Genome Size, Chromosome Number and Morphological Data Reveal Unexpected Infraspecific Variability in Festuca (Poaceae)

Polyploidy has played an important evolutionary role in the genus Festuca (Poaceae), and several ploidy levels (ranging from 2n = 2x = 14 to 2n = 12x = 84) have been detected to date. This study aimed to estimate the genome size and ploidy level of two subspecies belonging to the F. yvesii polyploid complex by flow cytometry and chromosome counting. The phenotypic variation of the cytotypes was also explored, based on herbarium material. The genome size of F. yvesii subsp. lagascae has been estimated for the first time. Nuclear 2C DNA content of F. yvesii subsp. summilusitana ranged from 21.44 to 31.91 pg, while that of F. yvesii subsp. lagascae was from 13.60 to 22.31 pg. We report the highest ploidy level detected for Festuca (2n = 14x = 98) and previously unknown cytotypes. A positive correlation between holoploid genome size and chromosome number counts shown herein was confirmed. The morphometric approach showed a slight trend towards an increase in the size of some organs consistent with the variation in the ploidy level. Differences in characters were usually significant only among the most extreme cytotypes of each subspecies, but, even in this case, the high overlapping ranges prevent their distinction.

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Genome size, chromosome number, and rDNA organisation in Algerian populations of Artemisia herba-alba (Asteraceae), a basic plant for animal feeding facing overgrazing erosion

Anales del Jardín Botánico de Madrid ◽

10.3989/ajbm.2415 ◽

2016 ◽

Vol 73 (2) ◽

pp. 043

Author(s):

Youcef Bougoutaia ◽

Sònia Garcia ◽

Teresa Garnatje ◽

Meriem Kaid-Harche ◽

Joan Vallès

Keyword(s):

Chromosome Number ◽

Genome Size ◽

In Situ Hybridisation ◽

Fluorescence In Situ Hybridisation ◽

Ploidy Levels ◽

Rdna Genes ◽

Basic Plant ◽

Tetraploid Cytotypes ◽

First Time

Artemisia herba-alba is a largely-distributed and often landscape-dominating taxon in arid areas of the Mediterranean and Irano-Turanian regions. In Algeria, in 2010 its communities covered 10% of the steppe territory, but its populations have been subjected to overgrazing. A karyological study based on 22 populations together with a cytogenetic characterisation of this species has been performed for the first time in Algerian materials, through genome size and chromosome number determination. Fluorescence in situ hybridisation (FISH) was also used to assess the rDNA loci number and distribution in the two ploidy levels detected. The studied accessions are diploid (2n = 2x = 18 chromosomes, 6 populations) or tetraploid (2n = 4x = 36 chromosomes, 15 populations). One population, occupying a more or less central geographic position among the studied area, presented both cytotypes. Genome size reflects well the two ploidy levels, with no evidence of downsizing with polyploidy. The karyotypes are rather symmetric (2A Stebbins’ class). FISH analyses detected four signals (2 loci) in diploid and eight signals (4 loci) in tetraploid cytotypes for both ribosomal DNA genes, which present an L-type (linked) organisation, i.e. with loci from both rDNA genes colocalised. The presence of two ploidy levels suggest a genomic dynamism and even a possible differentiation underlying the morphological uniformity and despite the dramatic decrease experienced by this plant in Algeria in terms of surface coverage.

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Genome size variation and karyotype diversity in eight taxa of Sorbus sensu stricto (Rosaceae) from China

Comparative Cytogenetics ◽

10.3897/compcytogen.v15i2.58278 ◽

2021 ◽

Vol 15 (2) ◽

pp. 137-148

Author(s):

Jiabao Li ◽

Kailin Zhu ◽

Qin Wang ◽

Xin Chen

Keyword(s):

Flow Cytometry ◽

Genome Size ◽

Size Variation ◽

Sensu Stricto ◽

Chromosome Size ◽

Chromosome Counting ◽

Genome Size Variation ◽

Ploidy Levels ◽

First Time ◽

Karyotype Symmetry

Eight taxa of Sorbus Linnaeus, 1753 sensu stricto (Rosaceae) from China have been studied karyologically through chromosome counting, chromosomal measurement and karyotype symmetry. Genome size was also estimated by flow cytometry. Six taxa, S. amabilis Cheng ex T.T.Yu et K.C.Kuan, 1963, S. hupehensis var. paucijuga (D.K. Zang et P.C. Huang, 1992) L.T. Lu, 2000, S. koehneana C.K. Schneider, 1906, S. pohuashanensis (Hance, 1875) Hedlund, 1901, S. scalaris Koehne, 1913 and S. wilsoniana C.K. Schneider, 1906 are diploids with 2n = 34, whereas two taxa, S. filipes Handel-Mazzetti,1933 and S. ovalis McAllister, 2005 are tetraploid with 2n = 68. In general, the chromosome size is mainly small, and karyotypes are symmetrical with predominance of metacentric chromosomes. Genome size variation of diploids and tetraploids is 1.401 pg –1.676 pg and 2.674 pg –2.684 pg, respectively. Chromosome numbers of S. amabilis and S. hupehensis var. paucijuga, and karyotype and genome size of eight taxa studied are reported for the first time. This study emphasised the reliability of flow cytometry in genome size determination to infer ploidy levels in Chinese native Sorbus species.

