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Genome-wide identification and expression profiling of the MADS-box gene family in Lavandula angustifolia.

BACKGROUND: MADS-box genes encode transcription factors critical for plant development, particularly floral organogenesis, flowering time regulation, and adaptation to environmental stresses. Among these, the MIKCC-type genes are pivotal regulators in floral developmental processes. Although the evolutionary diversification and functional dynamics of MADS-box genes have been extensively characterized in model plants such as Arabidopsis thaliana and Oryza sativa, their evolutionary relationships and functional profiles in Lavandula angustifolia, an economically significant aromatic plant, remain poorly understood. RESULTS: Genome-wide analysis identified 173 MADS-box genes in L. angustifolia, categorized into type I (Mα: 26; Mβ: 0; Mγ: 10) and type II (MIKCC: 125; MIKC*: 12) based on phylogenetic comparisons with A. thaliana. The MIKCC subgroup was further subdivided into 12 subclasses, including genes central to the ABCDE model of floral organ specification. Structural analyses revealed distinct conserved motifs and exon-intron configurations specific to each subgroup, indicative of functional divergence. Synteny analysis demonstrated Whole Genome Duplication (WGD) and segmental duplications as major contributors to MIKCC gene family expansion, notably among genes linked to floral organ development. Expression profiling via RNA-seq and quantitative real-time PCR (qPCR) showed type II MADS-box genes exhibited higher expression levels with pronounced tissue-specific and developmental stage-specific expression patterns compared to type I genes. Many type II genes displayed significant associations with floral organogenesis, floral transition, and abiotic stress responses, underscoring their essential roles in reproductive development and environmental adaptability in L. angustifolia. CONCLUSIONS: The identification and comprehensive characterization of 173 MADS-box genes in L. angustifolia highlight the significant expansion of the MIKCC subgroup driven primarily by WGD and segmental duplications. The distinct structural features and specific expression patterns observed provide insights into the functional divergence and complexity of these genes, particularly regarding floral organogenesis and adaptation to environmental stress. This study establishes a robust molecular basis for further functional analysis and genetic improvement of aromatic plants.

MADS Domain Proteins↗

Evidence for an ancient whole-genome duplication event in rice and other cereals.

Gene duplication has been proposed as an accelerator of evolution. Ancient genome duplication events have been identified in diverse organisms, such as yeast, vertebrates, and Arabidopsis. Here, we have identified a whole genome duplication event (WGD) in the rice genome, which took place prior to the divergence of grasses about 70 million years ago (mya). A total of 117 duplicated blocks were detected, which are distributed on all 12 chromosomes and cover about 60% of the rice genome. About 20% genes on these duplicated segments are retained as duplicate pairs. In contrast, 60% of the transcription factor genes are retained as duplicates. The identification of a WGD in the ancestral grass genome will impact the study of grass genome evolution, and suggest that polyploidization and subsequent gene losses and chromosomal rearrangements have played an important role in the diversification of grasses.

Edible Grain↗

Chromosome-scale genome remodeling in tumor evolution: Copy number alterations and structural variants as two sides of the same coin.

Chromosome-scale genomic rearrangements are a dominant force in tumor evolution. Copy-number alterations (CNAs) and structural variants (SVs) constitute two complementary axes of this process. Although detection technologies now deliver near-comprehensive catalogs, technical resolution has outpaced conceptual integration. In this review, we frame CNAs and SVs as inextricable facets of chromosomal aberrations. They reshape cancer genomes through altered gene dosage and three-dimensional regulatory rewiring. CNAs quantify the gene-dosage imbalance, yet arise through mechanistically distinct routes. Segmental CNAs typically require chromosomal breakage, and therefore often coincide with SV junctions. By contrast, whole-chromosome aneuploidy and whole-genome doubling (WGD) primarily reflect mitotic or cytokinetic failure and can occur without local breakpoints, while nevertheless reshaping the karyotypic landscape and seeding subsequent structural complexity. SVs, in turn, range from unbalanced events that alter copy number to ostensibly balanced exchanges that predominantly rewire regulatory architecture. Despite their diverse and sometimes catastrophic architectures, SVs are ultimately rooted in double-strand break formation and error-prone resolution. By integrating CNAs and SVs within a unified mechanistic and functional framework, we aim to convert catalogs into concepts and distill the organizing principles that govern tumor genome evolution.

Humans↗

The telomere-to-telomere genome of Sanicula chinensis unveils genetic underpinnings of low furanocoumarin diversity and content in one basal lineage of Apiaceae.

Furanocoumarins are specialized defense compounds in Apiaceae, but the evolutionary path of their biosynthesis is not well understood. We generated a telomere-to-telomere (T2T) genome for Sanicula chinensis, an early-diverging species within the Saniculoideae subfamily, to explore its evolution. Comparative genomics revealed that S. chinensis and Apioideae species each underwent unique whole-genome duplication (WGD). Unlike most species in the Apioideae subfamily, S. chinensis produces a limited diversity and content of furanocoumarins but shows high esculetin levels. This metabolic profile likely stems from three genetic factors: elevated expression of p-Coumaroyl ester 3'-hydroxylase (C3'H) and hydroxycinnamoyl-CoA shikimate/quinate hydroxycinnamoyl transferase (HCT), which shift the metabolic pathway toward simple coumarins; the absence of a key biosynthetic gene cluster, including prenyltransferase (PT) and p-coumaroyl-CoA 2'-hydroxylase (C2'H), found in Apioideae; and incomplete or inactive PT enzymes in S. chinensis. Our results not only shed light on the evolutionary history of furanocoumarin biosynthesis in Apiaceae, but also provide avenues for tailoring furanocoumarin content for agricultural or medical applications in plants.

Furocoumarins↗

Molecular cloning of Echis ocellatus disintegrins reveals non-venom-secreted proteins and a pathway for the evolution of ocellatusin.

We report the cloning and sequence analysis of Echis ocellatus cDNAs coding for dimeric disintegrin subunits and for the short disintegrin ocellatusin. All the dimeric disintegrin subunit messengers belong to the short-coding class, indicating that short messengers may be more widely distributed than previously thought. Mass spectrometric analysis of the HPLC-separated venom proteins was performed to characterize the dimeric disintegrins expressed in the venom proteome. In addition to previously reported EO4 and EO5 heterodimers, a novel dimeric disintegrin containing RGD- and KGD-bearing subunits was identified. However, a WGD-containing polypeptide encoded by clone Eo1-1 was not detected in the venom, suggesting the occurrence of larger genomic than proteomic diversity, which could represent part of a non-venom-secreted reservoir of disintegrin that may eventually acquire physiological relevance for the snake upon changes of ecological niches and prey habits. On the other hand, the realization of the existence of two distinct messengers coding for the short disintegrin ocellatusin reveals key events of the evolutionary emergence of the short disintegrin ocellatusin from a short-coding dimeric disintegrin precursor by two nucleotide mutations.

Amino Acid Sequence↗

Impaired leptin A signaling disrupts hepatic lipid metabolism and growth in female medaka (Oryzias latipes).

Leptin is a central regulator of appetite and energy metabolism in vertebrates, and its deficiency in mammals typically results in hyperphagia and severe obesity. In fish, however, the physiological roles of leptin remain less clearly defined, partly due to the whole genome duplication (WGD) and divergent expression patterns. In this study, we generated a leptin A (lepa) loss-of-function mutant in medaka (Oryzias latipes) using CRISPR/Cas9 to investigate the function of leptin signaling. Phenotypic analysis revealed that female homozygous mutants exhibited significantly reduced body length and body weight compared with wild-type females, indicating growth impairment. Unexpectedly, despite their lean phenotype, the female mutants developed pronounced hepatic steatosis accompanied by the formation of spongiosis hepatis structures, while no obvious fibrosis was detected. To explore the molecular mechanisms underlying these abnormalities, transcriptomic profiling of mutant livers was performed. Differentially expressed genes were significantly enriched in pathways related to lipid metabolism, including Fatty acid metabolism and PPAR signaling pathway, suggesting a potential reduction in hepatic fatty acid β-oxidation capacity. In addition, genes involved in endoplasmic reticulum stress, autophagy, and apoptosis were altered, indicating transcriptional changes in cellular stress-response pathways under leptin A deficiency. Together, these findings suggest that leptin A may play an important role in coordinating growth and hepatic lipid metabolism in medaka and highlight potential differences in leptin-mediated metabolic regulation between fish and mammals.

