Search Results (512)

Cryptochromes (CRYs), as essential blue-light photoreceptors, play pivotal roles in modulating plant growth, development, and stress responses. Although CRY-mediated light signaling has been extensively studied in model species, their functions remain limited in wheat. In this work, a comprehensive analysis of the TaCRY gene family was performed in wheat, identifying 12 TaCRY members localized to distinct chromosomes 2, 6, and 7. TaCRYs contain the conserved PHR and CCT domains and diverse gene structures. Collinearity relationships indicated their dynamic evolution patterns during polyploidization. Cis-acting elements of TaCRY members associated with light responsiveness, phytohormone signaling, and abiotic stress were also identified. Transcriptome analysis revealed that the differential expression patterns of TaCRY members under seed vigor process. This study expands our understanding of TaCRY diversity and provides valuable molecular information for marker-assisted selection in wheat improvement. Full article

Longshan Lilium lancifolium is a well-known medicinal and edible lily and has been registered as a geographical indicator in China. Polyploidization confers many advantages in lily production; however, characteristics of Longshan L. lancifolium improved by polyploidization have not been reported. Here, polyploidization was induced in regenerated Longshan L. lancifolium shoots using colchicine, and the mutant plantlets were characterized by morphological observation, flow cytometry, and inter simple sequence repeat (ISSR) marker technology. The optimal medium for inducing shoot regeneration was Murashige and Skoog (MS) media supplemented with 0.2 mg/L of naphthaleneacetic acid (NAA) and 0.4 mg/L of thidiazuron (TDZ). The greatest mutation induction effect was obtained after soaking the regenerated shoots in 0.10% colchicine for 48 h, for an 80.00% frequency of morphological variants. Forty-one mutant plantlets were subjected to flow cytometry, identifying one homozygous polyploid, ‘JD-12’, and one chimeric polyploid, ‘JD-37’. Additionally, 68 chromosomes were found in the ‘JD-12’ root tip cells. Compared with the control, both the tissue-cultured and field-generated ‘JD-12’ plantlets presented a slight decrease in plant height, a darker green leaf color, a rougher leaf surface, and a larger bulblet diameter; furthermore, the upper epidermal and guard cells of ‘JD-12’ were much larger with a significantly lower stomatal density. The ISSR marker detection indicated a genetic variation rate of 6.10% in ‘JD-12’. These results provide a basis for lily polyploidization breeding and the cultivation of superior Longshan L. lancifolium via shoot regeneration. Full article

Polyploidy plays a significant role in loquat breeding, particularly in triploid breeding for seedless fruit production. Currently, loquat polyploid breeding primarily relies on natural seedling selection and sexual hybridization approaches. In this study, unfertilized ovules from four loquat varieties were in vitro cultured. Gynogenesis and embryoid regeneration were achieved in ‘Xingning 1’ and ‘Huabai 1’, with ‘Xingning 1’ demonstrating the highest gynogenesis efficiency (21.63%). Flow cytometry and chromosome counting revealed that the obtained embryoid lines included haploid, diploid, tetraploid, hexaploid, and chimeric ploidy types. Further characterization of ‘Xingning 1’-derived embryoid lines through SSR markers and whole-genome resequencing confirmed that the haploid, diploid, tetraploid, and hexaploidy embryoid originated from haploid–somatic chimeras, diploid, doubled diploid and tripled diploid, respectively. Metabolic analysis showed a positive correlation between ploidy level and the content of both soluble sugars and organic acids. This study explored a novel platform for polyploid induction in loquat and may provide methodological insights for improvement of other perennial fruit trees. Full article

Interspecific and intersectional crosses have introduced valuable genetic traits for blueberry (Vaccinium sect. Cyanococcus) cultivar improvement. Introgression from Vaccinium species at the diploid, tetraploid, and hexaploid levels has been found in cultivated blueberries. Continued efforts to integrate wild blueberry genetic resources into blueberry breeding are essential to broaden the genetic diversity of cultivated blueberries. However, performing heteroploid crosses among Vaccinium species is challenging. Polyploid induction through tissue culture has been useful in bridging ploidy barriers. Mixoploid or chimeric shoots often are produced, along with solid polyploid mutants. These chimeras are mostly discarded because of their genome instability and the difficulty in identifying periclinal mutants carrying germline mutations. Since induced polyploidy in blueberries often results in a low frequency of solid mutant lines, it is important to recover solid polyploids through chimera dissociation. In this study, two vegetative propagation methods, i.e., axillary and adventitious shoot induction, were evaluated for their efficiency in chimera dissociation. Significantly higher rates of chimera dissociation were found in adventitious shoot induction compared to axillary shoot induction. Approximately 89% and 82% of the adventitious shoots induced from mixoploid lines 145.11 and 169.40 were solid polyploids, respectively, whereas only 25% and 53% of solid polyploids were recovered through axillary shoot induction in these lines. Effective chimera dissociation provides useful and stable genetic materials to enhance blueberry breeding. Full article

