基于附加系创制携带萝卜抗根肿病基因的白菜新种质

Clubroot is caused by an obligate parasite, Plasmodiophora brassicae Woron,and is one of the most serious diseases of Chinese cabbage（Brassica rapa ssp. Pekenensis）.The breeding of resistant cultivars is the most effective approach to eliminate the damage caused by clubroot. In Brassica, clubroot-resistance(CR) was found only in European turnip（Brassica rapa ssp. rapifera）, and some CR varieties of Chinese cabbage have been bred by introducing CR genes from European turnip into Chinese cabbage. However, after being released for some years, most of the CR varieties are becoming susceptible to clubroot as a result of genetic variability of the pathogen in some cultivation areas.Therefore, it is important to search for new resources resistant to clubroot, in order to breed new CR cultivars with resistance for longer time. In previous program, we produced a set of disomic Chinese cabbage-radish addition lines by crossing a set of disominc rape-radish addition lines with Chinese cabbage respectively, and in the test of resistance/susceptivity to clubroot, we found each addition line added with individual radish chromosome was susceptible to clubroot,whereas,the donor parent European radish was immune to clubroot, from which it could be inferred that the CR of European radish was interactly expressed by several genes from different chromosomes. To study which chromosomes carry the CR genes, the set of disomic Chinese cabbage-radish addition lines will be crossed with each other in this program, in order to combine different radish chromosomes into one line. By means of radish chromosome specific SSR molecular markers and FISH technology, new Chinese cabbage additional lines added with different radish chromosomes will be developed. And with the help of testing for clubroot resistance on these new additional lines, CR Chinese cabbage-radish addition line(s) will be obtained.

根肿病是由芸薹根肿菌引起的一种土传病害，严重威胁我国白菜生产。培育抗病品种可根本解决其危害。现有抗根肿病白菜品种的抗性基因均来自欧洲芜菁，抗源单一导致抗性不稳定或衰退，迫切需要挖掘新的抗根肿病基因，提高品种的持久抗性。项目申请人利用甘蓝型油菜-萝卜附加系(AACC+RR)为桥梁，构建了整套白菜-萝卜二体附加系(AA+RR)，在抗性鉴定中发现每个附加系均感根肿病，而其外源萝卜供体亲本却对根肿菌免疫，说明该根肿病抗性是由萝卜不同染色体上的多个基因互作控制。本项目拟利用该套二体附加系，通过两两杂交将携带抗根肿病基因的萝卜不同染色体转移到一个附加系中，利用SSR标记和FISH技术，创制白菜-萝卜重组附加系，结合抗性鉴定，筛选抗根肿病的白菜新种质。通过本项研究可以探明与该萝卜根肿病抗性基因表达相关的染色体，并获得我国原创性科研成果—携带萝卜根肿病抗性的白菜新种质，对白菜抗根肿病育种研究具有重要意义。

根肿病是由芸薹根肿菌引起的一种土传病害，严重威胁我国白菜生产。培育抗病品种可根本解决其危害。现有抗根肿病白菜品种的抗性基因均来自欧洲芜菁，抗源单一导致抗性不稳定或衰退，迫切需要挖掘新的抗根肿病基因。本项目通过对整套白菜-萝卜二体附加系进行两两杂交，利用萝卜9个染色体特异的SSR标记对杂交F1进行外源萝卜染色体的鉴定，创制出附加两条萝卜染色体的重组附加系。利用根肿病人工接种抗性鉴定技术，筛选抗根肿病的F1（R1R2）进行性状定向改良。通过自交和回交手段，结合外源萝卜染色体和根肿病抗性的鉴定，以及农艺性状的评价与选择，获得了附加萝卜H和C染色体的抗根肿病的白菜新种质。该种质的获得对白菜抗根肿病的育种研究具有重要意义。