•Origanum species and subspecies were characterized by FCM and ISSR-PCR methods.•Origanum species/subspecies possessed very small genomes.•Genetic diversity in the genus have been described.•Genome ...size and ISSR markers are effective in Origanum species/subspecies identification.
The genus Origanum has the complex taxonomy and extensive genetic variation between species, mainly due to the presence of the significant morphological differences within plants and natural hybridization, even among distantly related species. This genus includes numerous species, subspecies, varieties and hybrids, what makes their characterization very complicated. Moreover, the existence of a large number of synonymous names makes the correct identification difficult. High degree of heterogeneity causes, that a potential for utilization of oregano has not been fully explored yet. Therefore, genome size and ISSR markers can be applied for identification and characterization of species from the Origanum genus. Genome size estimation revealed, that all Origanum species possessed very small genomes. The nuclear DNA content ranged from 1.45 pg/2C (O. vulgare) to 1.73 pg/2C (O. majorana). This is the first time the genome size have been estimated in O. heracleoticum, O. majorana, O. vulgare ssp. gracile, O. vulgare ssp. hirtum and O. vulgare ssp. vulgare. Based on the 2C-values it was possible to distinguish O. majorana from O. syriacum. For the discrimination of all accessions of Origanum genus, the ISSR markers were applied. Using primers: (GACA)4A, and (AG)8YA, it was possible to identify and distinguish species and subspecies. The relationships within tested accessions reflected by genetic distance estimation and dendrogram construction revealed the existence of two main clusters. The first cluster grouped all the accessions of O. vulgare, whereas two species, O. majorana and O. syriacum, were grouped into second cluster. The identification system composed of flow cytometry and ISSR-PCR technique demonstrated to be useful for genotypes in the Origanum genus.
The genome size and karyomorphology of six accessions of Limosella aquatica L. in Japan were investigated. All six accessions had a chromosome number of 2n=40. The genome size of L. aquatica was ...estimated using flow cytometry (FCM) and 2C of the tetraploid genome size ranged from 1.38 pg in accession Shiranuka to 1.42 pg in accession Taiki (1,178–1,216 Mbp), with 1Cx estimated to be ca. 0.35 pg (300 Mbp). The GC contents of all accessions were less than 40%. The centromeres of all chromosomes were located at median positions, while secondary constrictions were found at the distal regions of two chromosomes, resulting in small chromatin segments as satellites. The chromosome complement showed a monomodal karyotype with a gradual decrease in the chromosome length, ranging from 1.3 to 0.6 µm. The average chromosome lengths of accessions in Hokkaido and Honshu were 0.9 and 1.0 µm, respectively. The accessions in Kumamoto were exceptions, showing chromosome lengths ranging from 1.6 to 0.8 µm. The DNA base-specific banding revealed that the pericentromeric regions of all chromosomes and the satellites were chromomycin A3 positive and 4′,6-diamidino-2-phenylindole negative (CMA+DAPI−). The 18S rDNA fluorescence in situ hybridization (FISH) result also showed that the two signals were located at exactly the same positions as the CMA+DAPI− satellites.
Indirect somatic embryogenesis (ISE) is required for plant propagation and a prerequisite for applications that may provide new germplasms. Genetic, epigenetic and physiological features of the ...explant donor are barriers for ISE establishment, hindering its wide use. Despite the identification and/or expression analysis of genes during ISE, no approach to establish the karyotype aspects has been performed so far. So, this study aims to establish the ISE and compare the in vitro responses between diploid (
Coffea canephora
and
Coffea eugenioides
), allotriploid (“Híbrido de Timor”—HT) and true allotetraploid (
Coffea arabica
)
Coffea
in a taxonomic and evolutive scenario. Under the same in vitro conditions, the four
Coffea
differed from each other during ISE. Leaf explants of the true allopolyploids yielded the highest mean number of friable calli (FC) in relative short time and visually exhibiting more pronounced length. FC of the allotetraploid
C. arabica
presented the highest mean number of mature cotyledonary somatic embryos (MCSE), which were also recovered faster in this species. However, MCSE mean number in HT was the same or lower than diploid
Coffea
. Besides, intraspecific variation related to the ISE responses was observed in each
Coffea
, mainly the mean number of FC obtained from ex vitro and in vitro
C. arabica
and
C. eugenioides
explants. So, epigenetic and physiologic features may also have influenced the ISE responses. The findings provide the basis for performing other approaches considering the ploidy level, epigenetic and physiological backgrounds. Besides, the data also contributed for understanding about the consequences of polyploidy.
