Karyotypes, Heterochromatin and Physical Mapping of Rdna in Vine Cactaceae (Hylocereineae)

Moreno, Natalia Cecilia; Peñas, M. Laura Las; Bernardello, Gabriel

doi:10.2985/026.020.0106

Cited by 8 publications

(4 citation statements)

References 47 publications

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“…On the other hand, 5S rDNA sites had a variable position in the family (Las Peñas & al., 2011, 2014, 2017, 2019; Moreno & al., 2015a,b; Castro & al., 2016). In Pterocactus species, with the exception of at least P. gonjianii , the number of 5S sites increases with the ploidy level.…”

Section: Discussionmentioning

confidence: 99%

“…In Pterocactus species, with the exception of at least P. gonjianii , the number of 5S sites increases with the ploidy level. This proportional increase has been detected in other Cactaceae (Las Peñas & al., 2011, 2014, 2017; Moreno & al., 2015a,b; Castro & al., 2016) and angiosperms as well (Frello & Heslop‐Harrison, 2000; Datson & Murray, 2006; Urdampilleta & al., 2006; Deanna & al., 2018). As a whole, in angiosperms the number of 5S loci was reduced in different lineages, whereas the number of 18S‐5.8S‐26S tends to be preserved (e.g., Volkov & al., 2017; Deanna & al., 2018), which is opposite to that found in Pterocactus and Cactaceae (Las Peñas & al., 2011, 2014, 2017, 2019; Moreno & al., 2015a,b).…”

Section: Discussionmentioning

confidence: 99%

“…Cytological data contribute to clarifying the origin, speciation and the phylogenetic relationships of flowering plants (e.g., Weiss‐Schneeweiss & Schneeweiss, 2013; Chiarini & al., 2018; Tapia‐Pastrana & al., 2020), including Cactaceae (e.g., Majure & al., 2012; Moreno & al., 2015a; Las Peñas & al., 2019). Cacti are highly conservative in some chromosomal characteristics, such as the basic number ( x = 11) and highly symmetrical karyotypes (e.g., Ross, 1981; Pinkava & Parfitt, 1982; Cota & Wallace, 1995; Bandyopadhyay & Sharma, 2000; Las Peñas & al., 2008; Moreno & al., 2015a,b).…”

Section: Discussionmentioning

confidence: 99%

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Divergence time estimation and mapping of morphological and cytogenetical data in the southern South American geophyte genus Pterocactus (Cactaceae)

Peñas

Bernardello

2021

TAXON

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Pterocactus has 10 species endemic to restricted areas of the Argentine Monte and Patagonia regions, also growing in neighbouring Chile. We analysed phylogenetic relationships between its species, based on plastid DNA sequences (psbA‐trnH, rpl16, trnH‐matK), exomorphological features (spine type and size, stem segment form, flower position, epidermis colour, areole pubescence, stem surface) and cytogenetical traits (genome size, somatic chromosome number). Traits were mapped using character mapping and ancestral state reconstruction to understand the dynamics of evolutionary changes. Pterocactus was monophyletic. Two lineages were recovered: clade A (with P. fischeri diverging early and P. reticulatus, P. valentinii, P. megliolii, P. gonjianii, and both P. tuberosus forms) and clade B (with P. neuquensis diverging first and P. araucanus and P. hickenii). Both samples examined of P. australis were paraphyletic. It was estimated that Pterocactus split from its sister group at 9.38 mya. The crown group age was estimated to be 7.69 myr. Species showed x = 11 with different ploidy levels (2n = 22, 44, 99, ca. 110, and 154); only P. tuberosus f. tuberosus was diploid. The numbers were typical of each taxon studied, and polyploidy was important in its diversification. Two 18S‐5.8S‐26S sites were detected regardless of the ploidy level, except P. fischeri with four sites and 2n = ca. 110. The number of 5S sites was 2 in P. gonjianii and the diploid P. tuberosus f. tuberosus, 4 in the tetraploid P. tuberosus f. lelongii, 10 in the probably decaploid P. fischeri and 8 in P. araucanus of unknown chromosome number. The genome size ranged from 2C = 4.94 pg in P. megliolii of unknown chromosome number to 2C = 16.68 pg in the tetradecaploid P. hickenii. The ancestor is reconstructed as a dwarf shrub with cylindrical central spines of 16.35–31.2 mm long, non‐woolly areoles, cylindrical to globose/obpyriform stem segments, non‐tuberculate stem surface, lateral flower position, green/brown to violet epidermis, probably diploid, and with a genome size between 1.10 and 1.23 pg.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Divergence time estimation and mapping of morphological and cytogenetical data in the southern South American geophyte genus Pterocactus (Cactaceae)

