黄瓜遗传基础狭窄，种内变异率低，缺乏重要抗性基因，阻碍了其遗传研究与品种改良。发掘利用野生种优异基因，能够突破黄瓜遗传改良瓶颈，同时作为首个完成基因组测序的园艺作物，对其它作物品种改良有重要指导意义。申请者在黄瓜与野生种酸黄瓜种间杂交基础上，创制种间渐渗系，实现了霜霉病等三种抗病基因定位。但定位区域较大、渐渗系基因组物理图谱构建难等问题阻碍了进一步发掘。近年来项目组构建了酸黄瓜BAC文库，与中国农科院蔬菜花卉所合作完成了酸黄瓜全基因组测序，同时在单拷贝基因染色体涂染技术等方面取得突破，为深入发掘抗病基因创造了必要条件。本项目提出基于基因组de novo测序获得紧密连锁的抗病基因分子标记；结合重测序和单拷贝基因染色体涂染作图技术绘制高精度的渐渗系物理图谱；利用遗传转化等技术进行鉴定和分子机理研究。本项目将有力推动栽培黄瓜品种改良进程，保持我国在基于种间杂交的黄瓜遗传与品种改良的特色和优势。

Cucumber is a crop with narrow genetic base and susceptible to many diseases and prone to insect damage for lack of important desease resistant genes. It is necessary to broaden the gene pool of cucumber by introgressing resistance genes from wild relative species to deal with the challenges facing in cucumber production. Besides, as the first sequenced horticultural crop, cucumber becomes an important model crop for gene exploration research..Sour cucumber (C. hystrix Chakr.), being native to China, is the only wild relative species found possessing cross compatibility with cucumber. With the inter-specific introgression lines developed, the the genetic mapping of downy mildew, gummy stem blight and root knot nematode resistant genes were finished. However, the genetic distance between resistant gene locus and linked markers is still far and the high quality genome physical maps of the introgression lines are difficult to construct by using traditional methods. These are big challenges to clone and identify the disease resistant genes. To solve the problems, we have constructed BAC library of sour cucumber and sequenced the wild cucumber genome de novo. We have also developed a chromosome painting method for single-copy gene pools in Cucumis sativus. With those progress newly made, the project proposed herein aim at screening molecular markers that tightly linked with the resistant genes base on the genome sequence data of sour cucumber; accurate assembly of introgression high-resolution physical map by re-sequencing and single-copy gene-based chromosome painting (ScgCP); cloning and functional analysis of resistance genes to downy mildew, gummy stem blight and root knot nematode with plant transformation and VIGS technique. .Expected results could be the breakthrough of cucumber disease-resistant breeding, and therefore maintain our advantage in cucumber inter-specific genetics and cultivar improvement.