
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| Authors: | Honghao Lv Zhiyuan Fang Limei Yang Yangyong Zhang Qingbiao Wang Yumei Liu Mu Zhuang Yuhong Yang Bingyan Xie Bo Liu Jisheng Liu Jungen Kang Xiaowu Wang |
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| Affiliation: | .Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, 12#Zhongguancun Nandajie Street, Beijing, 100081 China ;.Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Sciences, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (North China), Ministry of Agriculture, 50# Zhanghua Street, Beijing, 100097 China |
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| Abstract: | BackgroundCabbage Fusarium wilt is a major disease worldwide that can cause severe yield loss in cabbage (Brassica olerecea). Although markers linked to the resistance gene FOC1 have been identified, no candidate gene for it has been determined so far. In this study, we report the fine mapping and analysis of a candidate gene for FOC1 using a double haploid (DH) population with 160 lines and a F2 population of 4000 individuals derived from the same parental lines.ResultsWe confirmed that the resistance to Fusarium wilt was controlled by a single dominant gene based on the resistance segregation ratio of the two populations. Using InDel primers designed from whole-genome re-sequencing data for the two parental lines (the resistant inbred-line 99–77 and the highly susceptible line 99–91) and the DH population, we mapped the resistance gene to a 382-kb genomic region on chromosome C06. Using the F2 population, we narrowed the region to an 84-kb interval that harbored ten genes, including four probable resistance genes (R genes): Bol037156, Bol037157, Bol037158 and Bol037161 according to the gene annotations from BRAD, the genomic database for B. oleracea. After correcting the model of the these genes, we re-predicted two R genes in the target region: re-Bol037156 and re-Bol0371578. The latter was excluded after we compared the two genes’ sequences between ten resistant materials and ten susceptible materials. For re-Bol037156, we found high identity among the sequences of the resistant lines, while among the susceptible lines, there were two types of InDels (a 1-bp insertion and a 10-bp deletion), each of which caused a frameshift and terminating mutation in the cDNA sequences. Further sequence analysis of the two InDel loci from 80 lines (40 resistant and 40 susceptible) also showed that all 40 R lines had no InDel mutation while 39 out of 40 S lines matched the two types of loci. Thus re-Bol037156 was identified as a likely candidate gene for FOC1 in cabbage.ConclusionsThis work may lay the foundation for marker-assisted selection as well as for further function analysis of the FOC1 gene. |
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| Keywords: | Brassica oleracea Fusarium wilt Resistance gene FOC1 Map-based cloning |
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