Genome size variation in Deschampsia cespitosa sensu lato (Poaceae) in Eurasia

The grass Deschampsia cespitosa is a variable taxon out of which many varieties, subspecies and endemic species have been separated. In this paper, the variation in genome size (GS) and ploidy of this grass including several of its subspecies and two related species in Eurasia was investigated by flow cytometric (FCM) measurements. GS and ploidy data were also related to specific environments and reproduction mode. Ploidy levels found by FCM were confirmed by chromosome counts of diploid (2n = 28) and tetraploid (2n = 52) samples. Seminiferous (seed bearing) D. cespitosa was mainly diploid (GS between 3.754 and 5.438 pg/1C). GS variation in diploids showed a geographic pattern with a significant difference (H = 41,441, P < 0.001) between European (median = 4.377 pg) and Asian (median = 4.881 pg) accessions. Genome size (1C) in tetraploids ranged from 7.9426 to 9.0399 pg. Tetraploid seminiferous D. cespitosa was found mostly in disturbed habitats in western and southern Europe, while tetraploids in Asia were registered in wet Arctic habitats. Genome size (1C between 8.3278 and 8.8603 pg) of the pseudoviviparous plants (spikelets produce plantlets asexually) of wet habitats in central and northern Europe indicated tetraploidy. A putative triploid (GS 6.6817 pg) was detected in Iceland. Summing up, we found a high variation in GS on the geographic scale with significant regional differences in diploid D. cespitosa. Among the tetraploids, the asexually reproducing plants were bound to specific habitats, while the seminiferous plants showed a habitat preference similar to the diploids.

Know your enemy: Application of ATR-FTIR spectroscopy to invasive species control

Extreme weather and globalisation leave our climate vulnerable to invasion by alien species, which have negative impacts on the economy, biodiversity, and ecosystem services. Rapid and accurate identification is key to the control of invasive alien species. However, visually similar species hinder conservation efforts, for example hybrids within the Japanese Knotweed complex. We applied the novel method of ATR-FTIR spectroscopy combined with chemometrics (mathematics applied to chemical data) to historic herbarium samples, taking 1580 spectra in total. Samples included five species from within the interbreeding Japanese Knotweed complex (including three varieties of Japanese Knotweed), six hybrids and five species from the wider Polygonaceae family. Spectral data from herbarium specimens were analysed with several chemometric techniques: support vector machines (SVM) for differentiation between plant types, supported by ploidy levels; principal component analysis loadings and spectral biomarkers to explore differences between the highly invasive Reynoutria japonica var. japonica and its non-invasive counterpart Reynoutria japonica var. compacta; hierarchical cluster analysis (HCA) to investigate the relationship between plants within the Polygonaceae family, of the Fallopia, Reynoutria, Rumex and Fagopyrum genera. ATR-FTIR spectroscopy coupled with SVM successfully differentiated between plant type, leaf surface and geographical location, even in herbarium samples of varying age. Differences between Reynoutria japonica var. japonica and Reynoutria japonica var. compacta included the presence of two polysaccharides, glucomannan and xyloglucan, at higher concentrations in Reynoutria japonica var. japonica than Reynoutria japonica var. compacta. HCA analysis indicated that potential genetic linkages are sometimes masked by environmental factors; an effect that can either be reduced or encouraged by altering the input parameters. Entering the absorbance values for key wavenumbers, previously highlighted by principal component analysis loadings, favours linkages in the resultant HCA dendrogram corresponding to expected genetic relationships, whilst environmental associations are encouraged using the spectral fingerprint region. The ability to distinguish between closely related interbreeding species and hybrids, based on their spectral signature, raises the possibility of using this approach for determining the origin of Japanese knotweed infestations in legal cases where the clonal nature of plants currently makes this difficult and for the targeted control of species and hybrids. These techniques also provide a new method for supporting biogeographical studies.

How Cold Shock Affects Ploidy Level and Early Ontogenetic Development of the Sterlet, A. ruthenus L.

