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Tetraploid oysters are valuable germplasm resources for the production of triploid oysters. However, the broodstock condition and gonadal development of tetraploid oysters are poorly understood. To assess the effects of temperature on gamete quantity and quality, tetraploid and diploid oysters were held at controlled temperatures of 18, 20 and 22 °C for 120 days. The gametogenesis process in tetraploid and diploid oysters showed an accelerated trend in response to increased conditioning temperatures. Nonetheless, the gonadal development of tetraploid oysters was slower than that of diploid oysters. Histomorphometric analysis of gonadal tissues showed variations in observed sex ratio under different conditioning temperatures. The proportions of tetraploid and diploid males increased with elevated temperature. However, survival rates of tetraploid and diploid oysters at 22 °C were significantly lower than those at 18 and 20 °C (P < 0.05). In terms of the number of oocytes and spermatozoa, tetraploid oysters were fewer than diploid oysters. Overall, these results demonstrated the differences in broodstock conditioning and gonadal development between tetraploid and diploid oysters, suggesting the need for specialized broodstock cultivation strategies for tetraploid oysters. [ABSTRACT FROM AUTHOR]

Passiflora edulis Sims (2n = 18) is a perennial plant with high utilization values, but its spontaneous polyploidy in nature has yet to be seen. Thus, this study aims to enhance our understanding of polyploidy P. edulis and provide rudimentary knowledge for breeding new cultivars. In this study, colchicine-induced tetraploid P. edulis (2n = 36) was used as experimental material (T1, T2, and T3) to explore the variances between it and its diploid counterpart in morphology, physiology, and biochemical characteristics, and a comparison of their performance under cold stress was conducted. We measured and collected data on phenotype parameters, chlorophyll contents, chlorophyll fluorescence, photosynthesis, osmotic substances, and antioxidant enzymes. The results showed that tetraploid P. edulis exhibited a shorter phenotype, more giant leaves, darker leaf color, and longer and fewer roots. Moreover, the physiological and biochemical analysis indicated that the tetraploid P. edulis had better photosynthesis systems and higher chlorophyll fluorescence parameters than the diploid P. edulis. Additionally, the tetraploid P. edulis had higher activity of antioxidant enzymes (SOD, POD, CAT) and lower MDA content to maintain better resistance in low temperatures. Overall, we conclude that there were apparent differences in the morphological, physiological, and biochemical traits of the tetraploid and diploid P. edulis. The tetraploid plants showed better photosynthesis systems, higher osmotic substance content, and antioxidant enzyme activity than the diploid, even under cold stress. Our results suggest that tetraploids with more abundant phenotype variation and better physiological and biochemical traits may be used as a new genetic germplasm resource for producing new P. edulis cultivars. [ABSTRACT FROM AUTHOR]

Phellodendron amurense Rupr. is a precious medicinal tree species in northeast China. However, P. amurense resources have been severely destroyed due to uncontrolled overharvest and the limited innovation of new germplasms by traditional cross-breeding. In this study, polyploid breeding was introduced to the improvement program of P. amurense. Fifty-four tetraploid plants of P. amurense were first produced by colchicine-induced adventitious bud chromosome doubling in stem segment explants. The induction frequency reached 36.16% (1.0 g L−1 colchicine solution for 48 h treatment) and 50.00% (2.0 g L−1 colchicine solution for 24 h treatment), respectively, showing the high efficiency of the somatic chromosome doubling based on the organogenesis system. Tetraploidization resulted in significant phenotypic variation, such as larger and thicker leaves, thicker stems, and bigger stomata. Ultra-performance liquid chromatography–mass spectrometry (UPLC–MS/MS) analysis identified 59 differentially accumulated alkaloids (DAAs) between the leaf and stem samples of tetraploids, including 32 upregulated and 27 downregulated in stems. For both leaf and stem samples, 18 DAAs were identified between diploids and tetraploids, with 16 DAAs upregulated in tetraploid leaves and 8 upregulated in tetraploid stems, suggesting that polyploidization caused significant alterations in alkaloid contents in leaves and stems of P. amurense. The contents of the main medicinal compounds, such as berberine, jatrorrhizine, phellodendrine, and palmatine, increased significantly in the leaf and/or stem samples after polyploidization. This finding implied that polyploid breeding might be an effective approach for improving P. amurense, beneficial to preserving and exploiting natural resources. [ABSTRACT FROM AUTHOR]

Interspecific F1 hybrids between Asian (Oryza sativa) and African rice (Oryza glaberrima) exhibit severe sterility caused by the accumulation of hybrid sterility genes/loci at 15 or more loci. The mechanisms underlying the hybrid sterility genes are largely unknown; however, a few genes associated with the killer–protector system, which is the system most frequently associated with hybrid sterility genes, have been identified. We previously produced fertile plants as tetraploids derived from diploid interspecific F1 hybrids through anther culture; therefore, it was suggested that hybrid sterility could be overcome following tetraploidization. We investigated whether tetraploid interspecific plants produced by crossing are fertile and tested the involvement of hybrid sterility genes in the process. Fertile tetraploid interspecific F1 hybrid plants were obtained by crossing 2 tetraploids of O. sativa and O. glaberrima. To elucidate the relationships between pollen fertility and the hybrid sterility loci in the tetraploid F1 microspores, we performed genetic analyses of the tetraploid F2 hybrids and diploid plants obtained from the microspores of tetraploid interspecific hybrids by anther culture. The result suggested that the tetraploid interspecific hybrids overcame pollen and seed infertility based on the proportion of loci with the killer–protector system present in the tetraploids. The heterozygous hybrid sterility loci with the killer–protector system in the tetraploid segregate the homozygous killed allele (16.7–21.4%), with more than three-quarters of the gametes surviving. We theoretically and experimentally demonstrated that fertile rice progenies can be grown from tetraploid interspecific hybrids. [ABSTRACT FROM AUTHOR]

Polyploid rice and its reverted diploid show rich phenotypic variation and strong heterosis, showing great breeding value. However, the genomic differences among tetraploids, counterpart common diploids, tetraploid-revertant diploids, and hybrid descendants are unclear. In this work, we bred a new excellent two-line hybrid rice variety, Y Liang You Duo Hui 14 (HTRM12), using Haitian tetraploid self-reverted diploid (HTRM2). Furthermore, we comparatively analyzed the important agronomic traits and genome-wide variations of those closest relatives, Haitian diploid (HT2), Haitian tetraploid (HT4), HTRM2, and HTRM12 in detail, based on multiple phenotypic investigations, genome resequencing, and bioinformatics analysis. The results of agronomic traits analysis and genome-wide variation analysis of single nucleotide polymorphism (SNP), insertion–deletion (InDel), and copy number variation (CNV) show that HT4 and HTRM2 had abundant phenotypic and genomic variations compared to HT2. HTRM2 can inherit important traits and variations from HT4. This implies that tetraploid self-reverted diploid has high potential in creating excellent breeding materials and in breeding breakthrough hybrid rice varieties. Our study verifies the feasibility that polyploid rice could be used as a mutation carrier for creating variations and provides genomic information, new breeding materials, and a new way of application for tetraploid rice breeding. [ABSTRACT FROM AUTHOR]

