Polyploidy In Plants Research Articles

Occurrence and impact of polyploidy in dicotyledonous plants from Kinnaur, Himachal Pradesh (India)

Occurrence and impact of polyploidy in dicotyledonous plants from Kinnaur, Himachal Pradesh (India)

Higher order polyploids exhibit enhanced desiccation tolerance in the grass Microchloa caffra.

Desiccation tolerance evolved recurrently across diverse plant lineages to enable survival in water limited conditions. Many resurrection plants are polyploid and several groups have hypothesized that polyploidy contributed to the evolution of desiccation tolerance. However, due to the vast phylogenetic distance between resurrection plant lineages, the rarity of desiccation tolerance, and the prevalence of polyploidy in plants, this hypothesis has been difficult to test. Here, we surveyed natural variation in morphological, reproductive, and desiccation tolerance traits across several cytotypes of a single species to test for links between polyploidy and increased resilience. We sampled multiple natural populations of the resurrection grass Microchloa caffra across an environmental gradient ranging from mesic to xeric in South Africa. We describe two distinct ecotypes of M. caffra that occupy different extremes of the environmental gradient and exhibit consistent differences in ploidy, morphological, reproductive, and desiccation tolerance traits in both field and common growth conditions. Interestingly, plants with more polyploid genomes exhibited consistently higher recovery from desiccation, were less reproductive, and larger than plants with smaller genomes and lower ploidy. These data suggest that selective pressures in increasingly xeric sites may play a role in maintaining and increasing desiccation tolerance that are mediated by changes in ploidy.

Oryzalin delays germination and induces putative polyploidy plants in local North Sumatra garlic (Allium sativum L.)

Oryzalin is anti-mitotic herbicide. It has been used to induce polyploidy in several plants. The aim of this study was to determine the effectiveness of oryzalin in inducing polyploids and its physiological effects on North Sumatran local garlic (Allium sativum L.) germination. This study used a factorial completely randomized block design (CRBD). The first factor was oryzalin concentration with 5 treatment levels, namely R1 (0 µM), R2 (100 µM), R3(200 µM), R4 (300 µM) and R5 (400 µM). The second was soaking duration, consisting of H1 (24 hours) and H2 (48 hours). The parameters observed were percentage of germination and sprout morphology, observed at 1 and 3 weeks after treatment. The collected data were processed using ANOVA and if they were significantly different, it was continued with the DMRT test at a 5% significant level. The results showed that oryzalin suppressed garlic germination in the first week, but the effect disappeared and there was no significant difference in germination percentage at 3 weeks after soaking. Treatment with 200 µM for 48 hours and 400 µM oryzalin for 24 hours induced putative polyploidy garlic, the morphological shoot showed higher and thicker leaves than control.

Complex patterns of ploidy in a holocentric plant clade (Schoenus, Cyperaceae) in the Cape biodiversity hotspot.

It is unclear how widespread polyploidy is throughout the largest holocentric plant family - the Cyperaceae. Because of the prevalence of chromosomal fusions and fissions, which affect chromosome number but not genome size, it can be impossible to distinguish if individual plants are polyploids in holocentric lineages based on chromosome count data alone. Furthermore, it is unclear how differences in genome size and ploidy levels relate to environmental correlates within holocentric lineages, such as the Cyperaceae. We focus our analyses on tribe Schoeneae, and more specifically the southern African clade of Schoenus. We examine broad-scale patterns of genome size evolution in tribe Schoeneae and focus more intensely on determining the prevalence of polyploidy across the southern African Schoenus by inferring ploidy level with the program ChromEvol, as well as interpreting chromosome number and genome size data. We further investigate whether there are relationships between genome size/ploidy level and environmental variables across the nutrient-poor and summer-arid Cape biodiversity hotspot. Our results show a large increase in genome size, but not chromosome number, within Schoenus compared to other species in tribe Schoeneae. Across Schoenus, there is a positive relationship between chromosome number and genome size, and our results suggest that polyploidy is a relatively common process throughout the southern African Schoenus. At the regional scale of the Cape, we show that polyploids are more often associated with drier locations that have more variation in precipitation between dry and wet months, but these results are sensitive to the classification of ploidy level. Polyploidy is relatively common in the southern African Schoenus, where a positive relationship is observed between chromosome number and genome size. Thus, there may be a high incidence of polyploidy in holocentric plants, whose cell division properties differ from monocentrics.

