香水月季和长尖叶蔷薇MLO基因家族的功能分析与进化机制

由白粉菌引起的白粉病是全球切花月季生产的第一大病害，也是庭院月季和盆花月季的主要病害之一。云南是中国蔷薇属植物的分布中心，也是全球切花月季的主产区之一。但对蔷薇属野生种质资源的抗白粉病性状/基因缺乏研究，进而制约了其在现代月季遗传改良中的应用。MLO基因是一类新型的抗病基因，已有的研究表明，该类基因在一些双子叶植物中具有广谱高抗白粉菌的功能。目前，项目组完成了对香水月季和长尖叶蔷薇MLO家族成员的挖掘和表达分析，初步筛选出3个与抗白粉病相关的候选基因成员。本项目拟对筛选出的候选基因开展参与白粉病抗性的生物学功能分析；对蔷薇属和其他物种的MLO家族基因的结构和功能进行系统的比较分析。本项目以期初步解析该类基因的进化机制及筛选到参与月季—白粉菌互作的家族成员。这不仅可为抗病基因的功能演化提供数据支撑，而且可为月季白粉病抗病性品质改良提供新的思路和基因储备。

Powdery mildew caused by Podosphera pannosa was the most common disease in cut rose production globally. It is also one of the main diseases of garden roses and pot roses. Yunnan is one of the distribution centers of wild Rosa in China, and it is also one of the main cut rose producing areas in the world. However, the unclear resistance mechanism of wild Rosa to powdery mildew and the lack of related resistant genes have been limiting the utilization of wild Rosa in the genetic improvement of modern rose cultivars. Mildew resistance locus o (MLO) genes are new type of disease resistance genes. In dicots such as arabidopsis, pea, and tomato, loss-of-function mutations in MLO genes confer high levels of broad-spectrum resistance in powdery mildew. Recently, the MLO family members from R.longicuspis and R.odorata have been isolated and their expression pattern have been analyzed by us. The results indicated that three MLO gene members of them likely play important roles in Rosa-powdery mildew pathogen interactions. Based on this, we are going to confirm their roles in Rosa-powdery mildew fungus interactions by VIGS and transgenic technologies. Meanwhile, we will systematically compare the structure and function of the MLO family gene in the Rosa and other species. We are looking forward to preliminarily revealed the evolution mechanism of the MLO family gene in plants and find the MLO members which play important roles in Rosa-powdery mildew pathogen interactions. These results will provide us data support for the functional evolution of disease resistance genes. Furthermore, they will provide us new ideas and gene pool for breeding new varieties of powdery mildew resistant rose.