Cultivated potato, Solanum tuberosum L., is considered an autotetraploid with 12 chromosomes with four homologous phases. However, recent evidence found that, due to frequent large phase deletions in the genome, gene ploidy is not constant across the genome. The elite cultivar "Otava" was found to have an average gene copy number of 3.2 across all loci. Breeding programs for elite potato cultivars rely increasingly on genomic prediction tools for selection breeding and elucidation of quantitative trait loci underpinning trait genetic variance. These are typically based on anonymous single nucleotide polymorphism (SNP) markers, which are usually called from, for example, SNP array or sequencing data using a tetraploid model. In this study, we analyzed the impact of using whole genome markers genotyped as either tetraploid or observed allele frequencies from genotype-by-sequencing data on single-trait additive genomic best linear unbiased prediction (GBLUP) genomic prediction (GP) models and single-marker regression genome-wide association studies of potato to evaluate the implications of capturing varying ploidy on the statistical models employed in genomic breeding. A panel of 762 offspring of a diallel cross of 18 parents of elite breeding material was used for modeling. These were genotyped by sequencing and phenotyped for five key performance traits: chipping quality, length/width ratio, senescence, dry matter content, and yield. We also estimated the read coverage required to confidently discriminate between a heterozygous triploid and tetraploid state from simulated data. It was found that using a tetraploid model neither impaired nor improved genomic predictions compared to using the observed allele frequencies that account for true marker ploidy. In genome-wide associations studies (GWAS), very minor variations of both signal amplitude and number of SNPs supporting both minor and major quantitative trait loci (QTLs) were observed between the two data sets. However, all major QTLs were reproducible using both data sets. [ABSTRACT FROM AUTHOR]

This research is conducted to study the induction of polyploidization in Katokkon chili using colchicine to study the effect of chromosome doubling or polyploid on certain superior characters during the seedling phase. Some morphological alterations were determined and proven to persist during the seedling phase. The study was conducted in the laboratory and screen house of the Department of Agronomy, Faculty of Agriculture, Universitas Hasanuddin. The polyploidy of the Katokkon chili is induced by soaking the germinated seeds in 0%, 0.05%, 0.1%, and 0.2% colchicine solutions for 6, 12, 24, and 48 hours each. Ploidy levels are analyzed using flow cytometry (Partec®Cy-Flow Space TM). Results show significant differences in colchicine treatment affecting all parameters observed: hypocotyl base of sprouts, plant height, stomata size, and the number of lateral shoots. Flow cytometry analysis histogram confirmed that administration of 0.1% colchicine concentration with 48 hours soaking time and 0.2% colchicine concentration with 24- or 48-hour soaking time can induce tetraploid plants (4n=48) with different coefficients of variance (CV-x%), 5.36%, 4.65%, 6.08%, respectively. Vigorous growth phenotype in leaf size and plant height was more clearly seen in the one-month-old tetraploid Katokkon chili seedlings induced by 0.10% with a soaking time of 48 hours.

Abstract Background Glehnia littoralis is a medicinal and edible plant species having commercial value and has several hundred years of cultivation history. Polyploid breeding is one of the most important and fastest ways to generate novel varieties. To obtain tetraploids of G. littoralis in vitro, colchicine treatment was given to the seeds and then were screened based on morphology, flow cytometry, and root tip pressing assays. Furthermore, transcriptome analysis was performed to identity the differentially expressed genes associated with phenotypic changes in tetraploid G. littoralis. Results The results showed that 0.05% (w/v) colchicine treatment for 48 h was effective in inducing tetraploids in G. littoralis. The tetraploid G. littoralis (2n = 4x = 44) was superior in leaf area, leaf thickness, petiole diameter, SPAD value (Chl SPAD), stomatal size, epidermal tissues thickness, palisade tissues thickness, and spongy tissues thickness to the diploid ones, while the stomatal density of tetraploids was significantly lower. Transcriptome sequencing revealed, a total of 1336 differentially expressed genes (DEGs) between tetraploids and diploids. Chromosome doubling may lead to DNA content change and gene dosage effect, which directly affects changes in quantitative traits, with changes such as increased chlorophyll content, larger stomata and thicker tissue of leaves. Several up-regulated DEGs were found related to growth and development in tetraploid G. littoralis such as CKI, PPDK, hisD and MDP1. KEGG pathway enrichment analyses showed that most of DEGs were enriched in metabolic pathways. Conclusions This is the first report of the successful induction of tetraploids in G. littoralis. The information presented in this study facilitate breeding programs and molecular breeding of G. littoralis varieties.

Near-infrared spectroscopy (NIR) has become an essential tool for non-destructive analysis in various fields, including aquaculture. This study presents a pioneering application of portable NIR spectrometers to analyze glycogen content in the gonadal tissues of the Pacific oyster (Crassostrea gigas), marking the first instance of developing quantitative models for glycogen in tetraploid C. gigas. The research also provides a comparative analysis with models for diploid and triploid oysters, underscoring the innovative use of portable NIR technology in aquaculture. Two portable NIR spectrometers were employed: the Micro NIR 1700 (908–1676 nm) and the Micro PHAZIR RX (1624–2460 nm). Near-infrared spectra were acquired from the gonadal tissues of diploid, triploid, and tetraploid C. gigas. Quantitative models for glycogen content were developed and validated using cross-validation methods. Additionally, qualitative models for different ploidies and genders were established. For the Micro NIR 1700, the cross-validation correlation coefficients (Rcv) and cross-validation relative predictive errors (RPDcv) for glycogen were 0.949 and 3.191 for diploids, 0.915 and 2.498 for triploids, and 0.902 and 2.310 for tetraploids. The Micro PHAZIR RX achieved Rcv and RPDcv values of 0.781 and 2.240 for diploids, 0.839 and 2.504 for triploids, and 0.717 and 1.851 for tetraploids. The Micro NIR 1700 demonstrated superior quantitative performance, with RPD values exceeding 2, indicating its effectiveness in predicting glycogen content across different ploidy levels. Qualitative models showed a performance index of 91.6 for diploid and 95 for tetraploid genders using the Micro NIR 1700, while the Micro PHAZIR RX achieved correct identification rates of 99.79% and 100% for diploid and tetraploid genders, respectively. However, differentiation of ploidies was less successful with both instruments. This study's originality lies in establishing the first quantitative models for glycogen content in tetraploid C. gigas using portable NIR spectrometers, highlighting the significant advancements in non-destructive glycogen analysis. The applicability of these findings is substantial for oyster breeding programs focused on enhancing meat quality traits. These models provide a valuable phenotyping tool for selecting oysters with optimal glycogen content, demonstrating the practical utility of portable NIR technology in aquaculture. [ABSTRACT FROM AUTHOR]

Polyploidization produces abundant phenotypic variation. Little is currently known about adventitious root (AR) development variation due to polyploidization. In this study, we analyzed the morphological, cytological, and physiological variations in AR development between tetraploid and diploid Populus plants during in vitro rooting culture. Compared to the diploids, the AR formation times and rooting rates of the tetraploids' stem explants had non-significant changes. However, the tetraploid ARs exhibited significantly slower elongation growth than the diploid ARs. Cytological observation showed that the tetraploid ARs were characterized by shorter root meristems and reduced meristem cell numbers, suggesting the reasons for the slow AR elongation. Analysis of hormones and related metabolites during AR development demonstrated that the total auxin, cytokinin, and jasmonic acid contents were significantly lower in the tetraploid ARs than in those of the diploids, and that the ratio of total auxins to total CKs at 0 h of AR development was also lower in the tetraploids than in the diploids, whereas the total salicylic acid content of the tetraploids was consistently higher than that of the diploids. qPCR analysis showed that the expression levels of several hormone signaling and cell division-related genes in the tetraploid ARs significantly differed from those in the diploids. In conclusion, the slow elongation of the tetraploid ARs may be caused by the endogenous hormone-mediated meristem shortening. Our findings enhance the understanding of polyploidization-induced variation in AR development of forest trees. [ABSTRACT FROM AUTHOR]

