Construction of a reference molecular linkage map of globe artichoke (Cynara cardunculus var. scolymus)

Abstract

The genome organization of globe artichoke (Cynara cardunculus var. scolymus), unlike other species belonging to Asteraceae (=Compositae) family (i.e. sunflower, lettuce and chicory), remains largely unexplored. The species is highly heterozygous and suffers marked inbreeding depression when forced to self-fertilize. Thus a two-way pseudo-testcross represents the optimal strategy for linkage analysis. Here, we report linkage maps based on the progeny of a cross between globe artichoke (C. cardunculus var. scolymus) and cultivated cardoon (C. cardunculus var. altilis). The population was genotyped using a variety of PCR-based marker platforms, resulting in the identification of 708 testcross markers suitable for map construction. The male map consisted of 177 loci arranged in 17 major linkage groups, spanning 1,015.5 cM, while female map was built with 326 loci arranged into 20 major linkage groups, spanning 1,486.8 cM. The presence of 84 loci shared between these maps and those previously developed from a cross within globe artichoke allowed for map alignment and the definition of 17 homologous linkage groups, corresponding to the haploid number of the species. This will provide a favourable property for QTL scanning; furthermore, as 25 mapped markers (8%) correspond to coding regions, it has an additional value as functional map and might represent an important genetic tool for candidate gene studies in globe artichoke.

New genetic maps for globe artichoke and wild cardoon and their alignment with an SSR-based consensus map

“…The high level of inbreeding depression experienced by C. cardunculus (Cravero et al 2002) prevents either backcross, F 2 or recombinant inbreed line populations being used for mapping quantitative traits, so instead the double pseudo-testcross approach was taken, as also successfully used by Lanteri et al (2006), Portis et al (2009) and Sonnante et al (2011). Mapping population individuals obtained from other globe artichoke x wild cardoon crosses have been shown to vary widely with respect to both quantitative and qualitative characters (Sonnate et al 2011;Lanteri et al 2012), confirming that a high level of heterozygosity has been retained in both wild and cultivated germplasm (Portis et al 2005a(Portis et al , 2005bMauro et al 2009Mauro et al , 2012).…”

“…A comparison of heterozygosity between the mapping parents used by Portis et al (2009) showed that fewer loci were informative in the cultivated cardoon than in the globe artichoke variety "Romanesco C3". An explanation for this difference reflected the fact that while the latter is propagated vegetatively, the former is a seed-propagated variety.…”

Morphology and SSR fingerprinting of newly developed Cynara cardunculus genotypes exploitable as ornamentals

“…Microsatellites (SSRs) are particularly suited to DNA fingerprinting as well as for identifying potential parental genotypes for highly segregating populations development, given their robustness and informativeness. Over the last few years, a substantial set of globe artichoke SSR assays has been developed (Acquadro et al 2003(Acquadro et al , b, 2009, and these have been used to assess genetic diversity Portis et al 2005a, b, c) and to construct genetic linkage maps (Lanteri et al 2006;Portis et al 2009). …”

Genetic Diversity Assessment in European Cynara Collections

“…The molecular markers were used mainly for variety identification and genetic diversity and relatedness investigations (Tivang et al 1996;Sonnante et al 2002Sonnante et al , 2008Crinò et al 2008), plant breeding as selection tools and to characterize parental lines in F1 hybrid constitution (Lo Bianco et al 2011), as well as to identify the most probable progenitors of a given hybrid (Messmer et al 2002). Furthermore, genetic linkage maps have also been recently developed in artichoke (Lanteri et al 2006;Lanteri and Portis 2008;Acquadro et al 2009;Portis et al 2009;Sonnante et al 2011b). The first two were from the same mapping population obtained by crossing two artichoke types, the other ) was obtained by using an F1 population derived from a cross between artichoke and cultivated cardoon, while the last (Sonnante et al 2011b) utilized a cross between artichoke and wild cardoon.…”

“…The first two were from the same mapping population obtained by crossing two artichoke types, the other ) was obtained by using an F1 population derived from a cross between artichoke and cultivated cardoon, while the last (Sonnante et al 2011b) utilized a cross between artichoke and wild cardoon. Also, some specific genes are reported in the linkage maps, such as genes involved in the synthesis of phenylpropanoid compounds (De Paolis et al 2008;Portis et al 2009;Menin et al 2010;Sonnante et al 2010).…”