In Silico Identification and Characterization of Wheat 4AL - Triticum militinae Introgression

Common wheat has adapted to a wide range of environmental conditions due to the plasticity of its hexaploid genome. The ability of wheat to withstand abiotic and biotic stress can be increased by introducing new genes and alleles from related species. Although alien gene introgression represents a powerful approach for wheat improvement, the knowledge of underlying mechanisms remains limited. The introgression of a segment of T. militinae genome to the long arm of wheat chromosome 4A (4AL) makes this arm a suitable model to study chromosomal rearrangements that accompanied wheat evolution and domestication. In addition to the recent introgression, 4AL arm carries a large pericentromeric inversion and two translocations from chromosome arms 5AL and 7BS. We have flow-sorted 4AL arm of cv. Chinese Spring (4AL-CS) and the same arm with T. militinae translocation (4AL-TM), and sequenced their DNA by Illumina. The sequences of 4AL-CS and 4AL-TM comprise 6775 and 6205 loci identified by mapping with Chinese Spring whole RNA-seq data, respectively. Out of all identified loci, 1145 were identical in the two arms. To characterize the size, translocation breakpoints and the introgressed region in 4AL-TM, we used a battery of comparative analyses based on virtual gene order (GenomeZipper). This approach may be used to characterize alien segments in wheat introgression lines. This work has been supported by the Czech Ministry of Education, Youth and Sports (OP VK CZ.1.07/2.3.00/20.0165), Internal Grant Agency of UP (PrF-2013-003), and by the Estonian Ministry of Agriculture.