Chromosome Structure of Wild Wheat Relative Aegilops uniaristata

INTRODUCTION: Homoeologous chromosomes within the grass tribe Triticeae have largely retained their cross-species colinearity. However, prior studies suggest that the karyotype of Aegilops uniaristata, a diploid wild relative of wheat (genome NN, 2n = 2x = 14), is noticeably different from most of the Triticeae species. METHODS: We used fluorescence in situ hybridization with a large collection of probes hybridizing to repetitive and coding regions of the Triticeae genomes to perform comparative cytogenetic analysis and establish the macrostructure of Ae. uniaristata chromosomes. RESULTS: Compared to wheat, all chromosomes of Ae. uniaristata, with the exception of 5N, were found significantly rearranged due to multiple inter- and intrachromosomal translocations and inversions. CONCLUSION: The N-genome structure revealed in our study is useful for understanding karyotype evolution and facilitating introgression from Ae. uniaristata and the N-genome of polyploid Aegilops species for wheat improvement.