Perennial ryegrass is the most widely grown temperate grass species globally as a source of forage (grazing, hay, silage) or for amenity use. It is a part of landscape, protects soil from water and wind erosion, enriches it with organic substances and improves its fertility. During the period 2015-2020 in the Institute of Forage crops (IFC) - Pleven a collection nursery was studied in field non-irrigated conditions on leached black soil, in block duplicate method, in 2 replications with a total of 19 accessions of perennial ryegrass, with 50 individual plants each (25 plants for forage and 25 plants - for seeds), including 14 varieties and 5 ecotypes, 10 tetraploid and 9 diploid, from Bulgaria (BG), Belgium (BE), and Romania (RO). The aim is to determine the vitality per year and longevity (after many years, more than 3-4) of perennial ryegrass collection accessions and to make a selection of the most vital and long - lasting genotypes. Scale of survival according to the International Classifier for the family Poaceae (Bukhteeva et al., 1985) was used - limiting factors of the environment are cold - winter, drought and high temperatures - summer. An autumn inventory of the individual plants no./% was carried out annually, as 25 plants per sample = 100%., and vitality classification as follows: Very Low - less than 1 to 20% of plants are left alive; Low - more than 21 to 50%; Medium - more than 51% to 70%; High - more than 71 to 90%; Very High - more than 90% of the plants are still alive. Computer statistical processing of the data (via Excel, at P = 0.05) included variance analyses. Data on vitality and longevity are characterized by: marginal values (min and max), arithmetic mean (x), standard deviation (SD) and coefficient of variation (CV,%). Variation was considered weak, moderate, or strong at CV values, respectively: up to 10%; > 10-20%, and > 20% (Dimova and Marinkov, 1999). When grown for fodder, the local ecotypes Sokolare, Topolovgrad and Bekovi skali are the most viable by years and the longest surviving up to 5 years, with the percentage of plants alive in the fifth year being the highest for the Sokolare ecotype. Ecotype Sokolare is strongly influenced by the method of use, which is the longest-lasting and most viable when grown for fodder - 5 years and the shortest - when grown for seeds - 3 years. All diploid varieties live up to 4 years, and only the Harmoniya variety up to 5 years, with the Bulgarian varieties Harmoniya and Strandzha being the most viable and long-lasting when grown for fodder. Harvesting once a year for seeds extends the life cycle of diploid varieties up to 5 years and for the Harmoniya variety - up to 6. The Bulgarian tetraploid varieties Tetrany, Tetramis and the Belgian varieties Floris, Melpetra and Melverde are the most durable and long-lasting. One-time harvesting per year for seeds extends the life cycle of the tetraploid varieties up to 5 years, and for the Bulgarian varieties Tetrany, Tetramis and the Belgian varieties Floris, Melpetra and Melverde - up to 6. [ABSTRACT FROM AUTHOR]

Teak, known for its high-quality timber and economic value, holds significant potential as the major component of an agroforestry system to combat climate change and support sustainable development goals. The challenge of slow teak growth can be addressed by introducing fast-growing teak varieties amenable to vegetative propagation. Furthermore, the improvement of teak through somatic cell genetics, such as inducing polyploidy, can result in more vigorous, faster-growing, and drought-tolerant trees. While a report exists on a tetraploid teak accession with enhanced less water tolerance, information on the induction and characterization of tetraploid teak is lacking. In this study, we report the induction of polyploid teak by immersing 1 – 1.5 cm nodal stem segments and shoot tips obtained from teak shoot cultures in a modified MS liquid medium containing 5 − 30 µM oryzalin for one week, followed by subculture for 6 passages. The resulting shoots were acclimatized and grown in the nursery for 10 months. Based on flow cytometry for ploidy analysis of pre-selected plants having morphologies typical of polyploid followed by chromosome counting, we identified two tetraploid plants from one accession and 18 mixoploid teak plants from four accessions. Chromosome counting analysis confirmed that a diploid plant had a chromosome number of 2n = 2x = 36, tetraploid plant had a chromosome number of 2n = 4x = 72, and mixoploid plant exhibited both chromosome number of 2n = 2x = 36 and 2n = 4x = 72 in root tip cells. Morphological characterization revealed that tetraploid and mixoploid teak plants displayed typical polyploid characteristics, such as larger, thicker, and greener leaves, increased root diameter, increased cell size in root tip region, and larger stomata size but with reduced density. The development of tetraploid teak holds the potential to provide faster-growing and more drought-tolerant varieties, facilitating breeding efforts, including the development of triploid varieties.

Under salt stress, recretohalophyte Plumbago auriculata tetraploids enhance salt tolerance by increasing selective secretion of Na+ compared with that in diploids, although the mechanism is unclear. Using non-invasive micro-test technology, the effect of salt gland Ca2+ content on Na+ and K+ secretion were investigated in diploid and tetraploid P. auriculata under salt stress. Salt gland Ca2+ content and secretion rates of Na+ and K+ were higher in tetraploids than in diploids under salt stress. Addition of exogenous Ca2+ increased the Ca2+ content of the salt gland in diploids and is accompanied by an increase in the rate of Na+ and K+ secretion. With addition of a Ca2+ channel inhibitor, diploid salt glands retained large amounts of Ca2+, leading to higher Ca2+ content and Na+ secretion rate than those of tetraploids. Inhibiting H2O2 generation and H+-ATPase activity altered Na+ and K+ secretion rates in diploids and tetraploids under salt stress, indicating involvement in regulating Na+ and K+ secretion. Our results indicate that the increased Na+ secretion rate of salt gland in tetraploids under salt stress was associated with elevated Ca2+ content in salt gland. [ABSTRACT FROM AUTHOR]

Cross-incompatibility is the major challenge in inter-sectional distant hybridization between tree peonies (Paeonia sect. Moutan) and herbaceous peonies (Paeonia sect. Paeonia). Most of the intersectional cross combinations rarely produce hybrid progenies or even seeds. However, a combination with Paeonia × lemoinei Rehd. (P. delavayi × P. suffruticosa, tree type) as the pollen parent and P. lactiflora (herbaceous) as the seed parent resulted in many progenies. This research focuses on cytogenetics of two highly compatible intersectional combinations, P. lactiflora ‘Martha W.’ × P. × lemoinei ‘Golden Era’ (‘MW’ × ‘GE’) and P. lactiflora ‘Fen Yun Fei He’ × P. × lemoinei ‘L’Esperance’ (‘FYFH’ × ‘LE’). Karyotype analysis combined with genomic in situ hybridization (GISH) showed that the seed parents, ‘MW’ and ‘FYFH’, are both diploids (2n = 2x = 10, CC), while the pollen parents, ‘GE’ and ‘LE’, are tetraploid (2n = 4x = 20, AABB) and diploid (2n = 2x = 10, AB) respectively. Four progenies from ‘MW’ × ‘GE’, and another four progenies from ‘FYFH’ × ‘LE’, are all triploids (2n = 3x = 15, ABC). P. × lemoinei contributes two sets of chromosomes (AB) showing distinct signals in all tested triploids. The essential of a successful intersectional hybridization is to obtain 2x gametes from tree peony. P. × lemoinei has better compatibility in intersectional hybridization than other tree peony species, probably because of its higher frequency of 2x gamete (unreduced in diploid, or reduced in tetraploid) generation. Tetraploid tree peonies, such as ‘GE’, might produce abundant 2x gametes through normal meiosis, which is the possible reason for their better fertility and superior intersectional compatibility than diploid tree peonies. The mechanism of compatibility in intersectional hybridization is supposed to be a rebalance between the distant divergent parents, tree peonies and herbaceous peonies, triggered by ploidy increase of gametes from tree peonies. The discovery of tetraploid tree peony also provides valuable materials to study the mechanism of polyploidization in sect. Moutan, and to promote the distant hybridization breeding in Paeonia. [ABSTRACT FROM AUTHOR]

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One of the important functions of regulated cell death is to prevent cells from inappropriately acquiring extra copies of their genome, a state known as polyploidy. Apoptosis is the primary cell death mechanism that prevents polyploidy, and defects in this apoptotic response can result in polyploid cells whose subsequent error-prone chromosome segregation are a major contributor to genome instability and cancer progression. Conversely, some cells actively repress apoptosis to become polyploid as part of normal development or regeneration. Thus, although apoptosis prevents polyploidy, the polyploid state can actively repress apoptosis. In this review, we discuss progress in understanding the antagonistic relationship between apoptosis and polyploidy in development and cancer. Despite recent advances, a key conclusion is that much remains unknown about the mechanisms that link apoptosis to polyploid cell cycles. We suggest that drawing parallels between the regulation of apoptosis in development and cancer could help to fill this knowledge gap and lead to more effective therapies. [ABSTRACT FROM AUTHOR]