N¹-methyladenosine (m¹A) serves as a critical regulatory modification in plant mRNA. In Arabidopsis, the TRM61/TRM6 complex functions as m¹A58 methyltransferase writers essential for organogenesis, reproduction, and hormonal signaling. However, the evolutionary dynamics of the TRM61/TRM6 complex across plant lineages remain poorly understood. In this study, we systematically identified TRM6 and TRM61 homologs across 306 plant species and uncovered the conserved evolutionary trajectories between them. These two methyltransferase subunits retain conserved structural motifs, respectively, and exhibit coordinated expression patterns in plants. In wheat (Triticum aestivum L.) and its progenitors, TRM6 and TRM61 proteins demonstrate polyploidization-associated evolutionary coordination. Their promoters harbor stress-, light-, and hormone-responsive cis-elements. Furthermore, the TRM6 and TRM61 genes in wheat exhibit diverse expression profiles across developmental tissues and under abiotic stress conditions. The differences in allelic frequency among TRM6 and TRM61 variants between wild and domesticated wheat populations suggest that they may have undergone selection during wheat domestication and improvement. This study provides an evolutionary framework for the TRM61/TRM6 complex. Full article

Tandem repeats in eukaryotic genomes exhibit intrinsic instability that drives rapid evolutionary diversification. However, their evolutionary dynamics in allopolyploid species such as the water hyacinth (Pontederia crassipes or Eichhornia crassipes) remain largely unexplored. Our study used integrated genomic and cytogenetic analyses of this allotetraploid species to characterize five representative tandem repeats, revealing distinct genomic distribution patterns and copy number polymorphisms. The highly abundant centromeric tandem repeat, putative CentEc, was co-localized with the centromeric retrotransposon CREc, indicating conserved centromeric architecture. Remarkably, putative CentEc sequences showed high sequence conservation (91–100%) despite subgenome divergence, indicative of active concerted evolution. Fluorescence in situ hybridization (FISH) analysis showed ubiquitous telomeric repeats across all chromosomes, while an interstitial chromosome region tandem repeat (ICREc) displayed chromosome-specific localization, both exhibiting copy number variation. Furthermore, differential rDNA organization was observed. 5S rDNA was detected on a single chromosome pair, whereas 35S rDNA exhibited multichromosomal distribution with varying intensities. A comparative analysis of subgenome-specific rDNA sequences revealed substantial heterogeneity in both 5S and 35S rDNA units, suggesting subgenome-biased evolutionary trajectories. Collectively, these findings elucidate the structural and evolutionary significance of tandem repeats in shaping the water hyacinth genome, highlighting mechanisms of concerted evolution and subgenome-biased adaptation in invasive polyploids. Full article

This study investigated the effects of oryzalin treatments on the induction of polyploids and variants, as well as their subsequent morphological and physiological characteristics, in Lysimachia xiangxiensis, a perennial herbaceous plant belonging to the Primulaceae family that is known for its ornamental value. A total of 52 of the 162 treated stem segments survived after treatments and further developed into plantlets, and significant morphological changes in leaf color and growth status were observed. Using flow cytometry and chromosome counting, plants are categorized into the three variant types (VT1, VT2, and VT3), that is, VT1 and VT2 were diploid aneuploids, while VT3 was triploid. The optimized polyploid induction scheme involved treatment with 0.001% oryzalin for 4 days, resulting in an induction rate of up to 100%. Higher concentrations and longer exposure durations resulted in lower survival and polyploid induction rates of all stem segments during the above-mentioned processing. Observation of morphological features indicated that triploid VT3 vines were longer, with larger and thicker leaves and more guard cells, but lower stomatal density, compared with diploid aneuploids or the wild type. Polyploids outperformed other types in terms of chlorophyll content, net photosynthesis rate, stomatal conductance, and intercellular CO₂ concentration, but had a lower flavonoid content. The results demonstrate that oryzalin can effectively induce polyploidy and variants in L. xiangxiensis, resulting in beneficial changes in morphology and physiological characteristics; this should provide valuable insight into the improvement of excellent varieties in plants. Full article