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Identification, Genome Sizes, and Ploidy of Deutzia

Journal of the American Society for Horticultural Science ◽

10.21273/jashs04779-19 ◽

2020 ◽

Vol 145 (2) ◽

pp. 88-94

Author(s):

William G. Hembree ◽

Thomas G. Ranney ◽

Nathan P. Lynch ◽

Brian E. Jackson

Keyword(s):

Flow Cytometry ◽

Genome Size ◽

Ploidy Level ◽

State University ◽

Ploidy Levels ◽

Specific Data ◽

North Carolina State University ◽

The North ◽

Voucher Specimens ◽

First Time

The genus Deutzia, in the Hydrangeaceae family, includes ≈60 species that range in ploidy from diploid (2x) to tetradecaploid (14x). There have been extensive breeding efforts for Deutzia, but this has been limited to a few parental species. Although there have been numerous studies of the cytogenetics of some species of Deutzia, the ploidy level of many species remains unknown, and there are few cytogenetic data available for Deutzia hybrids and cultivars. The purpose of this study was to validate the identification and determine the genome sizes and ploidy of a diverse collection of Deutzia species and hybrids using cytology and flow cytometry. Accessions were identified using the most current taxonomic key and voucher specimens were deposited for each at the North Carolina State University herbarium. Corrected and updated species names are provided for all cultivars and accessions studied. Traditional cytology was performed for roots of representative taxa to calibrate the genome size with the ploidy level. The genome size and estimated ploidy were determined for 43 accessions using flow cytometry. Ploidy levels were reported for the first time for three species of Deutzia including D. calycosa (2n = 4x = 52), D. paniculata (2n = 4x = 52), and D. glauca (2n = 12x = 156). The base and monoploid genome size (1Cx) were somewhat variable and ranged from 1.20 to 2.05 pg. No anisoploid hybrids were documented, suggesting the presence of an interploid block. The information produced from this study are beneficial to future curation, research, development, and improvement of this genus with corrected nomenclature and clone-specific data regarding cytogenetics.

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Genome size variation and karyotype diversity in eight taxa of Sorbus sensu stricto (Rosaceae) from China

Comparative Cytogenetics ◽

10.3897/compcytogen.v15.i2.58278 ◽

2021 ◽

Vol 15 (2) ◽

pp. 137-148

Author(s):

Jiabao Li ◽

Kailin Zhu ◽

Qin Wang ◽

Xin Chen

Keyword(s):

Flow Cytometry ◽

Genome Size ◽

Size Variation ◽

Sensu Stricto ◽

Chromosome Size ◽

Chromosome Counting ◽

Genome Size Variation ◽

Ploidy Levels ◽

First Time ◽

Karyotype Symmetry

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Chromosome studies on African plants. 9. Chromosome numbers in Ehrharta (Poaceae: Ehrharteae)

Bothalia ◽

10.4102/abc.v19i1.948 ◽

1989 ◽

Vol 19 (1) ◽

pp. 125-132 ◽

Cited By ~ 2

Author(s):

J. J. Spies ◽

E. J. L. Saayman ◽

S. P. Voges ◽

G. Davidse

Keyword(s):

Chromosome Number ◽

Ploidy Level ◽

Chromosome Numbers ◽

Basic Chromosome Number ◽

B Chromosomes ◽

Basic Chromosome ◽

Cytogenetic Studies ◽

African Plants ◽

First Time

Cytogenetic studies of 53 specimens of 14 species of the genus Ehrharta Thunb. confirmed a basic chromosome number of 12 for the genus. Chromosome numbers for 13 species are described for the first time. The highest ploidy level yet observed in the genus (2n = lOx = 120) is reported for E. villosa var. villosa. B chromosomes were observed in several specimens of four different species.

