title: Sequence-tagged high-density genetic maps of Zoysia japonica provide insights into genome evolution in Chloridoideae.
abstract: Zoysiagrass (Zoysia spp.), belonging to the genus Zoysia in the subfamily Chloridoideae, is widely used in domestic lawns, sports fields and as forage. We constructed high-density genetic maps of Zoysia japonica using a restriction site-associated DNA sequencing (RAD-Seq) approach and an F1 mapping population derived from a cross between 'Carrizo' and 'El Toro'. Two linkage maps were constructed, one for each of the parents. A map consisting of 2408 RAD markers distributed on 21 linkage groups was constructed for 'Carrizo'. Another map with 1230 RAD markers mapped on 20 linkage groups was constructed for 'El Toro'. The average distance between adjacent markers of the two maps was at 0.56 and 1.4 cM, respectively. Comparative genomics analysis was carried out among zoysiagrass, rice and sorghum genomes and a highly conserved collinearity in the gene order was observed among the three genomes. Chromosome collinearity was disrupted at centromeric regions for each chromosome pair between zoysiagrass and sorghum genomes. However, no obvious synteny gaps were observed across the centromeric regions between zoysiagrass and rice genomes. Two homologous chromosomes for each of the 10 sorghum chromosomes were found in the zoysiagrass genome, indicating an allotetraploid origin for zoysiagrass. The reduction of the basic chromosome number from 12 to 10 in chloridoids and panicoids took place via independent single-step nested chromosome fusion events after the two subfamilies diverged from a common ancestor. The genetic maps will assist in genome sequence assembly, targeted gene isolation and comparative genomic analyses among grasses.
authors.affiliation: Texas A&M AgriLife Research Center at Dallas, Texas A&M University System, Dallas, TX, 75252, USA.
authors.forename: Fangfang
authors.initials: F
authors.lastname: Wang
authors.affiliation: Texas A&M AgriLife Research Center at Dallas, Texas A&M University System, Dallas, TX, 75252, USA.
authors.forename: Ratnesh
authors.initials: R
authors.lastname: Singh
authors.affiliation: Texas A&M AgriLife Research Center at Dallas, Texas A&M University System, Dallas, TX, 75252, USA.
authors.forename: Anthony D
authors.initials: AD
authors.lastname: Genovesi
authors.affiliation: Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.|FAFU and UIUC-SIB Joint Center for Genomics and Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
authors.forename: Ching Man
authors.initials: CM
authors.lastname: Wai
authors.affiliation: Texas A&M AgriLife Research Center at Dallas, Texas A&M University System, Dallas, TX, 75252, USA.
authors.forename: Xiaoen
authors.initials: X
authors.lastname: Huang
authors.affiliation: Texas A&M AgriLife Research Center at Dallas, Texas A&M University System, Dallas, TX, 75252, USA.|Department of Soil & Crop Sciences, Texas A&M University, College Station, TX, 77843, USA.
authors.forename: Ambika
authors.initials: A
authors.lastname: Chandra
authors.affiliation: Texas A&M AgriLife Research Center at Dallas, Texas A&M University System, Dallas, TX, 75252, USA.|Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, USA.
authors.forename: Qingyi
authors.initials: Q
authors.lastname: Yu
mesh_terms: D005075:Biological Evolution; D002874:Chromosome Mapping; D032461:Chromosomes, Plant; D020224:Expressed Sequence Tags; D008040:Genetic Linkage; D018745:Genome, Plant; D012275:Oryza / Q000235:genetics; D006109:Poaceae / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D032983:Setaria Plant / Q000235:genetics; D045868:Sorghum / Q000235:genetics; D026801:Synteny
keywords: Chloridoideae; Zoysia; chromosome number reduction; genetic map; nested chromosome fusion