Genetic Linkage Analysis Of PbBa8.1 Locus And FAE1 Gene And Clubroot Resistance-low Erucic Acid Material Selection In Brassica Napus

Rapeseed is one of the most important oil crops in the world,and its production area in China is huge.Clubroot is a worldwide soil-borne disease that causes great harm to rapeseed production.In recent years,it has rapidly spread in China.With the continuous improvement of agricultural mechanization,the spread of clubroot will be even more rapidly and seriously impact the rapeseed industry in China.Cultivating and planting the rapeseed varieties resistant to clubroot is the most effective measure to control the spread of disease,stabilize rapeseed yield,and safeguard industry safety."Hua Shuang 5R"is a variety of Brassica napus resistant to clubroot in our laboratory.It contains a dominant disease resistance locus Pb Ba8.1 derived from the Turnip ECD04.While"Hua Shuang 5R"has a significant effect against clubroot disease,the rapeseeds which use it as a disease-resistant donor are difficult to reduce the erucic acid content to a low erucic acid level,leading to seriously affect the quality of rapeseed oil and hinder the registration of new resistant varieties.Since Pb Ba8.1 is located on the A08 chromosome and the erucic acid synthesis gene FAE1 also has a copy on the A08 chromosome,we speculate that there may be a genetic linkage between them.In this study,the genetic relationship between the Pb Ba8.1 locus and the erucic acid synthesis gene FAE1 was demonstrated,and on this basis,a number of clubroot resistant-low erucic acid（CR-LEA）rapeseed materials were obtained.The specific findings are as follows:1.The FAE1 gene sequence in Huashuang 5R and ECD04 was identical to the high erucic acid sequence from the rapeseed.Both the Pb Ba8.1 locus and the FAE1 gene were located on chromosome A08,and the relative physical distance between them was approximately 700 kb.2.Develop new molecular markers and build physical linkage maps.7 markers were found in the 100 kb around Pb Ba8.1.The physical distances of the flanking markers were17.29 kb,16.19 kb,respectively;8 markers were found within 100 kb of the FAE1,and the physical distances of the flanking markers were 5.38 kb,36.18 kb,respectively.3.Based on the base difference between Pb Ba8.1 and Huashuang 5,using a single nucleotide amplification polymorphic primer design program,the Pb Ba8.1 gene-specific markers Pb1F/R and Pb2F/R were developed.4.F₂ segregating population was constructed from Huashuang 5R,a high erucic acid material containing Pb Ba8.1 and Huashuang 5,a conventional low-erucic acid cultivar.We used half-particle method binding of the specific marker of Pb Ba8.1 and FAE1 to isolate population phenotypes and analyze the genotypes.The Pb Ba8.1 locus was linked to high erucic acid content,and the genetic distance between Pb Ba8.1 and FAE1 was 1.86 c M.5.Use the above-mentioned gene-specific markers to select the self-crossed progeny which elite parents have the Pb Ba8.1-introduced.F₃ population obtained four lines CR-LEA rapeseed.And F₄ population obtained 11 lines altogether 64 individuals CR-LEA rapeseed.F₅ population obtained some high-quality and clubroot resistant-low erucic acid materials.The above results provide theoretical,technical support and germplasm resources for the cultivation of CR-LEA rapeseed.