Quantitative karyotyping and dual-color FISH mapping of 5S and 18S-25S rDNA probes in the cultivatedPhaseolusspecies (Leguminosae)

Abstract

Double-color fluorescence in situ hybridization (FISH) followed by DAPI counterstaining allowed the chromosomal assignment of 5S and 18S-25S rRNA genes in the four cultivated Phaseolus Species; P. vulgaris, P. coccineus, P. acutifolius, and P. lunatus (all: 2n = 2x = 22). The rRNA gene loci display variation between species as reflected in differences of signal size and (or) number. From one to three pairs of 5S sites and one to seven pairs of 18S-25S sites were found in the diploid complements of the four taxa studied. Intraspecific variation was studied in P. vulgaris, and it is shown that the number of 18S-25S rDNA sites differs between cultivars. Cytogenetic mapping was complemented by karyotype analyses. Each of the four cultivated Phaseolus species exhibits a characteristic heterochromatin endowment, with P. acutifolius var. latifolius having the highest amount of C-band material. Quantitative karyotyping in combination with cytogenetic mapping allowed the identification of homeologous chromosomes in the different species.

Characterization of the Arachis (Leguminosae) D genome using fluorescence in situ hybridization (FISH) chromosome markers and total genome DNA hybridization

“…The 5S rRNA gene clusters have always been reported in paracentromeric position in all the Arachis species so far analyzed (Seijo et al, 2004), thus the distal position of these loci on the long arms of chromosome pair D5 is also an exclusive character of A. glandulifera. The FISH signal strength of a particular locus is positively related to the number of copies of the repeated sequences present in the cluster (Moscone et al, 1999 and references included in it). Taking in account this relationship, the fact that signal intensity of the 45S rDNA sites on chromosome pairs D1 and D6 of A. glandulifera accession SeSn 3263 was very poor may indicate that these clusters have a low number of copies.…”

“…The first set of antibodies consisted of mouse anti-biotin (Dakopatts) and sheep antidigoxigenin conjugated to fluorescein isothiocyanate (FITC) (Boehringer). The second set of antibodies consisted of rabbit anti-mouse conjugated to tetramethyl-rhodamine isothiocyanate (TRITC) (Dakopatts) and FITCArachis D genome characterization 719 (Moscone et al, 1996(Moscone et al, , 1999. Chromosomes were viewed and photographed with a Leica DMRX epifluorescence microscope (Leica) equipped with a computer-assisted Leica DC 350 digital camera system.…”

“…Detection of rRNA genes by fluorescent in situ hybridization (FISH) has proved to be a useful tool in studies of plant genome organization, chromosome homeologies, cytotaxonomy and evolution (Jiang and Gill, 1994;Moscone et al, 1999;Lim et al, 2000;Nakamura et al, 2001). Raina and Mukai (1999) applied this approach to a few Arachis species and demonstrated that the number of ribosomal rDNA loci is variable.…”

Development and Application of Molecular Markers to Breed Common Bean (Phaseolus vulgaris L.) for Resistance to Common Bacterial Blight (CBB) — Current Status and Future Directions

“…Currently, the OAC-Rex BAC library is being used to sequence the whole genome of the CBB resistance cultivar, OAC-Rex (Pauls, et al personal communication) and whole genomic sequencing of G19833 is also under way (McClean et al personal communication Cytological analysis of the common bean chromosomes has long been hampered by the small size and overall similarity of its (2n=22) chromosomes. Unambiguous identification of each bean chromosome was not possible until the double fluorescent in situ hybridization (FISH) with 45S and 5S rRNA probes, followed by 4'-6-diamidino-2-phenylindole (DAPI) counterstaining techniques were developed (Moscone et al, 1999). The first common bean mitotic chromosome nomenclature was proposed by Moscone et al (1999).…”

A Comparative Study of the Three Cucumber Cultivars Using Fluorescent Staining and Fluorescence In Situ Hybridization

“…Fluorescence dyes, especially DAPI, are normally used for counter staining in the FISH method (Moscone et al 1999, Hizume et al 2002. Although banding patterns of counterstaining in FISH are shown in some plant chromosomes, the counterstained chromosomes cannot have effective information for characterizing or identifying, due to chromosomal denaturing during the FISH process (Heng and Tsui 1993).…”