Polyploidization in Orchids: From Cellular Changes to Breeding Applications.

Polyploidy occurs naturally in plants through cell division errors or can artificially be induced by antimitotic agents and has ecological effects on species adaptation, evolution, and development. In agriculture, polyploidy provides economically improved cultivars. Furthermore, the artificial induction of polyploids increases the frequency; thus, it accelerates obtaining polyploid plants used in breeding programs. This is the reason for its use in developing many crops of economic interest, as is the case of orchids in the flower market. Polyploidy in ornamental plants is mainly associated with flowers of larger size, fragrance, and more intense coloring when compared to naturally diploid plants. Currently, orchids represent the largest flower market worldwide; thus, breeding programs aim to obtain flowers with the larger size, durability, intense colors, and resistance to pathogens. Furthermore, orchid hybridization with polyploidy induction has been used to produce improved hybrid cultivars. Thus, the objective of this review was to compile information regarding the natural occurrence, importance, and methods of induction of polyploidy in orchids. The study also summarizes the significance of polyploids and techniques associated with artificially inducing polyploidy in different orchids of commercial relevance.

Induction of polyploidy through colchicine in cotton (Gossypium herbaceum) and its conformity by cytology and flow cytometry analyses

Cotton is one of the most important fibre crops in the world. An increase in ploidy level was observed in diploid cotton species namely Gossypium herbaceum in the experiment, through colchicine application. There were significant growth variations noticed during the induction of polyploidy in the cotton plants depending upon the concentration of colchicine, duration of the treatments and genotypes taken. An increase in the concentration of colchicine or the duration of the treatment had a retardation effect on seed viability in G. herbaceum. The hypocotyls of length between 4 and 8 mm were found to be most responsive to colchicine treatment. The root meristem of G. herbaceum, treated with 0.2 and 0.4% colchicine exhibited the most number of tetraploid cells during 16 h of treatment. The increase in the concentration of colchicine, along with an increase in duration of treatment led to the chromosomal abnormalities in the wild cotton species. Seed treatment for colchicine application, was the most efficient and reliable method when compared to Petri-plate application and cotton swabbing treatments for inducing polyploidy in diploid cotton.

Climate change, biosystematics and taxonomy

The history of biosystematics research and its impacts on climate goes before political ramifications. Climate change is altering the environments and likely to result in changes in the distribution of species, flowering times; migrate and adapt to the new environmental conditions; or extinction. Adaptive capacity is the ability of the plants to adapt to the impacts of climate change. Adaptation process is going in nature through phenotypic plasticity, natural selection or migration or polyploidization. The options are not mutually exclusive. Phenotypic plasticity may be the most efficient way of adaptation to a new environment. Polyploidization may increase tolerance to diverse ecological conditions and the high incidence of polyploidy in plants indicates its adaptive significance. Population having polyploid pillar complex is a good backup support towards microevolution and speciation, a mode of adaptation. The paper discusses about these biosystematics approaches towards adaptation to new environmental conditions resulting from climate change. It also discusses about the role of taxonomists under the changed circumstances. It is evident from the review that a set of biosystematics data along with other ecological and conservation information needs to be included in Flora and Monographs. It reveals that it was as far as worked out at the Paris Botanical Congress 1954 and put up by Stebbins in a series of proposals, termed as “Stebbins’ Ten Points” that needs further enrichment.
 Bangladesh J. Plant Taxon. 28(1): 277-287, 2021 (June)

Polyploidy induction by colchicine treatment in garlic (Allium sativum L.), and effects of polyploidy on some traits

The garlic plant (Allium sativum L) is a suitable indicator plant for the determination of potential genotoxic agents in the samples taken from the environment. Polyploidy has the utmost importance in horticulture for the development of new varieties with desirable morphological traits referring to plant size and vigor, leaf thickness, larger flowers with thicker petals, intense color of leaves and flowers, long lasting flowers, compactness, dwarfness and restored fertility. Polyploidy may occur naturally due to the formation of unreduced gametes or can be artificially induced by doubling the number of chromosomes in somatic cells. Usually, natural polyploid plants are unavailable, so polyploidy is induced synthetically with the help of mitotic inhibitors. Colchicine is a widely used mitotic inhibitor for the induction of polyploidy in plants during their cell division by inhibiting the chromosome segregation. The aim of this study was to determine the effect of various concentrations and duration of colchicine treatment on root length, number of roots and stomatal densities Allium sativum L.