Animals↗

Primulina pan-genome reveals differential gene retention following whole-genome duplications and provides insights into edaphic specialization.

Primulina, a genus of >200 species specialized to extreme soils, provides a model for edaphic adaptation. We assemble seven genomes and construct a pan-genome spanning nine species from karst, Danxia, and acidic soils. Comparative analyses reveal that karst-adapted species have smaller genomes. Two lineage-specific whole-genome duplications (WGDs) exhibit biased duplicate loss in large gene families but preferential retention of transcription factors, indicating combined adaptive and nonadaptive forces. Pan-genome analyses identify ion channel and transporter genes enriched in variant hotspots and under positive selection in karst lineages. Candidate genes for drought and salt stress tolerance include ABC transporters and ion channels. Notably, an ABC transporter shows positive selection in karst species and unique structural variation in non-karst species. Together, our findings show that genome downsizing, biased post-WGD retention, and evolution of ion-transport pathways shape adaptation to extreme soils. The Primulina pan-genome provides a resource for dissecting mechanisms underlying edaphic specialization.

Gene Duplication↗

Algae-to-host horizontal gene transfer in Paramecium bursaria is associated with host adaptation during endosymbiosis.

Paramecium bursaria maintains a stable endosymbiosis with green algae, yet the evolutionary consequences of this association remain unclear. Here, we screened the host genome for algal-derived horizontally transferred genes (HTGs) using a lineage-aware workflow designed to detect horizontal gene transfer (HGT) between two defined lineages. We identified 16 candidate HTGs, including four putative newly transferred genes and 12 homologous transferred genes, most of which were functionally associated with redox homeostasis and metabolism. Five HTGs showed symbiosis-dependent expression. RNAi knockdown of GH32s and SATs reduced host proliferation, total cell area, and motility, while GH32s knockdown also reduced endosymbiont load. Duplication patterns suggest that most transfers may have occurred after the P. bursaria lineage diverged from the sampled Paramecium species but before its lineage-specific whole-genome duplication (WGD). The HTGs also showed host-associated shifts in GC content and gene length, while representative HTGs retained conserved domains and functional motifs. Together, our results support algae-to-host HGT in P. bursaria and suggest that some transferred genes may contribute to metabolic integration during endosymbiosis.

Gene Transfer, Horizontal↗

Biosynthesis and heterologous production of the α-agarofuran scaffold of Celangulin V from Celastrus angulatus.

Celangulin V is a widely used biopesticide derived from Celastrus angulatus, and features antifeedant and insecticidal properties as a dihydro-β-agarofuran (DHβAF) sesquiterpenoid. Its biosynthesis remains largely unexplored. Here, we assemble a chromosome-level and haplotype-resolved reference genome of C. angulatus, with each haplotype assembled into 23 pseudochromosomes and achieving scaffold N50 of 14.31 and 14.01 Mb, respectively. This high-quality genome reveals that a recent β whole-genome triplication (β-WGT) event occurred ~34.3 million years ago, and that the expansion of sesquiterpene synthases and cytochrome P450s from the CYP71BE family results from whole-genome duplication (WGD) event and tandem duplication, respectively. We identify CaTPS16 as a γ-eudesmol synthase, and show that CYP71BE416 further catalyzes the γ-eudesmol to tetrahydrofuran ring α-agarofuran for Celangulin V biosynthesis. We further achieve the de novo synthesis of α-agarofuran in Saccharomyces cerevisiae through combined coexpression of these genes. This study has significantly increases the available genomic resources of the Celastraceae family, improves our understanding of the biosynthetic origins and evolution of the tetrahydrofuran ring in DHβAF sesquiterpenoids, and enables its heterologous bioproduction in microbial chassis.

Celastrus↗

Bistable Mutation-Selection Equilibria and Violations of Fisher's Theorem in Tetraploids: Insights from Nonlinear Dynamics.

