Karyotypic Studies in Solanum Section Lasiocarpa (Solanaceae)

Abstract

Mitotic chromosomes of 13 species included in So/anum sect. Lasiocarpa were studied. All species have 2n = 24. The chromosome numbers of S. stagnate, S. felinum, and S. repandum are reported for the first time. Statistical analyses of chromosomes, genome length, and centromere position yielded estimates of karyotype composition and asymmetry. A generalized karyotype of the section shows that most of the chromosomes are metacentric (73%) or submetacentric (25.6%). Two pairs of subtelocentric chromosomes are present only in S. sessi/iflorum. Satellites are quite common, characterizing chromosomes for ten species and are attached to the short arms of either m or sm chromosomes. They could be seen in 10% to 70% of the cells. Only S. pseudo/ufo bears two satellited chromosomes, one of them attached to a long chromosome arm. Although the section is chromosomally quite homogeneous, species can be distinguished by karyotype formula, presence of satellites in a particular chromosome pair, and total chromosome length. There are no indications of major chromosomal rearrangements within the section. Using cytological data exclusively, cluster analysis indicates S. sessi/iflorum is isolated in the section. So/anum candidum and S. vestissimum are somewhat isolated as well and have unique karyological traits. So/anum pectinatum has a peculiar karyotype, but in the phenogram it is not particularly separated. Karyotype features suggest that morphological differentiation was not always followed by chromosomal divergence. The origin ofthe domesticated S. quitoense is no further elucidated by our data.

Karyotypes and fluorescent chromosome banding in Pyrrhocactus (Cactaceae)

“…In Pyrrhocactus, species diversification seems not to have been associated with large chromosome rearrangements or with polyploidy, but with cumulative small and cryptic structural changes, as suggested for other Cactaceae (Cota and Wallace 1995) and other angiosperms (e.g. Bernardello et al 1994, Acosta et al 2005, Gitaí et al 2005.…”

“…Nevertheless, cytogenetic studies are needed because chromosome numbers and karyotype analyses have been helpful in addressing systematic and evolutionary problems in many angiosperm families (e.g. Bernardello et al 1994, Shan et al 2003, Weiss-Schneeweiss et al 2003, including Cactaceae (Palomino et al 1988, Cota and Wallace 1995, Bandyopadhyay and Sharma 2000, Das and Mohanty 2006.…”

Karyotype differentiation of four Cestrum species (Solanaceae) based on the physical mapping of repetitive DNA

“…The karyotype of Cestrum species contains 2n = 2x = 16 chromosomes of similar size and shape, most of which are meta-or submetacentric except for one subtelocentric pair Greilhuber, 1992, 1993a,b). In general, Solanaceae species such as those of the genera Solanum and Capsicum (2n = 2x = 24) exhibit small chromosomes (1.2-2.4 mm for Solanum and 3.5-4.0 mm for Capsicum) and constancy in the distribution of meta-and submetacentric chromosomes (Bernardello and Anderson, 1990, Bernardello et al, 1994, Moscone, 1993. Nevertheless, the chromosomes of the Cestreae are the largest in the family, reaching up to 14 mm and containing 1.36 pg of DNA per chromosome (Berg and Greilhuber, 1992, 1993a,b, Sykorová et al, 2003a.…”

Karyotype analysis in two species ofSolanum(Solanaceae) Sect.Cyphomandropsisbased on chromosome banding

“…The most consistent morphological synapomorphies of the group are the presence of big chromosomes (4 mm long) and large amounts of nuclear DNA, which have been found in all the species of the clade analysed to date (Roe 1967;Pringle & Murray 1991, 1993Moscone 1992;Bennett & Leitch 2010). These characteristics separate these species from other members of Solanum, which have smaller chromosomes (B 4 mm) and a lower nuclear DNA content (Bernardello & Anderson 1990;Bernardello et al 1994;Acosta et al 2005;Chiarini & Bernardello 2006;Rego et al 2009;Bennett & Leitch 2010;Melo et al 2011).…”

“…These characteristics separate them from the remaining Solanum sections, which exhibit smaller chromosomes and lower DNA content (cf. Bernardello & Anderson 1990;Bernardello et al 1994;Acosta et al 2005;Chiarini & Bernardello 2006;Rego et al 2009;Bennett & Leitch 2010;Melo et al 2011).…”