The objective of the present research was to study the effect of cold shock (3 °C and 6 °C) on fertilized eggs of the sterlet, Acipenser ruthenus L. Cold shock was applied for various durations (30, 60 and 90 min) and the ploidy levels, survival, and genotypes of the treated embryos/larvae were recorded. Analysis of ploidy levels confirmed the presence of diploid, triploid, and mosaic (1n/2n, 2n/3n, and 1n/2n/3n) genotypes in experimental groups, while it was strictly diploid in control groups. Microsatellite genotyping confirmed both the incidence of polyspermy and retention of the 2nd polar body in experimental groups. However, patterns of inheritance in all diploid offspring in experimental and control groups revealed classical Mendelian disomic inheritance. Interestingly, the observed mosaic sterlets had normal morphology and were alive. However, some larvae had abnormal morphology which may be due to haploid syndrome. In all treatment groups (treatments: 3 °C–30 min; 3 °C–60 min; 3 °C–90 min; 6 °C–60 min), where the percentage of polyploid/mosaic larvae were high, the mortality was also high. Whereas, in the control groups (where there were only diploid (2n) larvae), the mortality was relatively low.

Relationships among blueberry species within the section Cyanococcus of the Vaccinium genus based on EST-PCR markers

Commercial blueberry species of North America belong to the Vaccinium genus, section Cyanococcus. Phylogenetic relationships of 50 accessions of different ploidy levels within Cyanococcus were investigated using 249 expressed sequence tag-polymerase chain reaction markers and standard clustering methods. Of the commercial species, tetraploid V. corymbosum grouped most closely with the diploids, V. fuscatum and V. caesariense, followed by the diploid V. elliottii. Tetraploid V. angustifolium grouped with the diploids, V. boreale and V. myrtilloides. Hexaploid V. virgatum grouped most closely with the diploid V. tenellum, thus shedding light on the origins of these polyploid species.

Determination of Genome Size Differentiation and Ploidy Levels in Some Citrus Rootstock Populations

In plants, knowing the ploidy level of plant material used in breeding studies, and especially for biotechnology applications, carries great importance. The presence of a rapid variety of dynamics in citrus fruits allows their use as rootstock and varieties ensuring adaptability to various climate and soil conditions with different breeding methods. A variety of appropriate rootstocks are used for commercial citrus species. This study investigated the genome sizes and ploidy levels in citrus rootstocks commonly used around the world with flow cytometry in seedling populations. The study used Gou-Tou, C-35, Troyer Citrange, Taiwanica, Citremon, Yuzu, Sunki mandarin, Flying Dragon, Yuma Citrange, Macrophylla and Chinese orange rootstocks. Fresh leaf tissues were mixed with the triploid Tahiti lime leaf tissue, used as standard species, and cell nuclei were isolated. Cells stained with propidium iodide were read with flow cytometry and histograms and cytograms were obtained. According to the obtained results, all seedlings of species had diploid genome volumes. In terms of genome volume, there were differences found between species. Yuzu seedlings were determined to be the species with largest genome volume (0.808 pg/2C), while Flying Dragon trifoliate had smallest genome volume (0.700 pg/2C).

Characteristics of SP600125 Induced Tetraploid Cells in Comparison With Diploid and Tetraploid Cells of Fish

In our previous research, SP600125 (Anthrapyrazolone) was used to induce autotetraploid of crucian carp cells (SP4N cells), and tetraploid fry was generated from the SP4N cells by somatic cell nuclear transfer technique. However, it is still unclear about biological characteristics of the SP4N cells. In this article, the cytological characteristic and gene expression profiles of the SP4N cells are investigated in comparison with the crucian carp cells (2N cells) and the tetraploid crucian carp cells (CC4N cells). The SP4N cells have tetraploid characteristics in terms of morphology and DNA ploidy levels, and their chromosome behavior is stable during the cell proliferation. The migration ability and the mtDNA copy number of SP4N cells are both lower than those in the CC4N cells and the 2N cells, but there exist giant mitochondria in the SP4N cells. The similar expression trends in the cell cycle regulation genes of the SP4N cells and 2N cells, while the corresponding expression profiles are clearly different between the SP4N cells and the CC4N cells. Moreover, the significant difference genes are associated with energy metabolism pathways among the SP4N cells, 2N cells and CC4N cells. These results can provide deeper understanding of SP600125 induction, as well as finding applications in polyploidization breeding of fish species.

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

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.