Polyploidy and whole genome duplication (WGD) are widespread biological phenomena with substantial cellular, meiotic, and genetic effects. Despite their prevalence and significance across the tree of life, population genetics theory for polyploids is not well developed. The lack of theoretical models limits our understanding of polyploid evolution and restricts our ability to harness polyploidy for crop improvement amidst increasing environmental stress. To address this gap, we developed and analyzed deterministic models of mutation-selection balance for tetraploids under polysomic (autotetraploid) and disomic (allotetraploid) inheritance patterns and arbitrary dominance relationships. We also introduced a new mathematical framework based on ordinary differential equations and nonlinear dynamics for analyzing the models. We find that autotetraploids approach Hardy-Weinberg Equilibrium 33% faster than allotetraploids, but the different tetraploid inheritance models show little differences in mutation load and allele frequency at mutation-selection balance. Our model also reveals two bistable points of mutation-selection balance for dominant alleles with biased mutation rates over a wide range of selection coefficients in the tetraploid models compared to bistability in only a narrow range for diploids. Finally, using discrete time simulations, we explore the temporal dynamics of allele frequency and fitness change and compare these dynamics to the predictions of Fisher's Fundamental Theorem of Natural Selection. While Fisher's predictions generally hold, we show that the bistable dynamics for dominant mutations fundamentally alter the associated temporal dynamics. Overall, this work develops foundational theoretical models that will facilitate the development of population genetic models and methodologies to study evolution in empirical tetraploid populations.

Fisher’s Fundamental Theorem↗

Comprehensive identification and analysis of clusters of tandemly duplicated genes reveal their contributions to adaptive evolution of green plants.

Tandem gene duplication occurred more frequently compared with the episodic whole-genome duplication (WGD), providing a continuous supply of genetic material for evolutionary innovation and adaptation to changing environments. The rising roles of clusters of tandemly duplicated genes (CTDGs) in the evolution of phenotypic diversity have been unraveled in mammals. However, the content and biological roles of CTDGs remain largely unknown in plants. Here, we comprehensively identified CTDGs in 220 published plant genomes representing major lineages of green plants. The number of CTDGs showed great variation across taxa, ranging from 0 to 6028. The size of CTDGs varied from 2 to 47 genes, with small clusters containing two members predominating. Interestingly, significant expansion of CTDGs was found in early-diverging land plants and is closely associated with the evolution of key traits (e.g., ABA response, plant cuticle, UV-B resistance) required for plants to conquer terrestrial environments. Functional enrichment analysis revealed conserved and specialized functional profiles among different sizes of CTDGs in both Arabidopsis thaliana and the bryophyte Physcomitrium patens. Small CTDGs were enriched in fundamental stress responses, including protein modification, signal transduction, and responses to diverse stress stimuli, while large CTDGs were enriched in more sophisticated processes such as plant hormone biosynthesis and signaling, plant-microbe interactions, and reproductive processes. Expression pattern analyses of CTDGs under different stress conditions in A. thaliana and P. patens revealed that the highest number of CTDGs showed differential expression under drought stress, suggesting important roles of CTDGs in the evolution of desiccation tolerance in early land plants. The results of this study provide new additions to our knowledge about the abundance of CTDGs across green plants and reveal their important contributions to enable plants to overcome stressful environments on land.

Gene Duplication↗

Genome sequencing and population genetics provide insights into local adaptation of Opisthopappus species on cliff environments of Taihang Mountains.

Local adaptation represents a pivotal theme in evolutionary biology. The Opisthopappus genus, comprising Opisthopappus longilobus and O. taihangensis, thrives on the cliffs of the Taihang Mountains. During their evolutionary history, two species are hypothesized to have locally adapted to their cliff habitats. In the present study, we employed a combined approach of whole-genome sequencing of O. taihangensis and population genomic analysis from both species to gain deeper insights into their patterns of local adaptation. Our results revealed that the expansive genome of O. taihangensis (3010.18 Mb), a consequence of a whole-genome duplication (WGD) event, coupled with a high proportion of repetitive sequences (82.70%), was postulated as one of its adaptive strategies. A clear differentiation between O. taihangensis and O. longilobus was observed, with the two species diverging approximately 17.57 million years ago (Mya), with O. longilobus serving as the ancestor. Since their divergence, limited gene flow was observed between the two species. Post-divergence, the effective population sizes of both species expanded, yet underwent a dramatic reduction at approximately 0.07 Mya. Furthermore, a total of 798 adaptive genes were identified, of which 207 overlapped with expanded genes, and eight genes were found to be under positive selection. These genes primarily regulated the growth and development of both species via pathways such as oxidation-reduction and ubiquitin-proteasome, enabling them to withstand climate changes. These findings provide profound insights into the local adaptation of Opisthopappus species to the cliff environments and offer valuable clues for further exploring the local adaptation among various cliff-dwelling organisms.