Seedlessness is the most important characteristic of citrus and one of its breeding purposes. Triploids are the most reliable way to secure seedlessness and can be developed through crosses between tetraploids and diploids or between diploids and diploids. We evaluated the characteristics of seed formation and recovery frequency of triploids in interploid crosses in this study. Normal seed formation was the highest (85.0%) in crosses of 2x × 2x, followed by crosses 4x × 2x and 2x × 4x. Partially developed seeds were obtained at the highest rate (35.3%) from crosses of 4x × 2x with 0.7 seeds per fruit, followed by 2x × 2x and 2x × 4x with 0.2 and 0.1 seeds per fruit, respectively. The number of undeveloped seeds per fruit was 1.1, 1.0, and 0.3 from the 4x × 2x, 2x × 4x, and 2x × 2x crosses, respectively, and the lowest frequency was recorded in the 2x × 2x cross. Diploid plants were mostly obtained in the 2x × 2x cross (98.8%), while 73.0% triploids and 27.0% tetraploids were obtained with 4x × 2x, and 14.3% diploids, 57.1% triploids, and 28.6% tetraploids were achieved with the 2x × 4x cross. Diploid plants were mostly obtained from normal seeds, while ad triploid and tetraploid plants were mostly obtained from partially developed and undeveloped seeds. The results indicated that crosses of 4x × 2x were the most efficient and that in vitro culture should be applied to rescue plants from partially developed and undeveloped seeds in triploid breeding programs. [ABSTRACT FROM AUTHOR]

Nonapomictic citrus tetraploids are desirable in citrus breeding for the production of triploid, seedless varieties, and polyploid rootstocks. However, only a few lines have been reported, and they were all generated using chemical methods. A 2x + 4 × cytochimera of the nonapomictic citrus variety 'Orah' mandarin, which developed from a bud mutant, was found due to its morphology differing from that of diploid plants and characterised via ploidy analysis combining flow cytometry and chromosome observation. The chimaera was stable, and there were 1.86–1.90 times as tetraploid cells as diploid cells. Anatomical structure observation revealed that the 'Orah' chimaera may be a periclinal chimaera with diploid cells in the L1 layer and tetraploid cells in the L2 and L3 layers. The chimaera showed some typical traits of polyploid plants, including thicker shoots, wider and thicker leaves, larger flowers and fruits, and fewer but larger seeds in fruits than in diploid plants. Almost all the seeds of the chimaera were monoembryonic. Most of the self-pollinated progenies of the chimaera were identified as tetraploids, and some triploid, pentaploid, and hexaploid plants were found. As a female, the chimaera produced allotriploids when crossed with Australian finger lime. In addition, 6 plants developed from polyembryonic seeds of the chimaera were identified as sexual tetraploid progenies with low-level recombinant genomes. Therefore, the 'Orah' 2x + 4 × chimaera can be used as a female parent to produce hybrid triploid and tetraploid citrus plants with high efficiency. Identification of the chimaera demonstrated that tetraploid citrus plants, especially nonapomictic varieties, can be generated from shoot bud mutants. [ABSTRACT FROM AUTHOR]

The sterility advantages of triploids make them paramount for oyster aquaculture. Tetraploids are always used as male parents for triploid industrial breeding in current hatcheries, thus they are the core asset for triploid oyster culture. The oyster Crassostrea angulata is the most productive oyster species in China. However, the optimal conditions for tetraploid induction have never been examined. In this study, we investigated the effectiveness of three induction methods (Method I, 2n ♀ × 2n ♂ + inducer abbreviated as DD + ind; Method II, 3n ♀ × 2n ♂ + inducer abbreviated as TrD + ind; Method III, 2n ♀ × 4n ♂ + inducer abbreviated as DT + ind) and three inducers (salinity; cytochalasin B, CB; and 6-dimethylaminopurine, 6-DMAP) for tetraploid induction in C. angulata. The optimal induction conditions for the three induction methods were a CB concentration of 0.5 mg/L treated for 20 min, 0.75 mg/L CB for a constant induction treatment of 20 min and 6-DMAP at a concentration of 100 mg/L for 20 min, respectively. When the optimal induction conditions were applied to a single pair of oysters, the D-larval tetraploid rate for the three methods were 18.93 ± 1.46%, 58.32 ± 1.03% and 51.61 ± 1.37%, respectively. After 30 days, the survival rates of the experimental groups were only 10.36 ± 2.51%, 28.07 ± 2.03% and 21.99 ± 1.27%, respectively, at day 30. The tetraploid rates in DD + ind and DT + ind were both decreased significantly over time, but they still reached 11.81% and 21.99% at 30 days, and 8% and 16% at day 180, respectively. Tetraploid rates in TrD + ind were 58.32 − 71.28% at the larval stage and 80% at day 180. In summary, despite very different induction rates, surviving tetraploids of C. angulata could be obtained in all three methods. Method II (TrD + inducer) was regarded as the optimal method to induce C. angulata tetraploids, and the optimal induction condition was a CB concentration of 0.75 mg/L and treated for 20 min under this method. [ABSTRACT FROM AUTHOR]

Lycium chinense, a type of medicinal and edible plant, is rich in bioactive compounds beneficial to human health. In order to meet the market requirements for the yield and quality of L. chinense, polyploid induction is usually an effective way to increase plant biomass and improve the content of bioactive components. This study established the most effective tetraploid induction protocol by assessing various preculture durations, colchicine concentrations, and exposure times. The peak tetraploid induction efficacy, 18.2%, was achieved with a 12-day preculture and 24-h exposure to 50 mg L–1 colchicine. Compared to diploids, tetraploids exhibited potentially advantageous characteristics such as larger leaves, more robust stems, and faster growth rates. Physiologically, tetraploids demonstrated increased stomatal size and chloroplast count in stomata but reduced stomatal density. Nutrient analysis revealed a substantial increase in polysaccharides, calcium, iron, and zinc in tetraploid leaves. In addition, seventeen carotenoids were identified in the leaves of L. chinense. Compared to the diploid, lutein, β-carotene, neoxanthin, violaxanthin, and (E/Z)-phytoene exhibited higher levels in tetraploid strains T39 and T1, with T39 demonstrating a greater accumulation than T1. The findings suggest that the generated tetraploids harbor potential for further exploitation and lay the foundation for the selection and breeding of novel genetic resources of Lycium. [ABSTRACT FROM AUTHOR]

Cultivated potato, Solanum tuberosum L., is considered an autotetraploid with 12 chromosomes with four homologous phases. However, recent evidence found that, due to frequent large phase deletions in the genome, gene ploidy is not constant across the genome. The elite cultivar “Otava” was found to have an average gene copy number of 3.2 across all loci. Breeding programs for elite potato cultivars rely increasingly on genomic prediction tools for selection breeding and elucidation of quantitative trait loci underpinning trait genetic variance. These are typically based on anonymous single nucleotide polymorphism (SNP) markers, which are usually called from, for example, SNP array or sequencing data using a tetraploid model. In this study, we analyzed the impact of using whole genome markers genotyped as either tetraploid or observed allele frequencies from genotype-by-sequencing data on single-trait additive genomic best linear unbiased prediction (GBLUP) genomic prediction (GP) models and single-marker regression genome-wide association studies of potato to evaluate the implications of capturing varying ploidy on the statistical models employed in genomic breeding. A panel of 762 offspring of a diallel cross of 18 parents of elite breeding material was used for modeling. These were genotyped by sequencing and phenotyped for five key performance traits: chipping quality, length/width ratio, senescence, dry matter content, and yield. We also estimated the read coverage required to confidently discriminate between a heterozygous triploid and tetraploid state from simulated data. It was found that using a tetraploid model neither impaired nor improved genomic predictions compared to using the observed allele frequencies that account for true marker ploidy. In genome-wide associations studies (GWAS), very minor variations of both signal amplitude and number of SNPs supporting both minor and major quantitative trait loci (QTLs) were observed between the two data sets. However, all major QTLs were reproducible using both data sets.