Ploidy dynamics in aphid host cells harboring bacterial symbionts

Aphids have evolved bacteriocytes or symbiotic host cells that harbor the obligate mutualistic bacterium Buchnera aphidicola. Because of the large cell size (approximately 100 μm in diameter) of bacteriocytes and their pivotal role in nutritional symbiosis, researchers have considered that these cells are highly polyploid and assumed that bacteriocyte polyploidy may be essential for the symbiotic relationship between the aphid and the bacterium. However, little is known about the ploidy levels and dynamics of aphid bacteriocytes. Here, we quantitatively analyzed the ploidy levels in the bacteriocytes of the pea-aphid Acyrthosiphon pisum. Image-based fluorometry revealed the hyper polyploidy of the bacteriocytes ranging from 16- to 256-ploidy throughout the lifecycle. Bacteriocytes of adult parthenogenetic viviparous females were mainly 64-128C DNA levels, while those of sexual morphs (oviparous females and males) were consisted of 64C, and 32-64C cells, respectively. During post-embryonic development of viviparous females, the ploidy level of bacteriocytes increased substantially, from 16-32C at birth to 128-256C in actively reproducing adults. These results suggest that the ploidy levels are dynamically regulated among phenotypes and during development. Our comprehensive and quantitative data provides a foundation for future studies to understand the functional roles and biological significance of the polyploidy of insect bacteriocytes.

Short-term changes related to autotetraploidy in essential oil composition of Eucalyptus benthamii Maiden & Cambage and its applications in different bioassays

Some forest trees have been polyploidized to improve their traits and to supply new germplasms for breeding programs. As trees have a long juvenile stage, the early characterization of the chromosome set doubling effects is crucial for previous selection. Thus, we aimed to characterize the chemical variability of essential oils from diploid and autotetraploid germplasms (autotetraploid A and B) of Eucalyptus benthamii, as well as to evaluate their larvicidal and allelopathic effects. Autotetraploid A showed a higher essential oil yield than diploid and autotetraploid B, which did not differ quantitatively. Aromadendrene, viridiflorol and α-pinene were the major compounds in the diploid essential oil. In contrast, compounds were present in autotetraploids, such as 1,8-cineole, limonene, α-terpineol, and α-terpinyl-acetate. Essential oils from the diploid at 50–200 ppm were twice as larvicidal than those from autotetraploids against Aedes aegypti larvae. Considering the phytotoxicity bioassays using Lactuca sativa, essential oils from both ploidy levels affected root growth. Moreover, the essential oils inhibited shoot growth at all concentrations tested (187.5; 375; 750; 1500; and 3000 ppm). Autotetraploid A and B had the same effect on shoot growth as glyphosate. The essential oils had no cytogenotoxic effect on root meristematic cells of L. sativa, whereas phytotoxic potential was identified mainly in shoot growth. This work demonstrated a dramatic change in secondary metabolism (terpene composition) related to an increase in the ploidy level in Eucalyptus germplasms. In addition, we report the novelty of the chemical composition of essential oils among germplasms and their potential use as larvicidal and post-emergence weed control agents.

Genome-Wide Analysis of MYB10 Transcription Factor in Fragaria and Identification of QTLs Associated with Fruit Color in Octoploid Strawberry

The genus Fragaria encompass fruits with diverse colors influenced by the distribution and accumulation of anthocyanin. Particularly, the fruit colors of strawberries with different ploidy levels are determined by expression and natural variations in the vital structural and regulatory genes involved in the anthocyanin pathway. Among the regulatory genes, MYB10 transcription factor is crucial for the expression of structural genes in the anthocyanin pathway. In the present study, we performed a genome wide investigation of MYB10 in the diploid and octoploid Fragaria species. Further, we identified seven quantitative trait loci (QTLs) associated with fruit color in octoploid strawberry. In addition, we predicted 20 candidate genes primarily influencing the fruit color based on the QTL results and transcriptome analysis of fruit skin and flesh tissues of light pink, red, and dark red strawberries. Moreover, the computational and transcriptome analysis of MYB10 in octoploid strawberry suggests that the difference in fruit colors could be predominantly influenced by the expression of MYB10 from the F. iinumae subgenome. The outcomes of the present endeavor will provide a platform for the understanding and tailoring of anthocyanin pathway in strawberry for the production of fruits with aesthetic colors.