Adaptation, Physiological↗

Interaction between the insulin-like growth factor family and the integrin receptor family in tissue repair processes. Evidence in a rabbit ear dermal ulcer model.

We have determined previously that IGF-I is dependent on the presence of IGF binding protein-1 (IGFBP-1) to act as a wound healing agent. We sought to determine the mechanism whereby IGFBP-1 is able to enhance IGF-I bioactivity. As IGFBP-1 binds both the alpha5beta1 integrin as well as IGF-I in vitro, we asked which of the following interactions were important: (a) the ability of IGFBP-1 to interact with an integrin receptor, and/or (b) the binding of IGF-I by IGFBP-1. We used an IGF-1 analogue (des(1-3)IGF-I) with a > 100-fold reduction in affinity for IGFBP-1 as well as an IGFBP-1 mutant (WGD-IGFBP-1) which does not associate with the alpha5beta1 integrin to selectively abrogate each of these interactions. We also tested the ability of IGFBP-2, a related binding protein which has an arginine-glycine-aspartate sequence but does not associate with integrin family members, to enhance IGF-I bioactivity. Full-thickness dermal wounds were created on rabbit ears; various combinations of native IGF-I, native IGFBP-1, native IGFBP-2, and their respective analogues/mutants were applied to each wound. Wounds were harvested 7 d later for analysis. Only native IGF-I in combination with native IGFBP-1 was effective as a wound healing agent, enhancing reepithelialization and granulation tissue deposition by 64+/-5 and 83+/-12% over controls (P = 0.008 and 0.016, respectively). The same doses of IGF-I/WGD-IGFBP-1, des(1-3)IGF-I/IGFBP-1, and IGF-I/IGFBP-2 were ineffective. We propose that IGF-I physically interacts with IGFBP-1 and that IGFBP-1 also binds to an integrin receptor, most likely the alpha5beta1 integrin. This interaction is unique to IGFBP-1 as the closely related IGFBP-2 had no effect, a finding consistent with its inability to bind to integrin receptors. Our results suggest that activation of both the IGF-I receptor and the alpha5beta1 integrin is required for IGF-I to stimulate wound healing.

Animals↗

PAHG: the database of human multi-gene families.

BACKGROUND: In the early vertebrate history, gene duplications, including single-gene, segmental-gene (SSD), and whole-genome duplication (WGD), formed multigene families. Despite efforts to classify metazoan multigene families hierarchically for evolutionary insight, a gap exists in accessible, curated resources for human/vertebrate multigene families. RESULTS: Addressing this, we present the Phylogenomic Analysis of Human Genome (PAHG) database. It focuses on curated multigene families in the human genome, particularly within four paralogons: HOX-bearing (Hsa:2/7/12/17), FGFR-bearing (Hsa:4/5/8/10), MHC-bearing (Hsa:1/6/9/19), and chromosomes 1/2/8/20. CONCLUSION: The current PAHG version details the phylogenetic history of 221 human multigene families (1247 gene members) with 15,231 protein sequences from diverse metazoans. It provides insights into gene duplication timings, co-duplication events, and their relationships with human genome syntenic organization. The PAHG database addresses the lack of accessible resources, offering valuable information on human/vertebrate multigene family evolution. Access the PAHG database at: https://www.pahgncb.com/ and http://pahg.qau.edu.pk/ . This resource enriches our understanding of vertebrate genetic evolution.

Humans↗

Insulin-like growth factor (IGF)-binding proteins inhibit the smooth muscle cell migration responses to IGF-I and IGF-II.