Red clover also known as Trifolium pratense L., is a perennial allogame plant belonging to Trifolium genus and Fabaceae family. Besides its benefits in animal feed and soil improvement, red clover was studied as well for its medicinal properties, being used in different forms like essential oil, tea, pills and other. This study aimed to perform a comparative analysis on some diploid and tetraploid red clover cultivars regarding morphological and biochemical traits. The study was carried out between 2022 and 2023 on 90 red clover cultivars, divided into two samples represented by diploids and tetraploids. Tetraploids were superior to diploids in the 2nd year and inferior in the 3rd year. Regarding the polyphenols content, diploids showed higher values than tetraploids. Between diploids and tetraploids, there was a significant difference in the number of inflorescences/50g and inflorescence weight from the 3rd year.

Abstract Solanum sisymbriifolium is a shrub native to South America and considered a weed of several important crops. Despite this, this species has proven nematicidal capacity and medicinal properties, due to its ability to produce alkaloids. Thus, the objective of this work was to adjust a reliable protocol to obtain in vitro polyploid plants of S. sisymbriifolium to generate germplasm that serves as the basis for a breeding program of this species aimed to improve the sanitary conditions of horticultural crops with less impact on the environment.

Abstract Rose (Rosa) is a prominent ornamental plant that holds substantial economic and social significance. Roses originating from different regions exhibit intricate phenotypic and genetic characteristics, but the majority of rose genetic resources are poorly characterized. In this study, 192 genotypes of the genus Rosa were examined using 33 phenotypic traits and 10 pairs of SSR markers. Compared to wild species, both old garden and modern roses exhibited a significant level of diversity, with flower color having the highest degree of diversity and style morphology having the lowest degree of diversity. This phenomenon may be attributed to the limited utilization of wild roses due to their simpler ornamental traits and the frequent phenotypic and molecular infiltration between old garden roses and modern roses. Following a inaugural comprehensive evaluation employing principal component analysis, R. chinensis ‘Zihongxiang’, R. hybrida ‘Burgundy Iceberg’, R. hybrida ‘Conrad F. Meyer’, R. rugosa ‘Gaohong’ and R. floribunda ‘Sheherazad’ were selected as core germplasm resources for future breeding. Moreover, three tetraploid roses, namely R. hybrida ‘Midnight Blue’, R. floribunda ‘Sheherazad’, and R. hybrida ‘Couture Rose Tilia’, with significant differences in both phenotypic and molecular profiles were selected and reciprocally intercrossed. Ultimately, two populations were obtained exhibiting significant variation in flower size, annual stem color, stem pickle density, and leaf number. Furthermore, our results indicated that the traits of flower diameter, flower height, petal width, and petal number may potentially be controlled by two major-effect loci. In conclusion, this study provides novel insights into the evolutionary patterns of Rosa germplasm resources. It paves the way for identifying core genotypes that carry distinct ornamental characteristics and possess immense value for breeding novel varieties in the future.

Abstract Experiments were conducted to optimize triploid induction parameters, and assess triploid sterility, in burbot. Duration and timing of shocks were based on degree minutes, temperature multiplied by time, denoted as °C min. Hydrostatic shock experiments investigated the duration of shock using 7500 or 8500 psi at 180°C min post‐fertilization. Thermal shocks investigated duration of shock and post‐fertilization shock timing using a shock of 16°C. Sterility experiments investigated egg survival when diploids were crossed with triploids. Hydrostatic shock of 7500 psi for 10 or 20°C min can induce triploidy ≥90% and exhibits survival that is statistically similar, p ≤ 0.05, to controls. Hydrostatic shock of 8500 psi for 5 or 10°C min yielded triploid induction of 93% and 100%, respectively, with survival that is statistically similar to controls, p ≤ 0.05. Thermal induction experiments indicated shocks at 120°C min post‐fertilization, for durations between 350 and 450°C min, have potential to induce triploidy ≥90% while facilitating survival statistically similar to controls, p ≤ 0.05. Induction of tetraploidy was observed. Sterility experiments determined that triploid burbot are functionally sterile. These results may allow production of burbot where sterility is required.

Abstract Background Artificial induction of polyploidy is the most common and effective way to improve the biological properties of Populus and develop new varieties of this tree. In this study, in order to confirm and expand earlier findings, we established a protocol using colchicine and based on an efficient shoot regeneration system of leaf blades to induce tetraploidy in vitro in three genotypes from diploid Populus hopeiensis. The stomatal characteristics, leaf blade size, and growth were evaluated for diploids and tetraploids of three genotypes. Results We found that genotype, preculture duration, colchicine concentration, and colchicine exposure time had highly significant effects on the tetraploid induction rate. The optimal protocol for inducing tetraploidy in P. hopeiensis was to preculture leaf blades for 7 days and then treat them for 4 days with 40 mg/L colchicine. The tetraploid induction rates of genotypes BT1, BT3, and BT8 were 21.2, 11.4 and 16.7%, respectively. A total of 136 tetraploids were identified by flow cytometry analysis and somatic chromosome counting. The stomatal length, width, and density of leaf blades significantly differed between diploid and tetraploid plants. Compared with their diploid counterparts, the tetraploids produced larger leaf blades and had a slower growth rate. Our findings further document the modified morphological characteristics of P. hopeiensis following whole-genome duplication (e.g., induced tetraploidy). Conclusions We established a protocol for in vitro induction of tetraploidy from diploid leaf blades treated with colchicine, which can be applied to different genotypes of P. hopeiensis.

Passiflora edulis Sims (2n = 18) is a perennial plant with high utilization values, but its spontaneous polyploidy in nature has yet to be seen. Thus, this study aims to enhance our understanding of polyploidy P. edulis and provide rudimentary knowledge for breeding new cultivars. In this study, colchicine-induced tetraploid P. edulis (2n = 36) was used as experimental material (T1, T2, and T3) to explore the variances between it and its diploid counterpart in morphology, physiology, and biochemical characteristics, and a comparison of their performance under cold stress was conducted. We measured and collected data on phenotype parameters, chlorophyll contents, chlorophyll fluorescence, photosynthesis, osmotic substances, and antioxidant enzymes. The results showed that tetraploid P. edulis exhibited a shorter phenotype, more giant leaves, darker leaf color, and longer and fewer roots. Moreover, the physiological and biochemical analysis indicated that the tetraploid P. edulis had better photosynthesis systems and higher chlorophyll fluorescence parameters than the diploid P. edulis. Additionally, the tetraploid P. edulis had higher activity of antioxidant enzymes (SOD, POD, CAT) and lower MDA content to maintain better resistance in low temperatures. Overall, we conclude that there were apparent differences in the morphological, physiological, and biochemical traits of the tetraploid and diploid P. edulis. The tetraploid plants showed better photosynthesis systems, higher osmotic substance content, and antioxidant enzyme activity than the diploid, even under cold stress. Our results suggest that tetraploids with more abundant phenotype variation and better physiological and biochemical traits may be used as a new genetic germplasm resource for producing new P. edulis cultivars.

Phellodendron amurense Rupr. is a precious medicinal tree species in northeast China. However, P. amurense resources have been severely destroyed due to uncontrolled overharvest and the limited innovation of new germplasms by traditional cross-breeding. In this study, polyploid breeding was introduced to the improvement program of P. amurense. Fifty-four tetraploid plants of P. amurense were first produced by colchicine-induced adventitious bud chromosome doubling in stem segment explants. The induction frequency reached 36.16% (1.0 g L−1 colchicine solution for 48 h treatment) and 50.00% (2.0 g L−1 colchicine solution for 24 h treatment), respectively, showing the high efficiency of the somatic chromosome doubling based on the organogenesis system. Tetraploidization resulted in significant phenotypic variation, such as larger and thicker leaves, thicker stems, and bigger stomata. Ultra-performance liquid chromatography–mass spectrometry (UPLC–MS/MS) analysis identified 59 differentially accumulated alkaloids (DAAs) between the leaf and stem samples of tetraploids, including 32 upregulated and 27 downregulated in stems. For both leaf and stem samples, 18 DAAs were identified between diploids and tetraploids, with 16 DAAs upregulated in tetraploid leaves and 8 upregulated in tetraploid stems, suggesting that polyploidization caused significant alterations in alkaloid contents in leaves and stems of P. amurense. The contents of the main medicinal compounds, such as berberine, jatrorrhizine, phellodendrine, and palmatine, increased significantly in the leaf and/or stem samples after polyploidization. This finding implied that polyploid breeding might be an effective approach for improving P. amurense, beneficial to preserving and exploiting natural resources.