The Chinese jujube (Ziziphus jujuba Mill.), an economically significant fruit tree native to China, is valued for both fresh and dried uses. In plants, 2n gametes serve as the fundamental basis for creating a sexual polyploid germplasm. This study investigated the 2n gametogenesis frequency in triploid hybrid jujubes through meiotic analysis of the hybrid strain Q161 and a two-year pollen analysis on hybrid progeny, assessing the natural 2n pollen frequencies to identify a high-2n-pollen germplasm and revealing the occurrence of 2n pollen. Meiotic analysis of the triploid hybrid Q161 (2n = 36) revealed cytological anomalies, including binucleate cells (22.80% abnormal tetrads), with natural 2n pollen production rates reaching 4.00% and 4.67% over two consecutive years. Scanning electron microscopy (SEM) revealed that the 2n pollen exhibited pronounced exine ornamentation with cerebroid sculpturing and tubercle-like structures at the apertures. Analysis of the triploid progeny for two consecutive years demonstrated a pollen viability of 30.45% and 23.83% (CV: 19. 39–29.69%), with the mean 2n pollen frequencies of 22.52% and 7.64%, peaking at 52.16% and 28.95% in elite individuals. Six triploid germplasm accessions with naturally elevated 2n pollen frequencies were identified. Under natural conditions, a triploid hybrid germplasm in Chinese jujube produces 2n pollen grains due to abnormal meiotic behavior, and a natural triploid germplasm with high pollen productivity was identified. This research provides a critical theoretical foundation for sexual polyploid breeding strategies. Full article

Polyploidization has been one of the key drivers of plant evolution, profoundly influencing plant adaptation in nature and crop traits in agriculture. Deciphering polyploid genomes is a crucial step for understanding evolutionary history and advancing agricultural applications. However, the inherent complexity of polyploid genomes has long hindered accurate assembly and annotation. Recent advances in sequencing technologies and improved assembly algorithms have significantly enhanced the resolution of complex polyploid genomes. These innovations have led to the successful assembly and public release of an increasing number of high-quality polyploid plant genomes. This review summarizes the mechanisms of polyploid formation and their evolutionary relevance, with a focus on recent technological progress in sequencing and genome assembly. On this basis, we further discuss the current key challenges of polyploid genome assembly and the ways to address them. Full article

The possible origin of four cultivated species of the genus Avena of different ploidy and different subgenome composition (A. strigosa, A. abyssinica, A. byzantina, and A. sativa) from possible wild species was investigated. The region of the internal transcribed spacer ITS1 and the 5.8S rRNA gene in the cultivated species was studied with next-generation sequencing (NGS), and the patterns of occurrence and distribution of the ribotypes were compared among them and with those of the wild species. According to these data diploid, A. strigosa is more closely related to the diploid A. hirtula than to polyploid oats, and it could have evolved independently of polyploid cultivated species. The tetraploid Avena abyssinica could be a cultivated derivative of A. vaviloviana. Two hexaploid cultivated species, A. byzantina and A. sativa, could have a different origin; A. sativa could be the cultivated form of A. fatua, whereas A. byzantina could originate independently. It was found that the oat species with the A and C subgenomes, even with strong morphological and karyological differences, could intercross and pass the further stages of introgression producing a new stable combination of genomes. Our data show that almost all species of Avena could form an introgressive interspecies complex. Full article

In the field of fish genetic breeding, accurately determining the DNA content and ploidy of fish is of great significance. This article introduces the use of flow cytometry (FCM) to measure the DNA content and conduct ploidy analysis by sampling different tissues of freshwater fish species. It describes the FCM detection methods and their effectiveness for different individual tissues. These tissues include embryos and fry, as well as the blood, caudal fins, and sperm of adult live fish, and also specific tissues such as testes, ovaries, gills, spleens, and livers under anatomical conditions. Moreover, the application of ploidy detection to different tissues or individuals in different stages in the practice of fish genetic breeding is analyzed. This research covers samples from different growth stages and a variety of tissue types. The results show that this method exhibits high stability and reliability in the detection of different tissue samples, providing solid data support for subsequent research. It holds significant application value in fish genetic breeding. Full article