Smooth muscle cells have been shown to migrate in response to insulin-like growth factor I (IGF-I). However, the role of IGF-binding proteins (IGFBPs) in this process has not been determined. As IGFBPs are synthesized and secreted by smooth muscle cells and bind to IGFs with high affinity, this study was undertaken to determine the ability of IGFBP-1 and -2 to modulate cellular migration in response to IGF-I and -II. Confluent monolayers of porcine vascular smooth muscle cells were wounded with a razor blade. After wounding, IGF-I and -II induced increases of 159 +/- 49% (mean +/- SD) and 108 +/- 33%, respectively, above control values in the number of cells migrating over a fixed distance in 4 days. The addition of IGFBP-1 caused a 19-21% inhibition of IGF-I- or IGF-II-stimulated migration, whereas the addition of IGFBP-2 inhibited the effect of both by greater than 60%. The addition of IGFBP-2 alone had no effect, whereas IGFBP-1 addition was associated with a 42 +/- 12% increase. In contrast, [Trp221]IGFBP-1 in which the RGD sequence was changed to WGD, thus eliminating its capacity to bind to the alpha 5 beta 1 integrin, inhibited IGF-I-stimulated migration by 67 +/- 17%. An IGF analog that has a reduced affinity for IGFBP-2-stimulated migration equally well as IGF-I alone even in the presence of IGFBP-2. Likewise, the addition of insulin, which cannot bind to IGFBPs, at supraphysiological concentrations that are adequate to activate the IGF-I receptor resulted in a similar increase in migration. In summary, IGF-I and -II stimulate smooth muscle cell migration after wounding. This migratory response is modulated by IGFBPs. Both IGFBP-1 and IGFBP-2 appear to neutralize the effects of the IGFs by inhibiting their interaction with IGF receptors, but IGFBP-1 also has a direct stimulatory effect that requires an intact RGD integrin recognition sequence.

Animals↗

Insulin-like growth factor-binding protein 1 stimulates human trophoblast migration by signaling through alpha 5 beta 1 integrin via mitogen-activated protein Kinase pathway.

A highly migratory subpopulation of the human placental trophoblast, known as the extravillous trophoblast (EVT), invades the uterus and its vasculature, to establish adequate exchange of key molecules between the maternal and fetal circulations. During their formation, EVT cells selectively acquire alpha 5 beta 1 integrin. We had shown that alpha 5 beta 1 is required for their migratory function, and that EVT cell migration is stimulated by insulin-like growth factor-binding protein (IGFBP)-1 produced by the uterine decidua. The present study examined whether this stimulation is dependent on binding of the Arg-Gly-Asp (RGD) domain of IGFBP-1 to an RGD binding site on the alpha 5 beta 1 integrin, followed by activation of focal adhesion kinase (FAK) and stimulation of the mitogen-activated protein kinase (MAPK) pathway. IGFBP-1 treatment increased migration of EVT cells, whereas an anti-alpha 5 beta 1 integrin antibody blocked migration regardless of IGFBP-1 treatment. Migration stimulation by IGFBP-1 was abrogated by pretreatment with a Gly-Arg-Gly-Asp-Ser-Pro (GRGDSP), but not a Gly-Arg-Gly-Glu-Ser-Pro (GRGESP) hexapeptide, and by mutation of the RGD domain of IGFBP-1 to Trp-Gly-Asp (WGD). IGFBP-1 treatment caused a rapid localization of immunoreactive FAK to cellular lamellipodia, a rapid increase in phosphorylation of FAK and extracellular-signal regulated kinases 1 and 2. Preincubation of EVT cells with Herbimycin A, a tyrosine kinase inhibitor, abrogated IGFBP-1 effects; whereas an MAPK kinase inhibitor, PD 98059, reduced migration regardless of IGFBP-1 treatment. These results indicate that IGFBP-1 stimulation of EVT cell migration occurs by binding of its RGD domain to the alpha 5 beta 1 integrin, leading to activation of FAK and stimulation of MAPK pathway.

Animals↗

Genus-Wide Pan-Genome Analysis of Populus bZIP Transcription Factors with Reanalysis of Public Salt-Stress Transcriptomes.

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.

Populus↗

Ancient polyploidization waves as evolutionary shields for angiosperms.

Chen et al. identified 132 whole-genome duplications (WGDs) clustered around environmental crises. We highlight how, over longer evolutionary timescales, ancient WGDs convergently retained MADS-box, MYB, WRKY and HSF transcription factors, building stress-adaptation networks. These insights guide climate-resilient crop improvement through comparative genomics and CRISPR engineering.

MADS-box↗