The effect of Colchicine on Vicia faba and Chrysanthemum carinatum (L.) plants and their cytogenetical study

We have prepared various colchicine concentrations and applied them on seedling of Chrysanthemum carinatum (2n = 18) and seeds of Vicia faba (2n = 12). Colchicine-induced polyploidy was reported in Chrysanthemum carinatum (2n = 4x = 36) and Vicia faba (2n = 4x = 24) plants. This research explains the polyploidy in respective plants which successfully results in apparent morphological and cytological changes in polyploid plants compared to the control plants. Phenotypic characters exhibited that polyploid plants initially had slightly slower growth, stronger stems, thicker and larger leaves, larger flowers, and seeds and then increases abruptly. There was an increment in cytological characters such as cell size, chiasma frequency in polyploid plants as compared to the control plants. Growth patterns, morphology, pollen staining, and seed sets were recorded in this work. However, the main emphasis was laid on the behavior of chromosomes of isolated polyploids.

Polyploidy and its implications in plants breeding – A review

Polyploidy is a prominent force of shaping the evolution of in most of ferns and flowering plants. Polyploidy has tremendous contribution in plants improvement program. It is the polyploidy breeding through which new crops can be developed and interspecific genes can be transferred and also the origin of crops can be traced. It is now an interesting field of study to reveal the evolution of crop plants and utilizing their variability in the field of crop breeding. Polyploidy generally differ markedly from their progenitors in morphological, ecological, physiological and cytological characteristics that can contribute both to exploitation of a new niche and to reproductive isolation. As a result, polyploidy is a major mechanism of adaptation and speciation in plants. Another implication of polyploidy is development heterosis in plant breeding. Unlike diploids which may lose heterosis with each consecutive generation due to segregation, polyploidy imposes pairing of homologous chromosomes, thus preventing intergenomic recombination. In this way, heterozygosity is maintained throughout generations. One of the immediate and obvious consequences of polyploidy in plants is an increase in cell size which in turn leads to enlarged plant organs relative to diploids. It is also used in bridge crossing, development of seedless fruits like watermelon and production of apomictic crops.

The Technology Used for Synthetic Polyploid Production of Miscanthus as Cellulosic Biofuel Feedstock

Background: The contemporary bioethanol production technologies are based on the utilization of plant lignocellulosic biomass. These technologies require conducting regular search, breeding, and creation of new energy crops. In particular, significant attention is paid to plants of the genus Miscanthus - perennial grasses that have a great potential as renewable energy sources. The main advantages of representatives of this species are considered to be high biomass yield, cold tolerance, a low requirement to soil conditions, long-term use of plantation, etc. M. × giganteus is the most promising species of the genus. The last is a sterile allotriploid originated through the hybridization of M. sinensis and M. sacchariflorus. Due to the problem with sexual reproduction, there is a lack of genotypes necessary for plant breeding programs to improve this species. Thus, polyploidization is an indispensable approach for obtaining new genotypes of M. × giganteus. Objective: The aim of this work is to review the attempts and methodologies employed to induce polyploidy in plants belonging to the genus Miscanthus. Methods: For this purpose, the concentrations and duration of treatment with different antimitotic agents in species, within this genus, have been considered. Methods for ploidy level determination and evaluation of biological and biochemical traits in the resulting polyploids have also been reported. Results: The application of antimitotic agents in vitro is the most effective and commonly used method of polyploidization in Miscanthus. The most effective antimitotic compounds appeared to be the well-known dinitroanilines, such as oryzalin and trifluralin, as well as new dinitroanilines with significantly lower phytotoxicity level. Conclusion: Polyploidization in Miscanthus has been investigated by various research groups worldwide. Currently, polyploid forms of M. sinensis, M. sacchariflorus and M. × giganteus have been obtained. The biological and biochemical traits of the obtained polyploids differ significantly from their original forms. However, the challenge of fertility restoration of M. × giganteus has not been resolved yet.

