Chromosome Structure of Wild Wheat Relative Aegilops uniaristata

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.

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.

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.

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.