Discovery and analysis of effector genes in th eparasitic weed striga asiatica: a multifaceted genomics approach

寄生植物是完全或部分依靠另一种植物生存和繁殖的植物[1]。在非洲，两种寄生植物对谷类作物造成特别严重的损害，它们是草本植物和草本植物。这两种细菌都附着在寄主植物的根上，导致产量大幅下降[2]。抗病品种的开发被视为应对这些寄生虫的战略的重要组成部分，但进展一直受到阻碍，部分原因是缺乏对宿主和寄生虫相互作用的分子遗传学基础的了解[3]。为此，重要的是要更好地了解寄主的抗性和寄生虫的毒力的分子基础。利用基因组学、转录学和生物信息学相结合的方法，在分子水平上比较和分析不同的根生寄生植物毒力基因，以期筛选出可能影响寄生植物毒力的候选基因。效应器是寄生虫分泌的蛋白质，被预测为改变宿主的功能和/或结构，以促进寄生虫的适应[4]。从寄生裤子中发现这种蛋白质将开辟新的研究途径，可能会导致在寄主植物中识别新的抗性基因，这些基因对作物育种者来说可能是无价的。最初，当亚洲链霉菌在特定的水稻品种上生长时，将比较它们的强毒和无毒分离物的基因组是否存在基因。这一初步分析之后将有一条生物信息学管道，该管道将根据来自其他病理系统的已知效应器属性对基因组进行注释，以便生成潜在候选效应器的列表。这份清单将通过整合转录组数据来完善，这些数据将提供寄生虫感染器官(称为吸器)中差异调控基因的信息。将对最有希望的候选基因进行功能分析，以确定：(I)该基因是否在毒力中发挥作用，以及(Ii)如果检测到毒力中的作用，则将进行进一步的分析，以准确地表征其功能。

Parasitic plants are plants that rely entirely or partly on another plant in order to survive and reproduce [1]. In Africa, two parasitic plants causing particularly high levels of damage to cereal crops are Striga hermonthica and Striga asiatica. Both of which attach to the roots of their host plant and cause massive reductions in yield [2]. The development of resistant cultivars is seen as an important part of the strategy to tackle these parasites, but progress has been hampered, in part, by a lack of understanding of the molecular genetic basis of the interaction between the host and parasite [3]. To this end, it is important to better understand the molecular basis of resistance in the host and of virulence in the parasite. The latter is the broad aim of this project.I aim to use a combination of genomics, transcriptomics and bioinformatics to compare and analyze different isolates of the root parasitic plant Striga asiatica at the molecular level, with the goal of selecting candidate genes that may function as effectors for parasite virulence. Effectors are proteins secreted by parasites, which are predicted to modify the function and/or structure of the host in order to facilitate parasite fitness [4]. The discovery of such proteins from parasitic pants would open new avenues of research that would likely lead to the identification of novel resistance genes in host plants that could be invaluable to crop breeders. Initially, the genomes of virulent and avirulent isolates of S. asiatica will be compared for the presence/absence of genes, when growing on particular rice cultivars. This initial analysis will be followed up with a bioinformatics pipeline that will annotate the genomes according to known effector-properties from other pathosystems, in order to generate a list of potential candidate effectors. This list will be refined by integrating transcriptomics data, which will provide information on genes differentially regulated in the infection organ of the parasite (called the haustorium). A selection of the most promising candidates will be functionally analyzed in order to determine; (i) whether the gene plays a role in virulence and (ii) if a role in virulence is detected then further analysis will aim to characterize precisely how it functions.