Breeding programs in ornamentals can be facilitated by integrating knowledge of phylogenetic relatedness of potential parents along with other genomic information. Using AFLP, genetic distances were ...determined for 59 Geranium genotypes, comprising 55 commercial cultivars of the three subgenera of a total collection of 61 Geranium genotypes. A subgroup of 45 genotypes, including intragroup and intergroup hybrids, were selected and further characterized for genome sizes and chromosome numbers. The variation in genome size ranged from 1.51 ± 0.01 pg/2C to 12.94 ± 0.07 pg/2C. The chromosome numbers ranged from 26 to 108–110 with some hybrids showing an aberrant number of chromosomes based on their parents’ constitution. All chromosome numbers of Geranium are an even number, which presumes that unreduced gametes occur in some cross combinations. Overall, parental difference in genome size and chromosome number were not limiting for cross compatibility. Good crossing compatibility was correlated to a Jaccard similarity coefficient as parameter for parental relatedness of about 0.5. Additionally, parent combinations with high differences in the DNA/chromosome value could not result in a successful cross. We expect that our results will enable breeding programs to overcome crossing barriers and support further breeding initiatives.
In this work, we investigated the chromosome number and genome size of two Mediterranean Amaranthaceae species, namely
Atriplex mollis
from southern Tunisia and
A. lanfrancoi
(formerly
Cremnophyton ...lanfrancoi
) from Malta. The two species were found to be diploid (2
n
= 18) for all examined populations. This result is different from that previously reported for
Cremnophyton lanfrancoi
Brullo and Pavone (2
n
= 20). Genome size showed that both species have a close mean amount with 2
C
= 3.41 and 3.51 pg, respectively. Two groups were distinguished with regard to genome size (
P
< 0.01). It should, however, be noted that the majority of populations, with the exception of those from Djerba and Chbika, may be intermediate between the two basic groups. Moreover, the difference does not appear to depend on geographical distribution and environmental aspects. It would rather depend on chromosome rearrangements. The morphological similarities, the monophyly of
Atriplex
including
A. lanfrancoi
, previously ranked in genus
Cremnophyton
, sharing the same chromosome number and the same genome size, support the placement of
Cremnophyton
within the genus
Atriplex.
It is generally accepted that polyploids have downsized basic genomes rather than additive values with respect to their related diploids. Changes in genome size have been reported in correlation with ...several biological characteristics. About 75 % of around 350 species recognized for
Paspalum
(Poaceae) are polyploid and most polyploids are apomictic. Multiploid species are common with most of them bearing sexual diploid and apomictic tetraploid or other ploidy levels. DNA content in the embryo and the endosperm was measured by flow cytometry in a seed-by-seed analysis of 47 species including 77 different entities. The relative DNA content of the embryo informed the genome size of the accession while the embryo:endosperm ratio of DNA content revealed its reproductive mode. The genome sizes (2C-value) varied from 0.5 to 6.5 pg and for 29 species were measured for the first time. Flow cytometry provided new information on the reproductive mode for 12 species and one botanical variety and supplied new data for 10 species concerning cytotypes reported for the first time. There was no significant difference between the mean basic genome sizes (1Cx-values) of 32 sexual and 45 apomictic entities. Seventeen entities were diploid and 60 were polyploids with different degrees. There were no clear patterns of changes in 1Cx-values due to polyploidy or reproductive systems, and the existing variations are in concordance with subgeneric taxonomical grouping.