A Collinearity-Incorporating Homology Inference Strategy for Connecting Emerging Assemblies in the Triticeae Tribe as a Pilot Practice in the Plant Pangenomic Era

Plant genome sequencing has dramatically increased, and some species even have multiple high-quality reference versions. Demands for clade-specific homology inference and analysis have increased in the pangenomic era. Here we present a novel method, GeneTribe (https://chenym1.github.io/genetribe/), for homology inference among genetically similar genomes that incorporates gene collinearity and shows better performance than traditional sequence-similarity-based methods in terms of accuracy and scalability. The Triticeae tribe is a typical allopolyploid-rich clade with complex species relationships that includes many important crops, such as wheat, barley, and rye. We built Triticeae-GeneTribe (http://wheat.cau.edu.cn/TGT/), a homology database, by integrating 12 Triticeae genomes and 3 outgroup model genomes and implemented versatile analysis and visualization functions. With macrocollinearity analysis, we were able to construct a refined model illustrating the structural rearrangements of the 4A-5A-7B chromosomes in wheat as two major translocation events. With collinearity analysis at both the macro- and microscale, we illustrated the complex evolutionary history of homologs of the wheat vernalization gene Vrn2, which evolved as a combined result of genome translocation, duplication, and polyploidization and gene loss events. Our work provides a useful practice for connecting emerging genome assemblies, with awareness of the extensive polyploidy in plants, and will help researchers efficiently exploit genome sequence resources.

Effect of Colchicine on In Vitro Growth and Ploidicity of Crown Vetiver Plant (Vetiveria zizanioides L. Nash)

The goal of this research was to evaluate the effect of colchicine on the formation and growth of shoot from explant crowns by in vitro, as well as to obtain polyploidy vetiver plant (Vetiveriazizanioides L. Nash). Induction of polyploidy vetiver plants carried out by culturing explant crowns on MS media supplemented by 2 mg.L-1 BAP and colchicine (0, 30, 60, 90, 120 mg.L-1) for three weeks. Explant and formed shoot regenerated on MS media containing 1 mg.L-1 NAA. The generated plantlets acclimatized on the growing media (cocopeat: husk charcoal: compost = 1: 1: 2). Plant ploidy level of the plants regenerated from treated explant estimated by chromosome counting in root tips. The effect of colchicine on media was able to induce polyploidy in vetiver plants. Five mixoploids were obtained from explant treated colchicine. The vetiver mixoploid plants obtained were 20% and 62.5% from colchicine 60 mg.L-1 and 90 mg.L-1, respectively. The vetiver mixoploid plants consist of diploid (2n=2x=20) and triploid cells (2n=3x=30) or diploid (2n=2x=20) and tetraploid (2n=4x=40). The addition of colchicine in concentrations above 30 mg.L-1 caused inhibition of shoot formation and growth, even a concentration of 120 mg.L-1 caused explant death. However, 30 mg.L-1 colchicine could increase the number of formed shoots, while only 60 mg.L-1 and 90 mg.L-1 could be induced the mixoploidy in the vetiver plant. The results showed that colchicine treatment could increase ploidicity in vetiver plants in vitro, but caused inhibition of shoot formation and growth.

Studies on Colchicine Induced Chromosome Doubling for Enhancement of Quality Traits in Ornamental Plants.

Polyploidy has the utmost importance in horticulture for the development of new ornamental varieties with desirable morphological traits referring to plant size and vigor, leaf thickness, larger flowers with thicker petals, intense color of leaves and flowers, long lasting flowers, compactness, dwarfness and restored fertility. Polyploidy may occur naturally due to the formation of unreduced gametes or can be artificially induced by doubling the number of chromosomes in somatic cells. Usually, natural polyploid plants are unavailable, so polyploidy is induced synthetically with the help of mitotic inhibitors. Colchicine is a widely used mitotic inhibitor for the induction of polyploidy in plants during their cell division by inhibiting the chromosome segregation. Different plant organs like seeds, apical meristems, flower buds, and roots can be used to induce polyploidy through many application methods such as dipping/soaking, dropping or cotton wool. Flow cytometry and chromosome counting, with an observation of morphological and physiological traits are routine procedures for the determination of ploidy level in plants.