Botiidae is a small family of freshwater fishes distributed across Southeast Asia, South Asia, and East Asia. It comprises two subfamilies: the diploid Leptobotiinae and the tetraploid Botiinae. Whether species in the Botiinae are autotetraploids or allotetraploids and how many polyploidization events occurred during the evolution of this subfamily remain open questions. The phylogenetic relationships and biogeography of the Botiidae also require further investigation. In the current study, we compared phylogenetic trees constructed using DNA sequences from the mitochondrial genome and five phased nuclear genes. We also performed whole genome sequencing for two tetraploid species: Chromobotia macracanthus and Yasuhikotakia modesta. Genome profiling of five botiine species suggests that they are likely of allotetraploid origin. Nuclear gene tree topologies indicate that the tetraploidization of the Botiinae occurred only once in the common ancestor of this subfamily. Although the possible maternal progenitor and paternal progenitor of the Botiinae cannot be determined, the subfamily Leptobotiinae can be excluded as a progenitor. The gene trees built in this study generally agree on the following sister group relationships: Leptobotiinae/Botiinae, Leptobotia/Parabotia, Chromobotia/Botia, Yasuhikotakia/Syncrossus, and Sinibotia/Ambastaia. Clades formed by the last two generic pairs are also sisters to each other. Timetree analyses and ancestral range reconstruction suggest that the family Botiidae might have originated in East Asia and Mainland Southeast Asia approximately 51 million years ago and later dispersed to South Asia and the islands of Southeast Asia. Full article

Aneuploidy-related disruptions are generally tolerated in polyploid plants, which exhibit a greater capacity for genomic compensation. In this study, we utilize allotetraploid Brassica napus as a model and generated three aneuploid variants (NC1, NC2, and NC8) to investigate the phenotypic and transcriptional consequences of chromosome loss. Significant phenotypic variations were observed, with the most notable being a marked dwarfing phenotype in the aneuploid materials compared to the euploid Oro. Transcriptomic analysis revealed widespread alterations in gene expression across the entire genome in the deficient variants. Notably, most of the differentially expressed genes (DEGs) were attributed to trans-acting effects resulting from the deletion of C chromosomes. Deletion of the C chromosomes induced gene expression changes not only on the corresponding chromosomes, but also on the affected genes across other chromosomes. Specifically, in the C1-deleted variant, the average gene expression of the A1 chromosome increased, while the number of expressed genes on other chromosomes decreased. In contrast, for C2 and C8 deletions, the average expression levels of homologous genes decreased, but the number of expressed genes on other chromosomes increased. These findings shed light on the complex compensatory mechanisms that underlie aneuploidy in polyploid plants and provide valuable insights into how plants maintain genomic stability despite chromosomal loss. Full article

The production of carrot (D. carota L.) doubled haploids (DH) for the acceleration of this important vegetable crop breeding requires genome doubling of haploid regenerants. If spontaneous doubling does not occur, artificial chromosome doubling can be complicated by the lack of efficient genome-doubling protocols. We tested an antimitotic agent treatment of carrot at the embryo stage. It allowed us to produce and treat a large number of clonal carrot embryos (at least 30 embryos per treatment condition) in small volumes with minimal reagent amounts. We showed that 0.01–1 g/L colchicine did not perturb carrot development. Trifluralin showed no signs of toxicity at 0.001 and 0.01 g/L concentrations, but 0.1 g/L trifluralin reduced survival by 40% and delayed plantlet regeneration. We showed via DNA content flow cytometry that 0.01–1 g/L colchicine and 0.001–0.1 g/L trifluralin could double the carrot genome. The highest diploid percent was observed at 1 g/L colchicine (34%) and 0.1 g/L trifluralin (28%). The highest percent of diploids together with mixoploids (partial diploids) was at 0.01 and 0.1 g/L trifluralin (over 70%), followed by 1 g/L colchicine (56%). To our knowledge, this is the first report on trifluralin application for genome doubling in Apiaceae. In our study, we determined colchicine and trifluralin toxicity and doubling efficiency at different concentrations that can be used for carrot DH-line production and further improvement of genome doubling methods. Full article