Knowledge of genetic identity, genetic relationships, ploidy level, and chromosome numbers can enhance the efficiency of ornamental plant breeding programs. In the present study, genome sizes, ...chromosome numbers, and genetic fingerprints were determined for a collection of 94 Ilex accessions, including 69 I. crenata. The genome size of the entire collection ranged from 1.50 ± 0.03 to 8.01 ± 0.18. Within the species of I. crenata, genome sizes varied (mean ± sd) between 1.98 ± 0.08 and 2.30 ± 0.04, with three outliers: 3.06 ± 0.04, 4.04 ± 0.09, and 4.19 ± 0.08. The chromosome counting results showed 2n = 40 for I. crenata accessions and confirmed the outliers as one triploid and two tetraploids. A high intra-specific genetic diversity in Ilex crenata was found, after genetic fingerprinting using genotyping-by-sequencing (GBS). The species I. crenata was separated into three clades, which coincided with intraspecific differences in genome sizes (mean ± sd) of 2.09 ± 0.006, 2.07 ± 0.05, and 2.19 ± 0.06 pg/2C per clade as mean values for the diploids. Applying a principal coordinate analysis (PCoA) to the genetic fingerprinting data of all species in the collection revealed a wide genetic variation, which has not yet been commercially exploited. These findings could form the basis for selectively breeding parents, in order to create more genetic diversity via intra- and interspecific crosses.
Chromosomal and karyotype parameters and genome size were examined in 22 Iranian populations of nine different Tulipa species, using squash technique and 1 % (w/v) aceto-orcein stain. Flow cytometric ...studies were performed using PI staining method and Vicia faba cv. Inovec (2C DNA = 26.9 pg) as a reference standard. Most species were diploid (2n = 2x = 24), having three chromosome types (“m”, “sm”, “st”). The chromosome length (TL) varied from 6.4 μm (S2) to 12.90 μm (S3). Total chromosome volume (TCV) ranged from 32.9 μm³(S2) to 66.0 μm³(S8). Statistical analyses confirmed more intraspecific chromosomal and genome size variations than interspecific. S1E2, S2E1 and S5E2, with the highest intrachromosomal (MCA) and relatively high interchromosomal asymmetry (CVCL), indicated higher asymmetry in the karyotype. The genome size in Tulipa species of Iran is being reported for the fist time. The mean 2C DNA was 54.52 pg, and ranged from 77.40 in S6E2 to 31.51 pg in S9E2. Significant positive correlations were found between 2C DNA and either TL or TCV.
Genome size determination by a flow cytometry (FCM) and chromosome characterization by fluorescent banding, including fluorescence in situ hybridization (FISH), were employed for cytogenetic analysis ...of two important marigold species, Tagetes erecta (African marigold) and T. patula (French marigold). The FCM data showed that T. erecta had a 2C value of 1.43 pg, while T. patula had a 2C value of 2.54 pg, showing 2-times difference in genome size. Somatic chromosome number was 2n=24 in T. erecta, while the number was 2n=48 in T. patula, indicating arise out of a chromosome doubling event. Chromomycin A3 (CMA) and 4′,6-diamidino-2-phenylindole (DAPI) bands were recognized at different positions on all chromosomes in Tagetes genome, making possible chromosome identification by fluorescent band pattern, especially in T. erecta. FISH results showed that clear telomere signals appeared at both ends of all chromosomes and eight weak 45 rDNA signals on the terminal and middle sites on certain chromosomes in diploid species T. erecta.
section
is one of the important characteristic elements of thorn-cushion formations in the Irano-Turanian floristic region. In this paper, we examined the chromosome number of 17 species (15 new ...reports) and provide estimates of genome size for 62 individuals belonging to 38 taxa of
sect.
, some species outside this section, plus two
species. Based on chromosome counts 11 species were found to be diploid (2
= 16), four species tetraploid (2
= 32) and two taxa hexaploid (2
= 48). From genome size measurements on silica-gel dried material, three ploidy levels (2
, 4
and 6
) were inferred, with a majority of species being diploid. The 2C values reach from 2.07 pg in diploid
to 7.16 pg in hexaploid
.
. We found indications that species might occur with different cytotypes. A phylogenetic framework using nrDNA ITS sequences was constructed to understand the evolution of ploidy changes and genome sizes. It showed that genome size values among the studied taxa differ only slightly within ploidy levels and are nearly constant within most species and groups of closely related taxa within the genus
. The results of this study show that there is a rather strong correlation between genome sizes and chromosome numbers in sect.
. The resolution of the ITS-based phylogenetic tree is too low to infer evolutionary or environmental correlations of genome size differences. Polyploidization seems to contribute to the high species number in
, however, in sect.
it is not the main driver of speciation.
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