Identification and functional characterization of genes involved in the process of root-specific B chromosome elimination in Aegilops speltoides

生物体的所有细胞不一定都含有相同的基因组。一些真核生物在不同器官的细胞之间表现出巨大的基因组差异，这是由于染色体或其片段的程序性消除造成的。以山羊草Aegilops speltoides （2n = 2x = 14）为模型，我们证明了B染色体的消除是一个严格控制和高效的根特异性过程。多余的B染色体(B)是在真菌、植物和动物中发现的必不可少的基因组元素。在之前的一项研究中，我们发现，在胚胎分化开始时，根限制性Bs的消除始于胚根形成，并通过微核发生。这可能是由于长时间的姐妹染色单体内聚而导致的不分离。但B染色体消除的分子机制仍不清楚。在应用项目的框架内，对这一现象的深入表征旨在识别控制消除过程的转录本。将带和不带b的胚胎的转录组进行比较，以破译单子叶植物中控制染色体消除的转录本/基因。候选基因将使用病毒诱导的基因沉默（VIGS）方法进行功能评估

Not necessarily all cells of an organism contain the same genome. Some eukaryotes exhibit dramatic genomic differences between cells of different organs, resulting from programmed elimination of chromosomes or their fragments. Using the goatgrass Aegilops speltoides (2n = 2x = 14) as a model, we demonstrated that the elimination of B chromosomes is a strictly controlled and a highly efficient root-specific process. Supernumerary B chromosomes (Bs) are dispensable genomic elements found in fungi, plants and animals. In a previous study we showed that the root-restricted elimination of Bs starts with radicle formation at the onset of embryo differentiation and occurs via micronucleation. It is likely caused by nondisjunction due to prolonged sister-chromatid cohesion. But the molecular mechanism underlying B chromosome elimination remains unknown. In frame of the applied project an in-depth characterization of this phenomenon is aimed to identify transcripts controlling the process of elimination. The transcriptomes of embryos with and without Bs will be compared to decipher transcripts/genes controlling chromosome elimination in a monocot species. Candidate genes will be functionally evaluated using a virus-induced gene silencing (VIGS) approach