Polyploid rice and its reverted diploid show rich phenotypic variation and strong heterosis, showing great breeding value. However, the genomic differences among tetraploids, counterpart common diploids, tetraploid-revertant diploids, and hybrid descendants are unclear. In this work, we bred a new excellent two-line hybrid rice variety, Y Liang You Duo Hui 14 (HTRM12), using Haitian tetraploid self-reverted diploid (HTRM2). Furthermore, we comparatively analyzed the important agronomic traits and genome-wide variations of those closest relatives, Haitian diploid (HT2), Haitian tetraploid (HT4), HTRM2, and HTRM12 in detail, based on multiple phenotypic investigations, genome resequencing, and bioinformatics analysis. The results of agronomic traits analysis and genome-wide variation analysis of single nucleotide polymorphism (SNP), insertion–deletion (InDel), and copy number variation (CNV) show that HT4 and HTRM2 had abundant phenotypic and genomic variations compared to HT2. HTRM2 can inherit important traits and variations from HT4. This implies that tetraploid self-reverted diploid has high potential in creating excellent breeding materials and in breeding breakthrough hybrid rice varieties. Our study verifies the feasibility that polyploid rice could be used as a mutation carrier for creating variations and provides genomic information, new breeding materials, and a new way of application for tetraploid rice breeding.

Unscheduled whole-genome doubling (WGD) events give rise to tetraploid cells that are prone to replication-stress-induced DNA damage, chromosome instability, and oncogenic epigenetic alterations. Proliferating whole-genome doubled cells are tumorigenic and comprise ∼37% of primary and ∼56% of metastatic solid tumors. Whole-genome doubled cancer cells must acquire specific genetic and physiological adaptations to accommodate the unique stresses imposed by their doubled DNA and cellular content. Identifying genes that are essential for the viability of proliferating whole-genome doubled cancer cells, yet dispensable for the viability of diploid cells (i.e., ploidy-specific lethal genes), has the potential to uncover new cancer therapeutics. The overwhelming majority of proliferating somatic human cells are diploid, and this genomic state is typically maintained across successive cell divisions. However, failures in cell division can induce a whole-genome doubling (WGD) event, in which diploid cells transition to a tetraploid state. While some WGDs are developmentally programmed to produce nonproliferative tetraploid cells with specific cellular functions, unscheduled WGDs can be catastrophic: erroneously arising tetraploid cells are ill-equipped to cope with their doubled cellular and chromosomal content and quickly become genomically unstable and tumorigenic. Deciphering the genetics that underlie the genesis, physiology, and evolution of whole-genome doubled (WGD+) cells may therefore reveal therapeutic avenues to selectively eliminate pathological WGD+ cells. [ABSTRACT FROM AUTHOR]

Through artificial polyploid induction, new varieties of horticultural crops with better quality can be generated. Mixed culture was used to induce polyploidy of black currant in this study. Sterile seeds of black currant were treated with different concentrations of colchicine (0.05%, 0.10%, 0.15%, 0.20%) for different lengths of time (8 h, 12 h, 24 h, 36 h, 48 h). The results showed that 0.15% colchicine treatment for 24 h was the best condition for polyploid induction of black currant, and the highest induction rate was 12.0%. The ploidy of seedlings was verified by chromosome counting and flow cytometry. The morphological differences and stomatal characteristics of tetraploid plants and diploid plants were compared. The tetraploid plants were characterized by being dwarfed with shorter internode lengths, having thick stems,t larger and rounder leaves, with decreased stomatal density and larger stomates. Finally, a total of 3246 differentially expressed genes were identified in diploid and tetraploid leaves by transcriptome sequencing analysis, including 615up and 2631down regulated genes. KEGG (Kyoto Encyclopedia of Genes and Genome) pathway analysis showed that 1355 DEGs (Differentially expressed gene) were enriched in 133 metabolic pathways. DEGs were mainly enriched in 'Plant hormone signal transduction' and 'MAPK (Mitogen-activated protein kinase) signaling pathway-plant' pathways, that were related to plant hormones, biotic stress and abiotic stress signal transduction. This study enriched the germplasm resources of black currant, provided a new way for black currant breeding, and provided a theoretical basis for revealing the potential mechanism of tetraploid development. Key message: Successfully induced tetraploid blackcurrant, revealing the difference between tet raploid and diploid blackcurrant plants through physiological characteristics and transcriptome analysis. [ABSTRACT FROM AUTHOR]

Experiments were conducted to optimize triploid induction parameters, and assess triploid sterility, in burbot. Duration and timing of shocks were based on degree minutes, temperature multiplied by time, denoted as °C min. Hydrostatic shock experiments investigated the duration of shock using 7500 or 8500 psi at 180°C min post‐fertilization. Thermal shocks investigated duration of shock and post‐fertilization shock timing using a shock of 16°C. Sterility experiments investigated egg survival when diploids were crossed with triploids. Hydrostatic shock of 7500 psi for 10 or 20°C min can induce triploidy ≥90% and exhibits survival that is statistically similar, p ≤ 0.05, to controls. Hydrostatic shock of 8500 psi for 5 or 10°C min yielded triploid induction of 93% and 100%, respectively, with survival that is statistically similar to controls, p ≤ 0.05. Thermal induction experiments indicated shocks at 120°C min post‐fertilization, for durations between 350 and 450°C min, have potential to induce triploidy ≥90% while facilitating survival statistically similar to controls, p ≤ 0.05. Induction of tetraploidy was observed. Sterility experiments determined that triploid burbot are functionally sterile. These results may allow production of burbot where sterility is required. [ABSTRACT FROM AUTHOR]

Hybrid cultivars are valuable in many crop species due to their high yield, uniformity, and other desirable traits. Doubled haploids, which have two identical sets of chromosomes, are valuable for hybrid breeding because they can be produced in one generation, in comparison to the multigenerational process typically used to produce inbred parents for hybrid production. One method to produce haploid plants is manipulation of centromeric histone H3 (CENH3). This method of producing haploids has so far been successful in Arabidopsis, maize (Zea mays), and wheat (Triticum aestivum). Here we describe modification of CENH3 in carrot (Daucus carota) to test for the ability of these modifications to induce uniparental genome elimination, which is the basis for haploid induction. Base editing was used to make cenh3 mutant plants with amino acid substitutions in the region of CENH3 encoding the histone fold domain. These cenh3 mutant plants were then outcrossed with CENH3 wildtype plants. Using PCR-based genotyping assays, we identified two candidates for genome elimination. One candidate was classified as a putative aneuploid plant in which chromosome 7 is in a single copy state. The other candidate was characterized as a putative tetraploid that was likely haploid during its genesis. Our results suggest that this putative tetraploid inherited all of its chromosomes from the CENH3 wild-type parent and that the genome of the cenh3 mutant plant was lost. This study provides evidence that modification of CENH3 in carrot has the potential to induce genome elimination and ploidy changes in carrot. [ABSTRACT FROM AUTHOR]