Peñas

Bernardello

2021

TAXON

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“…We only detected CMA + /DAPI − heterochromatin, always associated with the NOR. Such heterochromatin distribution, showing colocalization of GC‐rich regions and rDNA, is rather common for numerous plant species (Siljak‐Yakovlev et al, 2003; Moreno et al, 2015; Las Peñas et al ., 2017). According to Guerra (2000), the most characteristic heterochromatin region detected with fluorochromes is the NOR, almost always CMA+/DAPI − .…”

Section: Discussionmentioning

confidence: 99%

Molecular Cytogenetic Characterization of the Native Forage GrassTrichloris crinita

et al. 2019

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Trichloris crinita (Lag.) Parodi is a perennial forage grass native to—and of wide distribution in—arid and semiarid regions of the American continent. In addition to its good forage quality, this species is particularly valued in these drylands due to its high tolerance to drought, salinity, trampling, and grazing. Genetic and cytogenetic information for T. crinita is very scarce, hindering progress in genetic research and breeding of the species. We describe chromosome numbers, karyotypes, heterochromatin distribution, physical mapping of ribosomal DNA (rDNA) genes (18–5.8–26S and 5S) by fluorescent in situ hybridization (FISH), and chromosome pairing in meiotic cells for the first time in T. crinita accessions. Karyotype based on chromosome morphology and cytogenetic landmarks are presented for eight T. crinita accessions. Physical mapping of rDNA loci revealed variation in the number, size, and intensity of the 18–5.8–26S FISH signals, whereas 5S rDNA produced two signals per accession. Considering a basic chromosome number of 10, as reported for most Chloridoideae species and the facts that all 20 T. crinita accessions analyzed had 40 somatic chromosomes, that only bivalent chromosome pairings were observed in meiosis, and that chromosome morphology and sizes revealed high similarity between pairs of chromosomes, along with other reproductive features of the species, strongly suggest that T. crinita is an allotetraploid (2n = 4x = 40). Our cytogenetic data represent a useful resource for advancing cytogenetic research and breeding in T. crinita.

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Phylogenetic reconstruction of the genus Tephrocactus (Cactaceae) based on molecular, morphological, and cytogenetical data

Peñas

Kiesling

Bernardello

2019

TAXON

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Tephrocactus comprises species mainly endemic to Argentina. Molecular phylogenetic analyses of all proposed species of the genus as well as classical (chromosome number, karyotype) and molecular cytogenetical techniques (DNA content, heterochromatin amount, rDNA genes) were conducted. Sequence data of two plastid DNA markers of Tephrocactus taxa were analyzed. Evolution of character states of cytogenetical and morphological (growth form, presence of leaves, glochids and tepal spiny mucrons, flower color) traits were reconstructed. Species show x = 11 with different ploidy levels (2n = 22, 44, 66, 77, 242, 319), small chromosomes, and symmetrical karyotypes. Tephrocactus was recovered as monophyletic with three main clades including 12 species, using molecular and morphological data. Tephrocactus geometricus, T. halophilus, and T. paediophilus are recognized as distinct species. Banding patterns showed CMA + /DAPI − constitutive heterochromatin associated with nuclear organized regions. Heterochromatin amount ranged from 2.99% to 6.50%. The 18S-5.8S-26S ribosomal DNA (rDNA) sites coincided with the CMA + /DAPI − signals. The 5S sites varied with ploidy levels of the taxa. DNA content (2C = 1.99-24.50 pg) had a significant and positive correlation with ploidy level and the number of rDNA genes. The ancestor is reconstructed to have been a dwarf shrub with strong articulation, glochids, and deciduous leaves, white, pink or pearly tepals without spiny mucrons, 2n = 22, low DNA content, and one pair of each rDNA gene followed by three polyploidization events. Tephrocactus diversification has been associated with polyploidy and few cumulative small cryptic chromosomal changes.

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Karyotypes, Heterochromatin and Physical Mapping of Rdna in Vine Cactaceae (Hylocereineae)

Cited by 8 publications

References 47 publications

Divergence time estimation and mapping of morphological and cytogenetical data in the southern South American geophyte genus Pterocactus (Cactaceae)

Divergence time estimation and mapping of morphological and cytogenetical data in the southern South American geophyte genus Pterocactus (Cactaceae)

Molecular Cytogenetic Characterization of the Native Forage GrassTrichloris crinita

Phylogenetic reconstruction of the genus Tephrocactus (Cactaceae) based on molecular, morphological, and cytogenetical data

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