油萝卜E染色体携带的抗南方根结线虫基因的遗传分析及精细定位

Plant-parasitic nematodes cause yearly great economic loss of agricultural production. Meloidogyne incognita, M.javanica, M.arenaria and M.hapla are the most widespread pathogens which damage to crops.Oil radish(Raphanus sativus L.ssp. oleiferus,2n=18) is usually identified as a variety of cultivating radish. Three types of resistance genes against nematodes were reported in oil radish:Hs1Rph gene resistant to Heterodera schachtii(dominant gene).Gene resistant to Meloidogyne incognita(dominant gene). And genes resistant to M.hapla(they are quantitative trait). In the course of the cooperation between our research group and German scientists,we verified that the Hs1Rph gene was on chromosome D of oil radish.The resistance genes against M.hapla were concerned with oil radish chromosomes A,C and D.Molecular markers were developed total 76 on chromosome E of oil radish.Our results showed recently that selfing line of oil radish A24 were resistant to M.incognita and M.javanica,the chromosome E of oil radish carried the resistance gene.This study will explore the resistant trait against M.arenaria by using 9 disomic rape-radish chromosome addition lines,analyse the resistance level and reveal the relations of three types of resistant trait against 5 pathogenic species of nematodes.It will be determined the chromosome which carry the resistance gene against M.arenaria.At the same time,the genetics of chromosome E and resistance will be analysed from the crossing lines F1 and F2 of rape addition line EE crossed with rape cultivars by using sequence-specific markers detection and resistance test.In further step, the linkage markers with the resistance gene will be screened by means of molecular markers on chromosome E of oil radish and cultivating radish from a constructed F2 population by crossed between A24 and A107(susceptible selfing line). And the resistance gene will be fine mapping on chromosome E.It will provide scientific basis for marker-assisted selection in resistant breeding and the foundation for resistance gene cloning.

植物寄生线虫常造成农业生产极大的经济损失，南方根结线虫、爪哇根结线虫、花生根结线虫和北方根结线虫是危害作物最普遍的病原。油萝卜一般认为是栽培萝卜的变种。据报道油萝卜含3类分别对甜菜胞囊线虫、南方根结线虫和北方根结线虫的抗性基因。项目组与德国合作对油萝卜的研究表明：抗甜菜胞囊线虫基因由D染色体携带；抗北方根结线虫相关基因与其A、C和D染色体有关；在油萝卜E染色体上开发了76个标记；已探明油萝卜自交系A24高抗南方根结线虫和爪哇根结线虫，E染色体携带抗性基因。本项目以E染色体的标记与其携带的抗性基因关联度为切入点，探索油萝卜对花生根结线虫的抗性，揭示其3类基因对5种病原线虫的抗性关系；分析外源的E染色体在油菜杂交后代中遗传特性；用E染色体的相关标记，对构建的抗病与感病自交系之间杂交的F2群体单株进行连锁分析，从而对该基因进行精细定位。为抗病品系分子标记辅助选育提供依据和下一步克隆基因奠定基础。

植物寄生线虫常造成农业生产极大的经济损失，南方根结线虫、爪哇根结线虫、花生根结线虫和北方根结线虫是危害作物最普遍的病原根结线虫。项目利用从德国引进的油萝卜研究其对重要病原线虫的抗性关系，探明油萝卜A24品系含有3个抗线虫的基因分别在不同染色体上；抗性基因不同，所抗的病原种群也不相同。通过探索抗南方根结线虫基因所在染色体遗传行为，油菜附加系EE的花粉经X射线辐射后，其中的ChrE在授粉杂交过程中容易丢失。常规的杂交授粉后，ChrE在F1代中表现出抗性。利用开发的分子标记研究抗根结线虫基因在油萝卜E染色体的精细定位, 发现3个紧密连锁标记OPC01，OPG19和OPN09，4个位点（68.4-700bp, 69.9-681bp, 83.2-629bp和91.6-432bp）与抗性基因密切相关。紧密连锁的分子标记间遗传图距为1.2～2.6cM，OPC01+OPG19的位点68.4-700bp片段与OPC17+OPG19的位点68.9-698bp片段只相距0.5cM。通过利用油萝卜对根结线虫抗性的研究结果，研发的油萝卜绿色秸秆腐解技术与抗病肥料产品已在生产中示范应用，申报发明专利1件，已发表论文2篇。项目研究结果为应用油菜附加系EE培育新品系提供了参考，为有效利用油萝卜品系提供科学依据。