Construction of the first genetic linkage map of Japanese gentian (Gentianaceae)

Abstract

BackgroundJapanese gentians (Gentiana triflora and Gentiana scabra) are amongst the most popular floricultural plants in Japan. However, genomic resources for Japanese gentians have not yet been developed, mainly because of the heterozygous genome structure conserved by outcrossing, the long juvenile period, and limited knowledge about the inheritance of important traits. In this study, we developed a genetic linkage map to improve breeding programs of Japanese gentians.ResultsEnriched simple sequence repeat (SSR) libraries from a G. triflora double haploid line yielded almost 20,000 clones using 454 pyrosequencing technology, 6.7% of which could be used to design SSR markers. To increase the number of molecular markers, we identified three putative long terminal repeat (LTR) sequences using the recently developed inter-primer binding site (iPBS) method. We also developed retrotransposon microsatellite amplified polymorphism (REMAP) markers combining retrotransposon and inter-simple sequence repeat (ISSR) markers. In addition to SSR and REMAP markers, modified amplified fragment length polymorphism (AFLP) and random amplification polymorphic DNA (RAPD) markers were developed. Using 93 BC1 progeny from G. scabra backcrossed with a G. triflora double haploid line, 19 linkage groups were constructed with a total of 263 markers (97 SSR, 97 AFLP, 39 RAPD, and 30 REMAP markers). One phenotypic trait (stem color) and 10 functional markers related to genes controlling flower color, flowering time and cold tolerance were assigned to the linkage map, confirming its utility.ConclusionsThis is the first reported genetic linkage map for Japanese gentians and for any species belonging to the family Gentianaceae. As demonstrated by mapping of functional markers and the stem color trait, our results will help to explain the genetic basis of agronomic important traits, and will be useful for marker-assisted selection in gentian breeding programs. Our map will also be an important resource for further genetic analyses such as mapping of quantitative trait loci and map-based cloning of genes in this species.

Construction of a reference genetic linkage map for carnation (Dianthus caryophyllus L.)

“…Thus, the regions of distortion differed between the two linkage maps. Distorted segregations in linkage maps have been reported for other ornamentals, including Rhododendron [ 30 ], diploid rose [ 31 - 34 ], Asiatic hybrid lily [ 35 ], and Japanese gentian [ 27 ]. The causes of segregation distortion have been suggested to include aneuploidy, chromosomal translocation, competition among gametes, and the inheritance of alleles affecting the viability of the zygote, embryo, or seedling [ 1 , 36 , 37 ].…”

Production of interspecific hybrids between Japanese gentians and wild species of <i>Gentiana</i>

“…The hybridity of plants regenerated was examined using simple sequence repeat (SSR) markers (Sato-Ushiku et al 2011) and sequence characterized amplified region (SCAR) markers (Nakatsuka et al 2012, Shimada et al 2009, M. Nishihara personal communication) based on the length polymorphisms in introns of flavonoid biosynthetic genes and transcription factor gene. Total DNA was extracted from leaves by CTAB method (Murray and Thompson 1980).…”

Development of basic technologies for improvement of breeding and cultivation of Japanese gentian

“…The molecular markers can also be used for cultivar identification and linkage analysis ( Shimada et al 2009 , Ushiku et al 2011 ). In fact, the first genetic linkage map for Japanese gentian was generated using simple sequence repeat (SSR) and several DNA markers ( Nakatsuka et al 2012 ). Japanese gentians originally had blue flowers, but some mutant lines have arisen with pink or white flowers that can be used as breeding materials.…”