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

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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