title: Nucleotide diversity and linkage disequilibrium of nine genes with putative effects on flowering time in perennial ryegrass (Lolium perenne L.).
abstract: Optimization of flowering is an important breeding goal in forage and turf grasses, such as perennial ryegrass (Lolium perenne L.). Nine floral control genes including Lolium perenne CONSTANS (LpCO), SISTER OF FLOWERING LOCUS T (LpSFT), TERMINAL FLOWER1 (LpTFL1), VERNALIZATION1 (LpVRN1, identical to LpMADS1) and five additional MADS-box genes, were analyzed for nucleotide diversity and linkage disequilibrium (LD). For each gene, about 1 kb genomic fragments were isolated from 10 to 20 genotypes of perennial ryegrass of diverse origin. Four to twelve haplotypes per gene were observed. On average, one single nucleotide polymorphism (SNP) was present per 127 bp between two randomly sampled sequences for the nine genes (π = 0.00790). Two MADS-box genes, LpMADS1 and LpMADS10, involved in timing of flowering showed high nucleotide diversity and rapid LD decay, whereas MADS-box genes involved in floral organ identity were found to be highly conserved and showed extended LD. For LpMADS4, LpMADS5, LpCO, LpSFT and LpTFL1, LD extended over the entire region analyzed. The results are compared to previously published results on resistance genes within the same collection of genotypes and the prospects for association mapping of floral control in perennial ryegrass are discussed.
authors.affiliation: Aarhus University, Faculty of Agricultural Sciences, Department of Genetics and Biotechnology, Forsøgsvej 1, DK-4200 Slagelse, Denmark. Alice.Fiil@agrsci.dk
authors.forename: Alice
authors.initials: A
authors.lastname: Fiil
authors.forename: Ingo
authors.initials: I
authors.lastname: Lenk
authors.forename: Klaus
authors.initials: K
authors.lastname: Petersen
authors.forename: Christian S
authors.initials: CS
authors.lastname: Jensen
authors.forename: Klaus K
authors.initials: KK
authors.lastname: Nielsen
authors.forename: Britt
authors.initials: B
authors.lastname: Schejbel
authors.forename: Jeppe Reitan
authors.initials: JR
authors.lastname: Andersen
authors.forename: Thomas
authors.initials: T
authors.lastname: Lübberstedt
mesh_terms: D000483:Alleles; D002874:Chromosome Mapping; D035264:Flowers / Q000235:genetics / Q000502:physiology; D017343:Genes, Plant; D006239:Haplotypes / Q000235:genetics; D006579:Heterozygote; D015810:Linkage Disequilibrium / Q000235:genetics* / Q000502:physiology; D008129:Lolium / Q000235:genetics* / Q000502:physiology; D026161:MADS Domain Proteins / Q000235:genetics* / Q000502:physiology; D057865:Plant Immunity / Q000235:genetics / Q000502:physiology; D011110:Polymorphism, Genetic / Q000235:genetics* / Q000502:physiology; D011401:Promoter Regions, Genetic; D040641:Quantitative Trait Loci; D012641:Selection, Genetic; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013997:Time Factors
chemical_list: D026161:MADS Domain Proteins