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A cytotaxonomic survey of the Pteridophyta of Australia

Australian Systematic Botany ◽

10.1071/sb00034 ◽

2002 ◽

Vol 15 (6) ◽

pp. 839 ◽

Cited By ~ 34

Author(s):

Mary D. Tindale ◽

S. K. Roy

Keyword(s):

Ploidy Level ◽

New Combination ◽

Chromosome Counts ◽

Ploidy Levels ◽

Australian Species ◽

Number Of Species ◽

Lord Howe Island ◽

Species Complexes ◽

Living Material ◽

First Time

A cytotaxonomic survey of the ferns and fern allies of Australia (including Lord Howe Island) is presented. Five-hundred-and-twenty-six chromosome counts of 268 Australian species, subspecies, varieties, variants and hybrids are recorded, only a small number having been previously investigated by other botanists on Australian material. Diploids represent c. 62% of the counts on species and c. 38% on polyploids, the latter ranging principally from triploids to a single decaploid and dodecaploid (but no heptaploids). More than one ploidy level has been reported in 19 taxa (almost 8% of taxa). Counts of 10x for Asplenium aethiopicum and 12x for A.�flabellifolium are the highest definite ploidy levels for the Australian pteridophyte flora. Chromosome counts for 29 families and 89 genera are cited. Only diploids were reported for Osmundaceae and Cyatheaceae, but only polyploids for the Psilotaceae, Vittariaceae and Ophioglossaceae. An analysis is given of the levels of ploidy in 248 taxa, excluding the Lycopodiaceae and Hymenophyllaceae. The percentages of diploids and polyploids in Australian species are compared with those of nearby countries. Many species reported on here have never been cytologically investigated before, while others have not been studied previously on Australian material. The following genera have been examined cytologically for the first time: Coveniella Tindale, n = 41; Paraceterach (F.Muell.) Copel., n = 29; 'Oenotrichia Copel.', 2n = 82 (2x); Revwattsia (Watts) D.L.Jones, 2n = c. 328 (8x); and Pteridoblechnum Hennipman (2n = 54). The phylogeny of the genera is discussed in the light of these findings. Certain families such as the Adiantaceae, Cyatheaceae, Hymenophyllaceae, Lindsaeaceae and Marsileaceae were given special attention by collecting as much living material as possible. A number of species-complexes has been found and further chromosome counts added to intercontinental species complexes. The Döpp-Manton and Braithwaite forms of reproductive apomixis have been reported amongst some genera. Endemism, hybridity and apogamy amongst Australian pteridophytes are discussed, as well as homosporous and heterosporous species. The new combination Phymatosorus membranifolius (R.Br.) Tindale is made.

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Chromosome Number, Ploidy Level, and Nuclear DNA Content in 23 Species of Echeveria (Crassulaceae)

Genes ◽

10.3390/genes12121950 ◽

2021 ◽

Vol 12 (12) ◽

pp. 1950

Author(s):

Guadalupe Palomino ◽

Javier Martínez-Ramón ◽

Verónica Cepeda-Cornejo ◽

Miriam Ladd-Otero ◽

Patricia Romero ◽

...

Keyword(s):

Flow Cytometry ◽

Chromosome Number ◽

Ploidy Level ◽

Dna Content ◽

Chromosome Numbers ◽

Nuclear Dna ◽

Nuclear Dna Content ◽

Root Tips ◽

Ploidy Levels ◽

Dna Amounts

Echeveria is a polyploid genus with a wide diversity of species and morphologies. The number of species registered for Echeveria is approximately 170; many of them are native to Mexico. This genus is of special interest in cytogenetic research because it has a variety of chromosome numbers and ploidy levels. Additionally, there are no studies concerning nuclear DNA content and the extent of endopolyploidy. This work aims to investigate the cytogenetic characteristics of 23 species of Echeveria collected in 9 states of Mexico, analyzing 2n chromosome numbers, ploidy level, nuclear DNA content, and endopolyploidy levels. Chromosome numbers were obtained from root tips. DNA content was obtained from the leaf parenchyma, which was processed according to the two-step protocol with Otto solutions and propidium iodide as fluorochrome, and then analyzed by flow cytometry. From the 23 species of Echeveria analyzed, 16 species lacked previous reports of 2n chromosome numbers. The 2n chromosome numbers found and analyzed in this research for Echeveria species ranged from 24 to 270. The range of 2C nuclear DNA amounts ranged from 1.26 pg in E. catorce to 7.70 pg in E. roseiflora, while the 1C values were 616 Mbp and 753 Mbp, respectively, for the same species. However, differences in the level of endopolyploidy nuclei were found, corresponding to 4 endocycles (8C, 16C, 32C and 64C) in E. olivacea, E. catorce, E. juarezensis and E. perezcalixii. In contrast, E. longiflora presented 3 endocycles (8C, 16C and 32C) and E. roseiflora presented 2 endocycles (8C and 16C). It has been suggested that polyploidization and diploidization processes, together with the presence of endopolyploidy, allowed Echeveria species to adapt and colonize new adverse environments.