Kinetochore protein depletion underlies cytokinesis failure and somatic polyploidization in the moss Physcomitrella patens.

Lagging chromosome is a hallmark of aneuploidy arising from errors in the kinetochore-spindle attachment in animal cells. However, kinetochore components and cellular phenotypes associated with kinetochore dysfunction are much less explored in plants. Here, we carried out a comprehensive characterization of conserved kinetochore components in the moss Physcomitrella patens and uncovered a distinct scenario in plant cells regarding both the localization and cellular impact of the kinetochore proteins. Most surprisingly, knock-down of several kinetochore proteins led to polyploidy, not aneuploidy, through cytokinesis failure in >90% of the cells that exhibited lagging chromosomes for several minutes or longer. The resultant cells, containing two or more nuclei, proceeded to the next cell cycle and eventually developed into polyploid plants. As lagging chromosomes have been observed in various plant species in the wild, our observation raised a possibility that they could be one of the natural pathways to polyploidy in plants.

Polyploidy in creosote bush (Larrea tridentata) shapes the biogeography of specialist herbivores

Whole-genome duplication (polyploidy) can influence the biogeography and ecology of plants that differ in ploidy level (cytotype). Here, we address how two consequences of plant polyploidy (parapatry of cytotypes and altered species interactions) shape the biogeography of herbivorous insects. Warm deserts of North America. Gall midges (Asphondylia auripila group, Diptera: Cecidomyiidae) that attack three parapatric cytotypes of creosote bush (Larrea tridentata, Zygophyllaceae). We surveyed Asphondylia species diversity at 177 sites across a 2300-km extent. After noting a correspondence between the distributions of eight Asphondylia species and L. tridentata cytotypes, we fine-mapped Asphondylia species range limits with transects spanning cytotype contact zones. We then tested whether plant-insect interactions and/or abiotic factors explain this coincidence by (1) comparing attack rates and gall midge communities on alternative cytotypes in a narrow zone of sympatry and (2) using species distribution models (SDMs) to determine if climatically suitable habitat for each midge species extended beyond cytotype contact zones. The range limits of 6/17 Asphondylia species (including two novel putative species confirmed with COI sequencing) perfectly coincided with the contact zone of diploid and tetraploid L. tridentata. One midge species was restricted to diploid host plants while five were restricted to tetraploid and hexaploid host plants. Where diploid and tetraploid L. tridentata are sympatric, cytotype-restricted midge species more frequently attacked their typical host and Asphondylia community structure differed markedly between cytotypes. SDMs predicted that distributions of cytotype-restricted midge species were not constrained by climatic conditions near cytotype contact zones. Contact zones between plant cytotypes are dispersal barriers for many Asphondylia species due to plant-insect interactions. The distribution of L. tridentata cytotypes therefore shapes herbivore species ranges and herbivore community structure across North American deserts. Our results demonstrate that polyploidy in plants can affect the biogeography of ecological communities.

EyeChrom and CCDBcurator: Visualizing chromosome count data from plants.

Premise of the StudyChromosome count data are available for hundreds of plant species and can be explored in text‐only format at the Chromosome Counts Database (http://ccdb.tau.ac.il). CCDBcurator and EyeChrom are an R package and a web application, respectively, that first curate and then visualize these data graphically, so that intra‐ and interspecific variation of chromosome numbers can be easily summarized and displayed for a given genus.Methods and ResultsWe developed R code to clean, summarize, and display in several formats the chromosome count data for a selected genus or set of species present in the Chromosome Counts Database. These data and figures can be exported for use in analyses, publications, or teaching.ConclusionsChromosome count data are critical for a number of evolutionary studies in plant biology, and their importance is underscored by the increasing appreciation of the prevalence of polyploidy in land plants. CCDBcurator and EyeChrom provide a fast, easy, and reproducible means of cleaning, curating, and then visualizing the chromosome count data currently available for plants.

