Development of an STS map of an interspecific progeny of Malus

Abstract

Simple sequence repeat (SSR) markers developed from Malus, as well as Prunus, Pyrus and Sorbus, and some other sequence-tagged site (STS) loci were analysed in an interspecific F 1 apple progeny from the cross 'Fiesta' × 'Totem' that segregated for several agronomic characters. A linkage map was constructed using 259 STS loci (247 SSRs, four SCARs and eight known-function genes) and five genes for agronomic traits-scab resistance (Vf), mildew resistance (Pl-2), columnar growth habit (Co), red tissues (Rt) and green flesh background colour (Gfc). Ninety SSR loci and three genes (ETR1, Rt and Gfc) were mapped for the first time in apple. The transferability of markers from other Maloideae to Malus was found to be around 44%. The loci are spread across 17 linkage groups, corresponding to the basic chromosome number of Malus and cover 1,208 cM, approximately 85% of the estimated length of the apple genome. Interestingly, we have extended the top of LG15 with eight markers covering 25 cM. The average map density is 4.7 cM per marker; however, marker density varies greatly between linkage groups, from 2.5 in LG14 to 8.9 in LG7, with some areas of the genome still in need of further STS markers for saturation.

Development of “universal” gene-specific markers from Malus spp. cDNA sequences, their mapping and use in synteny studies within Rosaceae

“…"Totem" (F × T; Fernández-Fernández et al 2008), the diploid Fragaria reference bin mapping population (N=6) Fragaria vesca 815 × Fragaria nubicola 601 F 2 (FV × FN; Sargent et al 2008), and the Prunus reference bin mapping population (N=6) Prunus dulcis "Texas" × P. persica "Earlygold" F 2 (T × E; Howad et al 2005). An additional diploid Fragaria population-the 815×903BC population (N=93) of Nier et al (2006)was used to confirm the map position of one marker where the segregation scores produced using the FV × FN bin set were ambiguous.…”

“…Alleles at segregating loci in the F × T mapping population were coded for analysis using JoinMap 4.0 and incorporated into the dataset of Fernández-Fernández et al (2008) as follows. Genetic distances were calculated using regression mapping applying the Kosambi mapping function and marker positions were determined using a recombination fraction threshold of 0.35, ripple value of 1.0, jump threshold of 3.0, and triplet threshold of 5.0.…”

“…The LOD threshold for acceptance of linkage between markers was ≥3.0. Markers were assimilated into the linkage groups defined by Fernández-Fernández et al (2008) and the map presented was visualized using MapChart 2.0 for Windows (Voorrips 2002).…”

Shift in polyphenol profile and sublethal phenotype caused by silencing of anthocyanidin synthase in apple (Malus sp.)

“…Recently, three nearly identical R2R3 MYB transcription factors (MdMYBA,MdMYB1 and MdMYB10) were shown to be involved in the regulation of red coloration in apple (Takos et al 2006;Ban et al 2007;Espley et al 2007). Genetically it was shown that the red pigmentation of Xesh and foliage can be determined by a unique single locus Rni (R for red and ni for niedzwetzkyana) on linkage group 9 of apple, which co-segregates with MdMYB10 (Chagné et al 2007;Fernández-Fernádez et al 2008). The MdMYBA gene was also mapped at the same region on LG9 in a population 'Delicious' £ 'Mitsubakaido' (Ban et al 2007).…”

Construction of an integrated consensus map of the apple genome based on four mapping populations

“…Silfverberg-Dilworth et al (2006) constructed a map, which is currently used as reference map, by adding a new set of SSR markers to the previous linkage map. A new map including several major genes and summarizing the position of 247 SSR was also recently published by Fernandez-Fernandez et al (2008).…”