Karyological and genome size insights into cardoon (Cynara cardunculusL., Asteraceae) in Tunisia

Abstract

This study contributes the first genome size data for wild populations of Cynara cardunculus, the presumed progenitor of artichoke and cultivated cardoon. C-values estimated by flow cytometry are 2C = 1.98-2.14(3.03) pg for wild cardoon (10 populations), 2C = 2.10-2.11 pg for cultivated cardoon (two accessions) and 2C = 2.05 pg for artichoke (one accession). Chromosome counting (carried out for all material except the artichoke) establishes diploidy in all accessions. In order to provide a phylogenetic framework for Tunisian populations, internal transcribed spacer (ITS) region was sequenced and analysed together with previously published Cynara sequences. The wild and crop cardoons present similar karyological features and genome sizes despite strong morphological differentiation, with the single exception of a Tunisian population (from Tajerouine), which exhibits a 42-53% higher genome size. Along with Sicilian individuals, Tunisian wild C. cardunculus appear genetically closer to artichoke and cardoon than to studied wild relatives from the remaining distribution. This highlights the crucial importance of taking into consideration the North African territory in deciphering the history of C. cardunculus crop domestication.

First detailed karyo-morphological analysis and molecular cytological study of leafy cardoon and globe artichoke, two multi-use Asteraceae crops

“…The genomes size measured in this study for leafy cardoon (2C = 2.20 pg) and globe artichoke (2C = 2.40 pg) are slightly different to those previously reported by Khaldi et al (2014) and Marie and Brown (1993), respectively. Khaldi et al (2014) reported a range of variability in DNA content, from 2C = 1.98 to 3.03 pg, in 10 populations of wild cardoon, and 2C = 2.05 and 2.10-2.11 pg for a single variety of globe artichoke and for two varieties of cultivated cardoon, respectively, while Marie and Brown (1993) stated a DNA content of 2C = 2.22 pg for globe artichoke.…”

“…Khaldi et al (2014) reported a range of variability in DNA content, from 2C = 1.98 to 3.03 pg, in 10 populations of wild cardoon, and 2C = 2.05 and 2.10-2.11 pg for a single variety of globe artichoke and for two varieties of cultivated cardoon, respectively, while Marie and Brown (1993) stated a DNA content of 2C = 2.22 pg for globe artichoke. The differences between our estimates in DNA content and those of Marie and Brown (1993) and Khaldi et al (2014) can be attributed to the DNA content estimation for the internal standard ( Pisum sativum ). Both works used 2C = 8.37 pg, while we employed 2C = 9.09 pg from Doležel et al (1998).…”

“…Both works used 2C = 8.37 pg, while we employed 2C = 9.09 pg from Doležel et al (1998). Possible intra-specific genome size variability was reported by Khaldi et al (2014) which may also account for differences in DNA content estimates.…”

Cytogenetic characterization of cultivated globe artichoke (Cynara cardunculusvar.scolymus) and cardoon (C. cardunculusvar.altilis)

“…This evolutionary scenario is supported by molecular analyses that indicate close relationships between the artichoke and the wild cardoon from the Eastern Mediterranean, whereas cultivated cardoons are similar to the Western wild cardoons (Sonnante, Carluccio, et al 2007;Sonnante et al 2008). Despite such progress in the evolutionary field, the cytogenetic knowledge of C. cardunculus is still scarce, being limited to the chromosome number and little basic information on the chromosome morphology of artichoke (Giorgi et al 2013;Khaldi et al 2014). Molecular cytogenetic techniques, such as FISH (fluorescent in situ hybridization), which are known to be extremely valuable tools for investigating species with small chromosomes, have not been so far applied in C. cardunculus.…”

New or rare data on chromosome numbers and karyomorphology of some taxa in the subgenusSeriphidium(Bess.) Rouy. (Artemisia, Asteraceae) in Turkey

“…Despite its relevance, the chromosome number is only known for around 25% of angiosperms (Stuessy 2009). The Asteraceae are one of the families in which major efforts towards chromosome number and genome size determination have been made (Watanabe et al 2007;Semple and Watanabe 2009;Meng et al 2012;Mousavi et al 2013;Olanj et al 2013;Khaldi et al 2014). In particular, hypotheses on basic chromosome numbers in Asteraceae have been hampered by a lack of understanding of which genera were basal within tribes and which tribes were basal within the family.…”