Identification, cloning and functional characterization of genes related to fire blight resistance in Malus X robusta

在包括德国和瑞士在内的几个欧洲国家，由淀粉状欧文菌引起的火疫病目前是苹果生产的主要制约因素。有效的控制只能用抗生素，但应用是特别限制和不希望的。一种对环境无害的替代方法是培育抗性苹果品种，但现有的抗性品种并不符合消费者的需求。由于培育一个新的抗病品种是非常耗时的，没有人能保证苹果会被消费者所接受，利用重组dna技术对被接受的品种进行改良是利用苹果自己的基因来解决火枯病问题的最有希望的策略。因此，基于图谱的克隆方法将用于分离QTL区域，解释最近在野生物种M. X robusta 5 （Mr5）中检测到的高达80%的表型变异。获得的序列将用于鉴定候选基因，然后在转基因植物中进行分子表征和测试。最有希望的候选基因将最终用于开发顺基因抗火疫病的苹果植株。此外，还将对接种野生型和突变型病原菌后Mr5下游作用基因和蛋白的差异表达进行鉴定和鉴定，进一步了解其抗火疫病的机制。

The fire blight disease caused by the bacterium Erwinia amylovora is currently the major constraint for apple production in several European countries including Germany and Switzerland. An effective control is only possible with antibiotics but the application is particular restricted and not desired. An environmentally sound alternative is the growing of resistant apple cultivars, but available resistant cultivars do not fit the consumer demands. Since the breeding of a new resistant cultivar is very time consuming and nobody can assure that the apple will be accepted by the consumers the use of recombinant DNA-technology for the improvement of accepted cultivars offers the most promising strategy to solve the problem of fire blight by using Malus own genes. Therefore a map based cloning approach will be used to isolate a QTL region, explaining up to 80% of the phenotypic variance, recently detected in the wild species M. X robusta 5 (Mr5). The obtained sequence will be used to identify candidate gene(s), which will then be molecular characterized and tested in transgenic plants. The most promising candidate gene(s) will be finally used to develop a cisgenic fire blight resistant apple plant. Furthermore the identification and characterization of downstream acting genes and proteins of Mr5 differentially expressed after inoculation with wild type and mutant pathogen strains will be analyzed to get more knowledge about the mechanisms of fire blight resistance.