ANALISIS FENOTIPE DAN PLOIDI TANAMAN MELON (Cucumis melo L.) HASIL PERLAKUAN EKSTRAK ETANOLIK DAUN TAPAK DARA (Catharanthus roseus [L] G. Don.)

Anti-mitotic agents such as colchicine have been used to induce polyploidy in various plants. On the other hand, vincristine and vinblastine are also antimitotic agent extracted from Periwincle (Catharanthus roseus [L] G. Don) were previously studied to produce autotetraploid on shallot tuber (Allium cepa L.). Therefore, in this study phenotype character and ploidy of muskmelon (Cucumis melo L.) produced by etanolic extract of periwikle leaves were determined. The effects of different concentration of etanolic extract of periwinkle leaves on polyploidy induction in muskmelon were examined. Melon seedling of two days old were immersed in 0.5%, 0.1%, and 0.05% for 8 hours. Then seedling was grown on the polybag and a drop of each concentration of periwinkle leaves’s etanolic extract was added into apical shoot. Melon seedling of ten days old were moved and cultivated and harvested on 60 days after cultivation. Phenotypic character such as: plant high, stem diameter, leaf area, fruit weight, fruit area around, flesh fruit thickness, skin fruit thickness, fruit horizontal diameter, fruit, vertical diameter, number of seeds, weight of 100 gram of seed, seed leght, seed width, and seed thickness were examined. The ploidy degree was determined by count of chromosome number root tips of second generation muskmelon sprout. Result of this study revealed that 0.05% etanolic extract of periwinkle leaves for 8 hours immersed is optimum concentration to induce autotetraploid muskmelon (4n=48). Autotetraploid phenotypic character of muskmelon produced by 0.05% etanolic extract of periwinkle leaves were generally bigger than control plants statistically significant in stem diameter, leaf area, and fruit horizontal diameter. The result also showed that the chromosome number of second generation autotetraploid muskmelon sprout was tetraploid (4n=48).

Widespread generalist clones are associated with range and niche expansion in allopolyploids of Pacific Northwest Hawthorns (Crataegus L.).

Range and niche expansion are commonly associated with transitions to asexuality, polyploidy and hybridity (allopolyploidy) in plants. The ability of asexual polyploids to colonize novel habitats may be due to widespread generalist clones, multiple ecologically specialized clones, or may be a neutral by-product of multiple, independent origins of asexual polyploids throughout the range. We have quantified niche size and divergence for hawthorns of the Pacific Northwest using data from herbarium vouchers with known cytotypes. We find that all polyploid niches diverge from that of the diploid range, and allopolyploids have the broadest niches. Allotetraploids have the largest niche and the widest geographic distribution. We then assessed the genetic mechanism of range expansion by surveying the ecological and geographic distribution of genotypes within each cytotype from sites in which fine-scale habitat assessments were completed. We find no isolation by either geographic or ecological distance in allopolyploids, suggesting high dispersal and colonization ability. In contrast, autotriploids and diploids show patterns of isolation by geographic distance. We also compared the geographic and ecological distributions of clonal genotypes with those of randomly drawn sites of the most widespread cytotype. We found that most clones are geographically widespread and occur in a variety of habitats. We interpret these findings to suggest that patterns of range and niche expansion in Pacific Northwest Hawthorns may stem from these widespread, ecologically generalist clones of hybrid origin.

Karyotypes of nineteen species of Asteraceae in the Hengduan Mountains and adjacent regions

The Hengduan Mountains region is a biodiversity hotspot. In this study, we report the karyotypes of 19 species (21 populations) of Asteraceae from this region, 14 of which are reported for the first time. We also examined polyploidy in Asteraceae plants and summarized karyotype data in the literature for 69 congeneric taxa. In these genera, there were five different ploidy levels in the region, though the most dominant was diploid (73.08%). There is no direct evidence that ploidy level and karyotype asymmetry are associated with the distribution of recorded Asteraceae species from the Hengduan Mountains. This suggests that polyploidy (26.92%) may not play an important role in the evolutionary history of these plants, even though, among these genera, the ratio of paleopolyploidy was high (46.15%).