Integrative Genomic and Cytogenetic Analyses Reveal the Landscape of Typical Tandem Repeats in Water Hyacinth
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 (<i>Pontederia crassipes</i> or <i>Eichhornia crassipes</i>) remain larg...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-06-01
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| Series: | Horticulturae |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2311-7524/11/6/657 |
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| Summary: | 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 (<i>Pontederia crassipes</i> or <i>Eichhornia crassipes</i>) 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. |
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| ISSN: | 2311-7524 |