南瓜抗白粉病基因的分离及功能鉴定

Cucurbit powdery mildew is one of the major fungal diseases and can cause severe damage to cucurbit crops grown in open fields and greenhouses. Genetic rules of powdery mildew resistance in Cucurbit crops are complex, while the molecular mechanism of cucurbits resistance to powdery mildew is too limited. Therefore, transcriptome databases of inoculated and non-vaccinated pumpkin leaf were sequenced by the second generation of Illumina/Solexa high-throughput sequencing technology. High resistance to host-specific gene fragment is identified after EST analysis and analyzed their function. This research includes: ①Transcriptome is constructed used a highly powdery mildew (PM)-resistant self-cross "112-2" of Cucurbita moschata Duch. as experimental material; ②identify candidate genes of resistance to powdery mildew in pumpkin and clone the above-mentioned candidate genes; ③analysize function of resistant-related genes in transgenic pumpkin after inoculations powdery mildew fungus to seedlings. The aim of this research is to isolate and characterize some candidate genes of resistance to powdery mildew in pumpkin, to further functional analysis of these candidate genes after plants are incubated with powdery mildew. The results would provide the scientific foundation for recognizing the molecular mechanism of interaction between Cucurbita moschata and powdery mildew.

白粉病是严重危害瓜类作物生产的重要真菌病害。瓜类作物白粉病的抗性遗传机制比较复杂，而国内外对瓜类抗白粉病的分子机理研究十分有限。本项目旨在获得高抗白粉病的中国南瓜自交系“112-2”基础上，采用转录组测序筛选出高抗寄主特异表达的基因片段，并进行功能分析。主要内容包括①构建白粉菌侵染的高抗白粉病中国南瓜自交系“112-2”叶片转录组数据库；②筛选和克隆南瓜白粉病的抗病候选基因；③对抗病候选基因通过转基因技术进行白粉菌接种后的功能分析。以上研究将为进一步探明中国南瓜抗白粉病的分子机理奠定基础。

白粉病是严重危害瓜类作物生产的重要真菌病害。本项目旨在获得高抗白粉病的中国南瓜自交系“112-2”基础上，本项目以抗性材料自交系“112-2”和感病材料“九江轿顶”为试材，中国南瓜自交系“112-2”的抗白粉病能力强于“九江轿顶”，与叶绿素含量、气孔密度存在正相关；中国南瓜对白粉病的抗性与白粉菌的生长，光合特征受损和生理生化代谢中的关键酶有关，菌丝生长缓慢，POD和PAL活性的增加有助于“112-2”的抗性增强；自交系“112-2”接种白粉菌24h和48h的转录组分析表明分别分离了3129和3080 DEGs (differentially expressed genes)，对其进行功能注释，抗病材料“112-2”6个DEGs在接菌9h和24h或48h显著上调或下调，与“九江轿顶”接菌处理其表达量明显不同，如bHLH87 (Basic Helix-loop-helix transcription factor), ERF014 (Ethylene response factor), WRKY21 (WRKY domain), HSF (heat stress transcription factor A), MLO3 (Mildew Locus O),和SGT1 (Suppressor of G-Two Allele of Skp1)；unigene (c8328_g1)与甜瓜蛋白SGT1高度同源，采用同源克隆法克隆抗性候选基因CmSGT1, 开放阅读框1080bp。超量表达该基因的转基因烟草对青枯病和疮痂病的抗性明显降低。