Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: 10/5/2007
Publication Date: 1/10/2008
Citation: Faris, J.D., Zhang, Z., Fellers, J.P., Gill, B.S. 2008. Micro-colinearity between rice, Brachypodium, and Triticum monococcum at the wheat domestication locus Q. Plant and Animal Genome Conference XVI abstract pg. 262.
Technical Abstract: Brachypodium, a wild temperate grass with a small genome, was recently proposed as a new model organism for the large-genome grasses. However, few studies have been conducted to determine the level of conservation at the DNA level (micro-colinearity) between Brachypodium and wheat. In this study, we evaluated gene content and micro-colinearity between diploid wheat (Triticum monococcum), Brachypodium sylvaticum, and rice at a local genomic region harboring the major wheat domestication gene Q. Gene density was much lower in T. monococcum (one per 41 kb) compare to B. sylvaticum (one per 14 kb) and rice (one per 10 kb) due to gene duplication and an abundance of transposable elements within intergenic regions. Good levels of micro-colinearity were observed among all three species with a few exceptions. An F-box-like gene present as a single copy in B. sylvaticum and four copies in T. monococcum was absent in rice, and B. sylvaticum contained two genes not present within the orthologous regions of T. monococcum and rice. Also, a 40S ribosomal-like gene present in T. monococcum and rice was highly degenerate in B. sylvaticum. Phylogenetic analysis of Q and leukotriene A-4 hydrolase-like gene orthologs, which were colinear among the three species, showed that Brachypodium is more closely related to wheat than rice is, which agrees with previous studies. We conclude that Brachypodium will provide a useful tool for comparative genomics, gene annotation, and the study of evolutionary relationships among the grasses, but will not preclude the need to conduct large-scale genomics experiments in the Triticeae.