%0 Journal Article
%T Comparative Genomics in Perennial Ryegrass (Lolium perenne L.): Identification and Characterisation of an Orthologue for the Rice Plant Architecture-Controlling Gene OsABCG5
%A Hiroshi Shinozuka
%A Noel O. I. Cogan
%A German C. Spangenberg
%A John W. Forster
%J International Journal of Plant Genomics
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/291563
%X Perennial ryegrass is an important pasture grass in temperate regions. As a forage biomass-generating species, plant architecture-related characters provide key objectives for breeding improvement. In silico comparative genomics analysis predicted colocation between a previously identified QTL for plant type (erect versus prostrate growth) and the ortholocus of the rice OsABCG5 gene (LpABCG5), as well as related QTLs in other Poaceae species. Sequencing of an LpABCG5-containing BAC clone identified presence of a paralogue (LpABCG6) in the vicinity of the LpABCG5 locus, in addition to three other gene-like sequences. Comparative genomics involving five other 5 grass species (rice, Brachypodium, sorghum, maize, and foxtail millet) revealed conserved microsynteny in the ABCG5 ortholocus-flanking region. Gene expression profiling and phylogenetic analysis suggested that the two paralogues are functionally distinct. Fourteen additional ABCG5 gene family members, which may interact with the LpABCG5 gene, were identified through sequencing of transcriptomes from perennial ryegrass leaf, anther, and pistils. A larger-scale phylogenetic analysis of the ABCG gene family suggested conservation between major branches of the Poaceae family. This study identified the LpABCG5 gene as a candidate for the plant type determinant, suggesting that manipulation of gene expression may provide valuable phenotypes for perennial ryegrass breeding. 1. Introduction Perennial ryegrass is an economically important temperate pasture grass species and a diploid ( ) member of the Poaceae family which includes other major cereal crops such as rice (Oryza sativa L.), wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), sorghum (Sorghum bicolor L.), and maize (Zea mays L.) [1, 2]. Due to superior herbage digestibility and grazing tolerance, perennial ryegrass has been a primary target for molecular breeding among forage and turf crops [3]. Following establishment of a whole-genome genetic map consisting of 7 linkage groups (LGs) [4, 5], a number of quantitative trait loci (QTLs) related to variation for herbage yield and quality have been identified [6¨C9]. Plant morphological traits contribute to such variation in pasture grass species and are largely controlled by genetic factors [6, 10]. For example, evaluation of a one-way pseudotestcross genetic mapping population obtained a broad sense heritability ( ) value of 0.73 for the herbage fresh weight character, and significant correlations were observed between this and other traits such as plant height and tiller number [6].
%U http://www.hindawi.com/journals/ijpg/2011/291563/