Epigenetic Regulation of Divergent Co-Expression Between Whole-Genome Duplication and Transposed Duplication Genes and Its Impact on Catechin Accumulation in Camellia sinensis
This study systematically characterizes multi-omics association patterns related to duplicate gene co-expression divergence, providing insights into potential hierarchical regulation and candidate targets for metabolite-directed breeding.
Abstract
Background/Objectives: Whole-genome duplication (WGD) and transposed duplication (TRD) are two principal evolutionary drivers of plant genome expansion, yet the molecular mechanisms underlying their divergent co-expression patterns remain poorly characterized. Methods: In this study, based on the reference genome of tea plant (Camellia sinensis ‘Yunkang 10’, YK10), we integrated publicly available transcriptomic, ATAC-seq, H3K27ac ChIP-seq, whole-genome bisulfite sequencing (WGBS), and SNP data from eight tissues and performed a multi-layered analysis of co-expression divergence across 4071 WGD and 10,174 TRD gene pairs. Results: WGD gene pairs exhibited significantly higher co-expression rates (44.3%) than TRD pairs (33.0%), with gene length and sequence similarity jointly promoting co-expression. Chromatin accessibility and H3K27ac modification were each positively correlated with expression and co-expression; however, under equivalent chromatin accessibility conditions, TRD gene expression remained systematically attenuated, and this reduced expression state was significantly associated with elevated levels of CG, CHG, and CHH methylation, suggesting that these epigenetic marks may collectively participate in the transcriptional repression of TRD genes. Promoter-proximal SNPs exerted disproportionately deleterious effects on TRD co-expression, demonstrating that the combined effects of genetic variation and epigenetic modifications are associated with enhanced transcriptional divergence. Weighted gene co-expression network analysis (WGCNA) revealed that WGD modules showed significant associations with EC, GC, and EGC accumulation, whereas WRKY and bHLH transcription factors in the TRD MEblue module exhibited strong associations with EGCG and ECG. Conclusions: This study systematically characterizes multi-omics association patterns related to duplicate gene co-expression divergence, providing insights into potential hierarchical regulation. It offers mechanistic clues for catechin metabolic regulation and provides candidate targets for metabolite-directed breeding.
Background: Domain of Unknown Function 1645 (DUF1645) is a conserved but poorly characterized plant gene family whose evolutionary history and roles in stress adaptation remain unclear. We performed an integrated genomic, evolutionary, transcriptomic, and Quantitative Trait Locus (QTL) characterization of the DUF1645 family in rice (Oryza sativa). Methods and Results: We identified 14 intronless, non-redundant OsDUF1645 genes distributed across eight chromosomes. Phylogenetic and collinearity analyses suggested that family expansion within Poaceae involved ancestral segmental and localized tandem duplication events. Promoter analysis identified stress- and phytohormone-responsive cis-acting elements, including ABRE, MBS, and MeJA-associated motifs. Public transcriptome datasets revealed diverse OsDUF1645 expression patterns under abiotic and hormonal treatments. Integration with the Quantitative Trait Loci Annotation Rice Online (Q-TARO) QTLome identified physical co-localization of multiple OsDUF1645 loci with stress- and agronomic-trait QTLs, including salinity-, drought-, root architecture-, and water-deficit-associated regions. On Chromosome 1, OsDUF1645.1, OsDUF1645.2, OsDUF1645.3, and OsDUF1645.4 overlapped QTL intervals associated with salinity-related physiological traits, including Na+ uptake and Na+ balance, and drought-related root traits. On Chromosome 5, the tandemly arranged OsDUF1645.8, OsDUF1645.9, and OsDUF1645.10 co-localized with QTLs related to root architecture and water-deficit responses. qRT-PCR validation under salinity, osmotic stress, and cadmium exposure confirmed distinct stress-responsive expression profiles; OsDUF1645.6 exhibited broad multi-stress responsiveness, whereas OsDUF1645.3 was downregulated under several conditions. Conclusions: The OsDUF1645 family exhibits substantial functional diversification, supported by distinct regulatory architectures, expression profiles, and QTL associations. These findings provide a framework for prioritizing OsDUF1645 candidates for functional validation and their potential application in molecular breeding and development of climate-resilient rice cultivars.