With nearly 40 species, the fern genus Notholaena has its evolutionary centre in the deserts of Mexico and the southwestern United States. Previous studies have focused on assessing the monophyly of the genus and the patterns of farina evolution, but little attention has been given to species complexes. Notholaena trichomanoides s.l. is endemic to the Greater Antilles, growing on all four islands. Although at least two varieties have been described, many authors have hesitated to recognize them and have treated this complex as only one taxon. A multivariate morphometric analysis including 80 representatives of N. trichomanoides from the Greater Antilles allowed us to recognize four morphological groups. Twenty individuals from seven populations representing all these morphological groups were sampled in Cuba. Differences among the four lineages were supported by molecular phylogenetics (including three plastid and two nuclear markers), molecular species delimitation, morphology and geological preferences. Ploidy levels inferred using spore sizes calibrated by chromosome counts revealed the existence of diploid and tetraploid lineages within the complex. Time-calibrated trees suggest that the divergence of the common ancestral populations of N. trichomanoides s.l. and those of its sister taxon N. ekmanii occurred between the Middle Miocene and the Miocene–Pliocene boundary followed by a recent diversification within the complex, ranging between the Middle Pliocene and the Middle Pleistocene. [ABSTRACT FROM AUTHOR]

Tartary buckwheat (Fagopyrum tataricum) is a dual-purpose medicinal and food crop grown for its high contents of functional compounds and abundant nutrients. Although studies have shown the differences of total flavonoid content in Tartary buckwheat at different ploidy levels, the composition of flavonoid and its regulatory mechanisms are largely unknown. In this study, the leaf metabolome and transcriptome of diploid and tetraploid accessions of Tartary buckwheat were analyzed to gain insight into the impact of polyploidization on comparative secondary metabolite composition and molecular regulatory mechanism. Based on a widely targeted metabolomics analysis, a total of 792 metabolites were identified, including 127 flavonoids. The accumulation of 127 metabolites and expression of 3871 genes differed significantly between diploid and tetraploid Tartary buckwheat. Integrated metabolomics and transcriptome analysis revealed that chromosome doubling up-regulated the expression of upstream genes in the flavonoid biosynthesis pathway to promote the accumulation of flavonoids. The present results contribute to elucidation of the molecular mechanism of phenotypic variation associated with polyploidy in Tartary buckwheat. The findings provide a reference for further studies on phenotypic traits in polyploid Tartary buckwheat, the cloning of crucial regulatory genes, and utilization of genetic engineering technologies in the breeding of Tartary buckwheat. [ABSTRACT FROM AUTHOR]

Drought-induced forest death has become a global phenomenon, which is hindering the development of sustainable forestry. Polyploidy breeding has been considered as an effective method of genetic improvement for tree stress resistance. However, the response mechanisms of tetraploid poplars to drought stress are unclear. In this study, based on high-throughput sequencing of transcriptome, small RNA, and degradome for these samples, which selected three genotypes of tetraploid poplars and their counterpart diploids for drought stress and rewatering trial in the experiment, we performed multi-omics analyses to investigate the distinction in drought resistance between tetraploid and diploid. A total of 3391 differentially expressed genes (DEGs) were found from the Dro-Di vs. CK-Di, 3753 DEGs from the Re-Di vs. Dro-Di, 3857 DEGs from the Dro-Te vs. CK-Te, and 4177 DEGs from the Re-Te vs. Dro-Te. Of the above DEGs, 1646 common-DEGs were identified significantly related to drought-stress response, 2034 common-DEGs related to rewater response, 158 and 114 common-DEGs showed opposite expression patterns between diploid and tetraploid, implying that these DEGs might play important roles in response to drought stress as a result of differences in ploidy. Additionally, 586 known miRNAs and 72 novel miRNAs were identified through analysis of 18 small RNA libraries, among which eight common-miRNAs were significantly related to drought-stress response, and four were related to rewater response. The degradome sequencing analysis revealed that 154 target transcripts for 24 drought-stress-associated differentially expressed miRNAs (DEmiRs), and 90 for 12 rewatering-associated DEmiRs were identified in the tetraploid based on both degradome and TargetFinder analyses. These findings provide valuable information for further functional characterization of genes and miRNAs in response to drought stress in Populus polyploidy, and potentially contribute to drought-resistant breeding of polypoid in the future. [ABSTRACT FROM AUTHOR]

Under salt stress, recretohalophyte Plumbago auriculata tetraploids enhance salt tolerance by increasing selective secretion of Na+ compared with that in diploids, although the mechanism is unclear. Using non-invasive micro-test technology, the effect of salt gland Ca2+ content on Na+ and K+ secretion were investigated in diploid and tetraploid P. auriculata under salt stress. Salt gland Ca2+ content and secretion rates of Na+ and K+ were higher in tetraploids than in diploids under salt stress. Addition of exogenous Ca2+ increased the Ca2+ content of the salt gland in diploids and is accompanied by an increase in the rate of Na+ and K+ secretion. With addition of a Ca2+ channel inhibitor, diploid salt glands retained large amounts of Ca2+, leading to higher Ca2+ content and Na+ secretion rate than those of tetraploids. Inhibiting H2O2 generation and H+-ATPase activity altered Na+ and K+ secretion rates in diploids and tetraploids under salt stress, indicating involvement in regulating Na+ and K+ secretion. Our results indicate that the increased Na+ secretion rate of salt gland in tetraploids under salt stress was associated with elevated Ca2+ content in salt gland.

Near-infrared spectroscopy (NIR) has become an essential tool for non-destructive analysis in various fields, including aquaculture. This study presents a pioneering application of portable NIR spectrometers to analyze glycogen content in the gonadal tissues of the Pacific oyster (Crassostrea gigas), marking the first instance of developing quantitative models for glycogen in tetraploid C. gigas. The research also provides a comparative analysis with models for diploid and triploid oysters, underscoring the innovative use of portable NIR technology in aquaculture. Two portable NIR spectrometers were employed: the Micro NIR 1700 (908–1676 nm) and the Micro PHAZIR RX (1624–2460 nm). Near-infrared spectra were acquired from the gonadal tissues of diploid, triploid, and tetraploid C. gigas. Quantitative models for glycogen content were developed and validated using cross-validation methods. Additionally, qualitative models for different ploidies and genders were established. For the Micro NIR 1700, the cross-validation correlation coefficients (Rcv) and cross-validation relative predictive errors (RPDcv) for glycogen were 0.949 and 3.191 for diploids, 0.915 and 2.498 for triploids, and 0.902 and 2.310 for tetraploids. The Micro PHAZIR RX achieved Rcv and RPDcv values of 0.781 and 2.240 for diploids, 0.839 and 2.504 for triploids, and 0.717 and 1.851 for tetraploids. The Micro NIR 1700 demonstrated superior quantitative performance, with RPD values exceeding 2, indicating its effectiveness in predicting glycogen content across different ploidy levels. Qualitative models showed a performance index of 91.6 for diploid and 95 for tetraploid genders using the Micro NIR 1700, while the Micro PHAZIR RX achieved correct identification rates of 99.79% and 100% for diploid and tetraploid genders, respectively. However, differentiation of ploidies was less successful with both instruments. This study’s originality lies in establishing the first quantitative models for glycogen content in tetraploid C. gigas using portable NIR spectrometers, highlighting the significant advancements in non-destructive glycogen analysis. The applicability of these findings is substantial for oyster breeding programs focused on enhancing meat quality traits. These models provide a valuable phenotyping tool for selecting oysters with optimal glycogen content, demonstrating the practical utility of portable NIR technology in aquaculture.

Polyploidization produces abundant phenotypic variation. Little is currently known about adventitious root (AR) development variation due to polyploidization. In this study, we analyzed the morphological, cytological, and physiological variations in AR development between tetraploid and diploid Populus plants during in vitro rooting culture. Compared to the diploids, the AR formation times and rooting rates of the tetraploids’ stem explants had non-significant changes. However, the tetraploid ARs exhibited significantly slower elongation growth than the diploid ARs. Cytological observation showed that the tetraploid ARs were characterized by shorter root meristems and reduced meristem cell numbers, suggesting the reasons for the slow AR elongation. Analysis of hormones and related metabolites during AR development demonstrated that the total auxin, cytokinin, and jasmonic acid contents were significantly lower in the tetraploid ARs than in those of the diploids, and that the ratio of total auxins to total CKs at 0 h of AR development was also lower in the tetraploids than in the diploids, whereas the total salicylic acid content of the tetraploids was consistently higher than that of the diploids. qPCR analysis showed that the expression levels of several hormone signaling and cell division-related genes in the tetraploid ARs significantly differed from those in the diploids. In conclusion, the slow elongation of the tetraploid ARs may be caused by the endogenous hormone-mediated meristem shortening. Our findings enhance the understanding of polyploidization-induced variation in AR development of forest trees.