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Chromosome counts of eight Iranian endemic species of Nepeta L. (Lamiaceae)

Caryologia ◽

10.36253/caryologia-729 ◽

2021 ◽

Vol 74 (1) ◽

pp. 53-61

Author(s):

Maryam Hasaninejad ◽

Ziba Jamzad ◽

Saeid Afsharzadeh ◽

HojJatollah Saeidi

Keyword(s):

Chromosome Number ◽

Species Group ◽

Chromosome Length ◽

Basic Chromosome Number ◽

Chromosome Counts ◽

Ploidy Levels ◽

Study Results ◽

Karyotypic Diversity ◽

Karyotype Formula ◽

First Time

In this survey, the chromosome counts of eight Nepeta L. species were investigated and the karyotypic diversity among these species was studied. The examined species belong to N. cephalotes Boiss. species group, namely N. eremokosmos Rech.f., N. gloeocephala Rech. f., cephalotes Boiss., N. pungens (Bunge) Benth., N. ispahanica Boiss., N. mahanensis Jamzad & Simonds, N. hormozganica Jamzad and N. denudata Benth. collected from different habitats in Iran. The ploidy levels, karyotype formula, chromosome length range, total karyotype length, several karyotype asymmetries values and Stebbins classification were determined in this study. Results showed the same chromosome number, 2n = 2x= 18 for all studied species. The basic chromosome number for the above mentioned species are x = 9. Also, the smallest chromosome length is 1.02 μm in N. mahanensis. The largest chromosome length is 2.3 μm in N. ispahanica. The chromosomes of species were metacentric or submetacentric. According to the Stebbins classification, these species were located into three classes 1A, 2A and 3A. The chromosome numbers for six of studied species are reported here for the first time.

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The contrasting effects of genome size, chromosome number and ploidy level on plant invasiveness: a global analysis

New Phytologist ◽

10.1111/nph.12799 ◽

2014 ◽

Vol 203 (2) ◽

pp. 697-703 ◽

Cited By ~ 66

Author(s):

Maharaj K. Pandit ◽

Steven M. White ◽

Michael J. O. Pocock

Keyword(s):

Chromosome Number ◽

Genome Size ◽

Ploidy Level ◽

Global Analysis ◽

Plant Invasiveness

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The influence of cell size and chromosome dosage on cold-hardiness expression in the Triticeae

Genome ◽

10.1139/g89-496 ◽

1989 ◽

Vol 32 (4) ◽

pp. 667-671 ◽

Cited By ~ 17

Author(s):

A. E. Limin ◽

D. B. Fowler

Keyword(s):

Chromosome Number ◽

Cell Size ◽

Common Wheat ◽

Ploidy Level ◽

Guard Cell ◽

Cold Hardiness ◽

Gene Dosage ◽

Large Cell ◽

Gene Dosage Effect ◽

Ploidy Levels

The influence of cell size and chromosome dosage on cold-hardiness expression was investigated in members of the tribe Triticeae. Mean leaf guard-cell lengths for ploidy levels of 2x, 4x, 6x, and 8x were found to increase by approximately 10 μm with each addition of two basic (x = 7) genomes, indicating that larger cell size was associated with higher ploidy level. Poor expression of cold hardiness in amphiploids was associated with large cell size. However, comparisons among and within species indicated that ploidy level was not the only factor determining cell size. Significant differences in guard-cell length were observed among common wheat (Triticum aestivum L. em. Thell.) cultivars. Cell size differences among cultivars were found in both hardened and nonhardened common wheat plants and these differences were associated with cultivar cold hardiness (r = 0.95, P ≤ 0.01). The evidence indicated that smaller cell size influenced cold tolerance by amplifying the expression of cold-hardiness genes in cold-acclimated plants, probably by reducing the degree of cell contraction from freeze dehydration. A chromosome (gene) dosage effect that favored the expression of genes from the parent species contributing the higher chromosome number was also shown to play an important role in the expression of cold hardiness in interspecific hybrids and amphiploids. Comparison of related species with similar cell size and chromosome number suggested differences in the effectiveness of cold hardiness conferring genes. Observations made on species from the Triticeae indicate that when cold-hardiness potential is limited at the diploid level, a plant group may expand its cold-hardiness range by "loading up" on existing cold-hardiness genes by means of polyploidy. An increased genetic potential may then be further enhanced by selection for smaller cell size within the polyploid nucleotype. This process appears to have been responsible for the superior cold hardiness of hexaploids within the Triticum genus.Key words: cell size, cold hardiness, gene dosage, Triticeae, evolution, interspecific hybrid, Agropyron.

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