Shifts in plant gene expression and corresponding phloem sap components during trilateral interaction of barley (Hordeum vulgare), aphid species (Rhopalosiphum padi) and the aphid-transmitted Barley Yellow Dwarf Virus (BYDV)

描述了由大麦黄矮病(BYDV)传播的黄矮病病毒及其与大麦黄矮病的相互作用。在开发成功的防治黄矮病的策略之前，必须研究这种三方关系中的蚜虫-寄主和黄矮病-寄主的相互作用。本研究的重点放在韧皮部：(1)蚜虫只取食韧皮部，(2)黄矮病的繁殖和运输仅限于韧皮部，(3)系统对侵染和侵染的反应可能通过筛管转移。从逻辑上讲，大麦对蚜虫侵染和BYDV侵染的耐性基因在韧皮部表达，它们的一些产物通过筛管运输。基因和蛋白质表达谱可用于检测大麦品种对棉铃虫和黄矮病抗性的局部和系统反应。为此，将利用叶片组织的微阵列杂交以及韧皮部分泌物的RNA和蛋白质分析来识别基因和蛋白质表达水平的变化。一旦确定了候选基因和蛋白质，这些基因的表达就会在局部分别进行。将通过实时定量聚合酶链式反应(Real-Time-PCR)研究全身反应。随后，将比较局部和系统部位(韧皮部薄壁组织、伴生细胞、筛子分子)的表达。最后，黄矮病抗性的候选基因将被定位，以检测与黄矮病抗性相关的已知遗传位点(QTL)的共定位。这项研究将有助于更好地了解寄主对棉铃虫侵染和棉铃虫侵染的反应，特别是关于耐性寄主与敏感寄主之间韧皮部易位信号的研究。

The aphid-transmitted barley yellow dwarf (BYDV) luteovirus as well as the aphid-BYDV-interaction are both well described. The aphid-host and BYDV-host interactions in this tripartite relationship should be investigated before successful strategies against BYDV can be developed. The focus of this research is on the phloem: (1) aphids exclusively feed on the phloem, (2) BYDV propagation and transport is limited to the phloem, and (3) systemic responses to infestation and infection may be translocated via the sieve tubes. Logically, genes involved in barley tolerance against aphid infestation and BYDV infection are expressed in the phloem and some of their products translocated via sieve tubes. Gene and protein expression profiling are envisaged to detect local and systemic responses of aphid- and BYDV-tolerant barley cultivars. For that purpose, microarray hybridisation of leaf tissues and RNA and protein analysis of phloem exudates will be employed to identify shifts in gene and protein expression levels. Once candidate genes and proteins will have been identified, expression of the genes engaged in local resp. systemic response will be investigated by quantitative Real-Time-PCR. Subsequently, expression in local and systemic sites (phloem parenchyma, companion cells, sieve elements) will be compared. Finally, candidate genes for BYDV-tolerance will be mapped to detect co-localisation with known genetic loci (QTL) related to BYDV-tolerance. Expectedly, this study will provide a better understanding of the host response to aphid-infestation and infection by aphid-transmitted BYDV, in particular, with regard to the phloem-translocated signals of tolerant vs. susceptible host genotypes.