Abstract Background Cymbidium aloifolium is a popular ornamental flower in Thailand with both economic and medical values. Polyploid induction techniques are used to improve plant quality. This study identified polyploidy levels of C. aloifolium induction by colchicine. Protocorms of C. aloifolium were treated on solid New Dogashima Medium (NDM) with various concentrations of colchicine (0, 0.01, 0.02, 0.03, 0.04 and 0.05% w/v) for 2, 4 and 8 weeks. Results Colchicine effectively induced plant polyploidy. Tetraploid plants were found after treatment with 0.03% and 0.04% colchicine for 8 weeks, while at increased concentration and duration, survival, response and growth performance decreased. Tetraploid plants showed the lowest growth performance but highest size of stomatal and epidermal cells. Growth performance and leaf surface anatomy data were analyzed by Pearson’s correlation and PCA. Results showed that stomatal and epidermal cell sizes had strongly negative correlations with other variables, while HCA revealed that stomatal and epidermal cell sizes of tetraploid plantlets were larger but stomatal and epidermal cell densities decreased when compared with the diploids. Conclusion Colchicine at suitable concentrations and duration produced polyploid plants with alteration of morphological and anatomical traits. This study provides potential information to support orchid quality production as ornamental plants and a source of pharmaceutical raw materials.

Tetraploid is a very important experimental material, whether in scientific research or breeding practice. However, tetraploid strains are relatively rare. It was reported that chromosomes allocation disorder during cell division may lead to high embryonic mortality and low fertility in tetraploid fish. In this paper, tetraploid zebrafish is prepared by ploidy operation. And successfully establishes a tetraploid zebrafish cell line in vitro. To tracing status of microtubules, the tetraploid zebrafish cells are transfected with two plasmids of pBLK-α-tubulin-mCherry and pBLK-γ-tubulin-EGFP by electroporation in vitro. Observation shows that these transfected cells can be traced the changes of spindle and centrosomes during cell division in tetraploid cells. The results provide important material platform in vitro for studying the chromosome behavior in tetraploid cell proliferation, especially the formation mechanism of aneuploidy.

Stable neotetraploid lines of lettuce (Lactuca sativa L.) were produced from three phenotypically distinct cultivars (Annapolis, Eruption, Merlot) and an advanced breeding line (SM13-L2) using colchicine treatment of seeds or young seedlings. When tested under the greenhouse and field conditions, neotetraploids initially grew more rapidly than their diploid progenitors, however they reached their reproductive stage (bolting, flower bud formation, and flowering) substantially later. Seeds production on neotetraploids was delayed by more than 30 days compared to diploids. Tetraploid plants had fewer, but larger stomata and leaves, less chlorophyll per area, higher photosystem II photochemical efficiency, generally lighter root system, and produced less than 1% of seeds in comparison with diploids. Field-grown neotetraploids of all lines displayed a significant reduction in tipburn (1.8% vs. 22.2%, respectively), a highly undesirable physiological disorder. Changes in leaf and root mineral composition were detected in neotetraploids. Several elements were found in lower abundance than in diploids, most notably iron, calcium, and silicon. Whole genome bisulfite sequencing (WGBS) revealed 498 differentially methylated regions (DMR), with 106 of these regions having at least 50% difference in the level of methylation between neotetraploids and their diploid progenitors. At least 18 of the most prominent DMR were detected in proximity to genes predicted to be involved in plant development or reaction to biotic and abiotic stressors. Because neotetraploid lines have low seed production, they are not suitable for commercial cultivation. They can be used, however, in research to study the factors contributing to tipburn, traits affected by stomata size or density, and the effect of ploidy on resistance to environmental stressors.

Hybrid cultivars are valuable in many crop species due to their high yield, uniformity, and other desirable traits. Doubled haploids, which have two identical sets of chromosomes, are valuable for hybrid breeding because they can be produced in one generation, in comparison to the multigenerational process typically used to produce inbred parents for hybrid production. One method to produce haploid plants is manipulation of centromeric histone H3 (CENH3). This method of producing haploids has so far been successful in Arabidopsis, maize (Zea mays), and wheat (Triticum aestivum). Here we describe modification of CENH3 in carrot (Daucus carota) to test for the ability of these modifications to induce uniparental genome elimination, which is the basis for haploid induction. Base editing was used to make cenh3 mutant plants with amino acid substitutions in the region of CENH3 encoding the histone fold domain. These cenh3 mutant plants were then outcrossed with CENH3 wild-type plants. Using PCR-based genotyping assays, we identified two candidates for genome elimination. One candidate was classified as a putative aneuploid plant in which chromosome 7 is in a single copy state. The other candidate was characterized as a putative tetraploid that was likely haploid during its genesis. Our results suggest that this putative tetraploid inherited all of its chromosomes from the CENH3 wild-type parent and that the genome of the cenh3 mutant plant was lost. This study provides evidence that modification of CENH3 in carrot has the potential to induce genome elimination and ploidy changes in carrot.

Tetraploid complementation is an ideal method for demonstrating the differentiation potential of pluripotent stem cells. In this study, we selected the most efficient tetraploid production method for porcine embryos and investigated whether tetraploid blastomere aggregation could enhance the quality of tetraploid embryos. Three methods were investigated to produce tetraploid embryos: First, tetraploid embryos were produced using electro-fusion of two-cell stage parthenogenetic blastomere (FUTP). Second, somatic cell was injected into the mature oocyte and fused to produce tetraploid embryos. Third, oocytes were matured with Cytochalasin B (CB) for the late 22 h of in vitro maturation to inhibit the first polar body (PB1). Following that, non-PB1 oocytes were treated with CB for 4 h after parthenogenetic activation. There was no significant difference in the blastocyst development rate and tetraploid production rate of the embryos produced through the three methods. However, FUTP-derived blastocysts had a significantly lower percentage of apoptotic cells compared to other methods. The developmental competence of embryos, expression of trophectoderm cell marker genes, and distribution of YAP1 protein were investigated in tetraploid embryos produced using the FUTP method. The FUTP method most effectively prevented apoptosis during porcine tetraploid embryo formation. Tetraploid aggregation-derived blastocysts have a high proportion of trophectoderm with increased expression of the CDX2 mRNA and high YAP1 intensity. High-quality blastocysts derived from a tetraploid embryo aggregation can serve as suitable source material for testing the differentiation potential of pluripotent stem cells for blastocyst complementation in pigs.

Tetraploidy is a hallmark of broad cancer types, but it remains largely unknown which aspects of cellular processes are influenced by tetraploidization in human cells. Here, we found that tetraploid HCT116 cells manifested severe cell shape instability during cytokinesis, unlike their diploid counterparts. The cell shape instability accompanied the formation of protrusive deformation at the cell poles, indicating ectopic contractile activity of the cell cortex. While cytokinesis regulators such as RhoA and anillin correctly accumulated at the equatorial cortex, myosin II was over-accumulated at the cell poles, specifically in tetraploid cells. Suppression of myosin II activity by Y27632 treatment restored smooth cell shape in tetraploids during cytokinesis, indicating dysregulation of myosin II as a primary cause of the cell shape instability in the tetraploid state. Our results demonstrate a new aspect of the dynamic cellular process profoundly affected by tetraploidization in human cells, which provides a clue to molecular mechanisms of tetraploidy-driven pathogenic processes. • HCT116 cells show drastic cell shape instability during cytokinesis, specifically in the tetraploid state. • Myosin II over-accumulates at the polar cortex in a tetraploidy-specific manner. • Pharmacological suppression of myosin II restores cell shape instability in tetraploid cytokinesis cells. [ABSTRACT FROM AUTHOR]