Plant Reproduction

Parthenogenesis of totipotent egg cells is rare, yet widespread, across the tree of life but mechanistic insights into factors that control parthenogenesis remain sparse. The Taraxacum officinale PARTHENOGENESIS (ToPAR) gene encodes a C2H2-zinc finger and EAR domain containing protein which is required for parthenogenesis and clonal seed production in apomictic dandelions. Ectopic expression of ToPAR can trigger egg cell division in lettuce and maternal haploid induction in foxtail millet, and ToPAR has been employed in a high-penetrance synthetic apomixis system in hybrid rice. To date a convenient model system to study ToPAR function has yet to be established nor has the capacity for ToPAR to trigger cell division in non-gametic cells been tested. Here, we demonstrate that expression of ToPAR in egg cells of Arabidopsis thaliana using the EGG-CELL 1.1 promoter (pAtEC1.1) causes a reduction in seed set and can trigger egg cell division without fertilization. We found that the pAtEC1.1:ToPAR transgene is rarely transmitted through the female lineage where it causes aberrant cell divisions. Expression of ToPAR in sexual embryos under the WUSCHEL RELATED HOMEOBOX 8 (AtWOX8) promoter alters cell patterning disrupting morphogenesis. Our results demonstrate that A. thaliana can be a powerful system to dissect the mode of action of ToPAR, and that gamete-specific co-factors are not essential for its function.

Arabidopsis Leucine-Rich Repeat-Malectin Receptor Kinase (LRR-MAL RK) genes have been previously implicated in the early stages of pollen-pistil interactions to support compatible pollen. One member, Receptor Kinase in Flowers 1 (RKF1), has been associated with roles in the stigma to support pollen hydration as well as pollen tube growth. To better understand the function of RKF1 in these processes, a yeast two-hybrid screen was conducted with the RKF1 cytosolic kinase domain. Two positive interactors identified from this screen were the Group VII Ethylene Response Factors (ERFVIIs), RELATED TO APETALA 2.12 (RAP2.12) and RAP2.3. