Dual-color FISH karyotype and rDNA distribution analyses on four Cucurbitaceae species

Abstract

Karyotype and ribosomal DNA distribution on four Cucurbitaceae species was analyzed through dual-color fluorescence in situ hybridization (FISH) using 5S and 45S rDNA probes. Chromosome sizes varied slightly among the species with Cucumis sativus relatively the largest (~2.5 m) and Momordica charantia the smallest (~1 m). In Cucumis sativus L. (2n = 14), the 45S rDNA hybridized on the pericentromeric area of five chromosomes (metacentric a, b, c, g, and submetacentric d) and the 5S rDNA on the region proximal to the centromere of the short arm of chromosome e. In Luffa cylindrica (L.) Roem. (2n = 26), the 45S rDNA hybridized on the distal regions of the short arms of five chromosomes (metacentric a, b, c, f, and submetacentric d) and the 5S rDNA on the region proximal to the centromere of the short arm of chromosome e. In Lagenaria siceraria (Molina) Standl. (2n = 22), the 45S rDNA hybridized on the distal regions of the short arms of two chromosomes (submetacentric b and metacentric e) and the 5S rDNA juxtaposed with the 45S rDNA signal in a region proximal to the centromere on chromosome e.In Momordica charantia L. (2n = 22), the 45S rDNA hybridized on the majority of the short arms of two metacentric chromosomes (d and k) and the 5S rDNA on the proximal region of the short arm of chromosome e. The interphase and metaphase rDNA distribution and FISH karyotype analyses of the four species showed the possible fate of rDNAs through the process that lead to the interspecific variations among the cucurbits. These results will be useful in elucidating the phylogenetic relationships among Cucurbitaceae species.

Rapid amplification of four retrotransposon families promoted speciation and genome size expansion in the genus Panax

“…ginseng , and P . quinquefolius chromosome spreads and FISH procedures were performed according to dual-color FISH analysis protocols 49 . Briefly, root tips were treated with 2 mM 8-hyroxyquinoline, fixed with Carnoy’s solution, and were enzymatically digested with pectolytic enzyme solution (2% Cellulase R-10 (C224, Phytotechnology Laboratories) and 1% Pectolyase Y-23 (P8004.0001, Duchefa)) in 100 mM citrate buffer) for 1 h. Root tips were then squashed onto slides pre-cleaned with 70% ethanol.…”

Triple-color FISH Karyotype Analysis of Four Korean Wild Cucurbitaceae Species

“…whereas 45S rDNA residing on distal or terminal regions are more prone to genomic dispersion (Waminal and Kim, 2012).…”

A Cytogenetic Study of Three Japanese Cultivars of <i>Momordica charantia</i> L.

“…In a few papers, chromosome analyses with centromere positions have been performed. Waminal and Kim (2012) analyzed somatic chromosome complements for interspecific comparison and showed a representative karyotype of this species. The complement analyzed by them consisted of all metacentric chromosomes.…”

“…There are some studies for M. charantia that present karyological information, chromosome measures and karyographs (McKay 1930, Bhaduri and Bose 1947, Lombello and Pinto-Maglio 2007, Zaman and Alam 2009, Bharathi et al 2011, Waminal and Kim 2012, Kausar et al 2014), but not so many. All the studied species presented symmetrical karyomorphology.…”