Chromosomal Locations of 5S and 45S rDNA in Gossypium Genus and Its Phylogenetic Implications Revealed by FISH

Gan, Yimei; Liu, Fang; Chen, Dan; Wu, Qiong; Qin, Qin; Wang, Chunying; Li, Shaohui; Zhang, Xiangdi; Wang, Yuhong; Wang, Kunbo

doi:10.1371/journal.pone.0068207

Cited by 33 publications

(18 citation statements)

References 42 publications

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“…Gossypium, a close relative to Hibiscus in the Malvaceae family, is composed of diploids and allopolyploids. A study of 5S and 45S rDNA revealed that most diploids had two 5S rDNA signals and all allotetraploid species had four 5S rDNA signals (Gan et al, 2013), compared with only two 5S rDNA signals in tetraploid H. syriacus. In addition to among-ploidy level variation in rDNA signals, it is possible to have variation within the same ploidy for a species.…”

Section: Methodsmentioning

confidence: 99%

Variation in Genome Size, Ploidy, Stomata, and rDNA Signals in Althea

Lattier¹,

Chen²,

Contreras³

2019

J. Amer. Soc. Hort. Sci.

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Althea (Hibiscus syriacus) is a shrub prized for its winterhardiness and colorful summer flowers. Altheas are tetraploids (2n = 4x = 80); however, breeders have developed hexaploids and octoploids. Previous studies report anatomical variation among polyploids, including stomata size. The purpose of this study was 4-fold. First, identify genome size and ploidy variation in cultivars via flow cytometry and chromosome counts. Second, create a ploidy series consisting of 4x, 5x, 6x, and 8x cytotypes. Third, investigate the ploidy series for variation in stomatal guard cell lengths, stomatal density, and copy number of fluorescent ribosomal DNA (rDNA) signals. Fourth, investigate segregation patterns of rDNA signals in a subset of pentaploid seedlings. Flow cytometry revealed most cultivars to be tetraploid with holoploid 2C genome sizes from 4.55 ± 0.02 to 4.78 ± 0.06 pg. Five taxa (‘Aphrodite’, ‘Pink Giant’, ‘Minerva’, Azurri Satin®, and Raspberry Smoothie™) were hexaploids (6.68 ± 0.13 to 7.05 ± 0.18 pg). Peppermint Smoothie™ was a cytochimera with tetraploid cells (4.61 ± 0.06 pg) and octoploid cells (8.98 ± 0.13 pg). To create pentaploids, reciprocal combinations were made between hexaploid ‘Pink Giant’ and tetraploid cultivars. To create octoploids, seedlings were treated with agar solutions containing 0.2% colchicine or 125 μM oryzalin. Guard cell lengths were significantly different among the four cytotypes: 4x (27.36 ± 0.04 μm), 5x (30.35 ± 1.28 μm), 6x (35.59 ± 0.63 μm), and 8x (40.48 ± 1.05 μm). Measurements of stomatal density revealed a precipitous decline in average density from the 4x cytotype (398.22 ± 15.43 stomata/mm2) to 5x cytotype (194.06 ± 38.69 stomata/mm2) but no significant difference among 5x, 6x, and 8x cytotypes. Fluorescent in situ hybridization (FISH) revealed an increase in 5S and 45S rDNA signals that scaled with ploidy: 4x (two 5S + four 45S), 6x (three 5S + six 45S), and 8x (four 5S + eight 45S). However, pentaploid (5x) seedlings exhibited random segregation of rDNA signals between the 4x and 6x cytotypes, including all six possible combinations (two 5S, three 5S) × (four 45S, five 45S, six 45S).

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Section: Methodsmentioning

confidence: 99%

Variation in Genome Size, Ploidy, Stomata, and rDNA Signals in Althea

Lattier¹,

Chen²,

Contreras³

2019

J. Amer. Soc. Hort. Sci.

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“…Modern methodologies and modifications, such as the development of probes from specificity for highly repeated sequences to single-copy sequence ( Desel et al 2001 ; Zhu et al 1999 ), and from single-colored probes to multiple-colored probes ( Tang et al 2009 ), have all been designed to optimize the probe detection sensitivity. Nowadays, FISH is a versatile and accurate tool for chromosome localization of sequences ( Gomez et al 1997 ), cytogenetic map construction ( Sun et al 2013 ; Han et al 2011 ; Cui et al 2015 ), genome structure study ( Zhao et al 2011 ; Wang et al 2001a ), genome evolution ( Wu et al 2013 ), and comparative genomics study ( Gan et al 2013 ).…”

Section: Introductionmentioning

confidence: 99%

Screening and chromosome localization of two cotton BAC clones

Cui

Liu

et al. 2016

CCG

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Two (BAC)bacterial artificial chromosome clones (350B21 and 299N22) of Pima 90-53 cotton [Gossypium barbadense Linnaeus, 1753 (2n=4x=52)] were screened from a BAC library using SSR markers. Strong hybridization signals were detected at terminal regions of all A genome (sub-genome) chromosomes, but were almost absent in D genome (sub-genome) chromosomes with BAC clone 350B21 as the probe. The results indicate that specific sequences, which only exist at the terminal parts of A genome (sub-genome) chromosomes with a huge repeat number, may be contained in BAC clone 350B21. When utilizing FISH with the BAC clone 299N22 as probe, a pair of obvious signals was detected on chromosome 13 of D genome (sub-genome), while strong dispersed signals were detected on all A genome (sub-genome) chromosomes. The results showed that peculiar repetitive sequence, which was distributed throughout all A genome (sub-genome) chromosomes, may exist in BAC clone 299N22. The absence of the repetitive sequences, which exist in the two BAC clones, in D genome may account for the genome-size variation between A and D genomes. In addition, the microcolinearity analysis of the clone 299N22 and its homologous region on Gossypium raimondii Ulbrich, 1932 chromosome 13 (D513) indicated that the clone 299N22 might come from A sub-genome of sea island cotton (Gossypium barbadense), and a huge number of small deletions, illegitimate recombination, translocation and rearrangements may have occurred during the genus evolution. The two BAC clones studied here can be used as cytological markers but will be also be helpful to research in cotton genome evolution and comparative genomics.

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“…The chromosome 7 of G. raimondii genome sequence is homologous to the chromosome 11 (here named as D11) of tetraploid cotton; the former was based on a genetic map (Rong et al, 2004;Paterson et al, 2012), and the latter is based on the physical chromosomes (Wang et al, 2006). A 45S rDNA signal is typically located at the telomeric region on D11 in G. raimondii on the basis of the study of Gan et al (2013). Theoretically, the chromosome 7-specific oligo developed from G. raimondii genome sequence should be collinear with one of 45S rDNA locus.…”

Section: Co-location With the Chromosome 7-specific Oligo And 45s Ribmentioning

confidence: 99%

“…Highly repeated 45S rDNA units are arranged in tandem at one or several chromosomal loci (Chang et al, 2010). In G. raimondii, the 45S rDNA was located at the terminal region of chromosomes D 5 02, D 5 09, and D 5 11 (corresponding to Chr.05, Chr.06, and Chr.07 of G. raimondii genome sequence map), which differ greatly with other D genome species (Gan et al, 2013). The sequence of ITS region (accession number U12718) amplified from G. raimondii (Wendel et al, 1995) had been used to blast against the G. raimondii genome sequence 1 .…”

Section: Introductionmentioning

confidence: 97%

Chromosome Painting Based on Bulked Oligonucleotides in Cotton

et al. 2020

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Chromosome painting is one of the key technologies in cytogenetic research, which can accurately identify chromosomes or chromosome regions. Oligonucleotide (oligo) probes designed based on genome sequences have both flexibility and specificity, which would be ideal probes for fluorescence in situ hybridization (FISH) analysis of genome structure. In this study, the bulked oligos of the two arms of chromosome seven of cotton were developed based on the genome sequence of Gossypium raimondii (DD, 2n = 2× = 26), and each arm contains 12,544 oligos. Chromosome seven was easily identified in both D genome and AD genome cotton species using the bulked chromosome-specific painting probes. Together with 45S ribosomal DNA (rDNA) probe, the chromosome-specific painting probe was also successfully used to correct the chromosomal localization of 45S rDNA in G. raimondii. The study reveals that bulked oligos specific to a chromosome is a useful tool for chromosome painting in cotton.

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Chromosomal Locations of 5S and 45S rDNA in Gossypium Genus and Its Phylogenetic Implications Revealed by FISH

Cited by 33 publications

References 42 publications

Variation in Genome Size, Ploidy, Stomata, and rDNA Signals in Althea

Variation in Genome Size, Ploidy, Stomata, and rDNA Signals in Althea

Screening and chromosome localization of two cotton BAC clones

Chromosome Painting Based on Bulked Oligonucleotides in Cotton

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