Peipei Su, Zhi-Qun Que, Xin Song et al.· Genes· 0 citations
Long intergenic non-coding RNAs (lincRNAs) are key epigenetic regulators of genome function, yet their evolutionary dynamics following whole-genome duplication (WGD) events remain poorly understood. Salmonids, which underwent a lineage-specific autotetraploidization (salmonid-specific WGD, ~88–100 million years ago), provide an excellent model to investigate the retention, divergence, and functional potential of recently duplicated non-coding elements. LincRNA repertoires were compared across five genome-annotated salmonids (Oncorhynchus tshawytscha, O. kisutch, O. mykiss, Salmo salar, and S. trutta) and their closest non-duplicated relative, northern pike (Esox lucius). LincRNAs represented ~5–7% of annotated genes in all salmonids except S. salar (18%). Sequence conservation was low relative to coding genes, with only 11–68 highly similar (e-value < 1 × 10−30; similarity > 70% and alignments > 100 nucleotides) putative orthologues shared between salmonids and northern pike, and 161–338 among salmonids alone. Synteny conservation was modest in lincRNAs, with lower conservation in putative orthologues (8–16%) compared to putative ohnologues (8–33%). Secondary structure conservation was associated with sequence similarity (ρ = −0.45; p = 2.2 × 10−16), and the association was stronger among WGD ohnologues than orthologues. In S. salar and O. mykiss, lincRNA putative ohnologues showed weaker expression correlations than coding genes, suggesting widespread regulatory divergence, possibly through neo- and subfunctionalisation. Conserved salmonid lincRNAs showed enriched predicted interactions with miRNAs involved in tumour suppression, brain, bone, and muscle development (e.g., miR-455, miR-365, miR124, miR-133a, miR-140, and miR-9), a finding supported by limited transcriptomic data. Although salmonid WGD expanded lincRNA repertoires, lincRNAs have undergone rapid sequence and transcriptional divergence, with limited conservation across species based on sequence similarity, chromosomal position, synteny, and secondary structure. A subset of conserved lincRNAs retains structural features and regulatory signatures consistent with roles as miRNA sponges in brain, skeletal, and muscle development and tumour suppression, potentially acting within conserved regulatory networks. These findings provide new insights into lincRNA evolution following genome duplication and highlight the need for experimental validation of their regulatory functions.
Isabel García-Pérez, D. García de la Serrana· International Journal of Mol...· 0 citations
A comprehensive pan-genomic view of structural variation, evolutionary patterns, and expression regulation in the ZmCYP450 family is provided, offering a foundation for future functional studies and maize trait improvement.
Weijian Qi, Jingcheng Wang, Jianzhong Chang et al.· Frontiers in Plant Science· 0 citations
Basic leucine zipper (bZIP) transcription factors regulate plant development and stress responses, but their genus-wide diversity in Populus remains unclear. We analyzed 19 Populus genomes and retained 1764 bZIP proteins, including 21 independent new loci and four annotation corrections. Of these, 1762 were assigned to 79 orthologous gene groups (OGGs), comprising 43 core, 20 soft-core, 15 shell and one cloud OGG, of which 59 showed copy-number variation. Phylogenetic analysis assigned 74 representative pangenes to 13 subfamilies, with five remaining unclassified and motif patterns differing among subfamilies. Whole-genome duplication (WGD)/segmental duplication accounted for 81.0% of OGG-assigned proteins and contributed predominantly to the conserved component. Although 72.2% of bZIP proteins overlapped a transposable element within the gene body or 2-kb flanks, this proportion was modestly lower than in matched non-bZIP genes, and copy-number-variable OGGs showed no greater TE coverage than invariant OGGs. Among retained homologous comparisons, 97.6% had Ka/Ks ≤ 1, supporting predominant purifying selection. Across the heterogeneous public salt-stress RNA-seq datasets analyzed, no OGG showed a significant, directionally concordant response in at least two Populus taxa. These results reveal a conserved bZIP framework shaped mainly by ancient duplication alongside variable genomic contexts and transcriptional responses.
Whole-genome duplication (WGD) is a major driver of plant speciation and often hypothesized to promote rapid adaptation to new or changing environmental conditions. However, the extent to which WGD per se fosters phenotypic and transcriptional novelties, and the relative contribution of WGD-induced changes vs post-WGD evolution to trait differentiation between cytotypes remains poorly understood. Here, we investigated the phenotypic and transcriptomic consequences of WGD and subsequent evolution in the Biscutella laevigata diploid-autotetraploid complex by comparing replicated diploid, synthetic autotetraploids, and natural autotetraploids (originated some 24,000 to 7,000 generations ago) under moderate daily temperature fluctuations (stable) vs. daily heat stress (changing) conditions. WGD led to reduced specific leaf area and slower rosette growth but had no significant effect on biomass. Post-WGD evolution acted in contrasting directions on WGD-induced changes, either reverting traits to diploid-like values or maintaining them in natural autotetraploids. Overall, WGD induced a decrease in fitness that was mitigated by post-WGD evolution, resulting in natural autotetraploids with similar or higher fitness under changing conditions than diploids. While the genetic background modulates the effects of WGD, cytotype-level transcriptomic analyses revealed limited immediate effects of WGD under stable conditions, although heat stress induced different responses across cytotypes. Altogether, our results highlight a complex interplay between immediate WGD-induced and subsequent evolution at the phenotypic and transcriptomic levels, supporting a predominant role of post-WGD evolution in the differentiation of current cytotypes and the adaptive evolution of autotetraploids of B. laevigata.
Sandra Grünig, R. R. Choudhury, C. Parisod· Proceedings of the National...· 0 citations
This study systematically characterizes the composition, expansion and stress response patterns of the GmATG gene family, revealing functional differentiation among family members.
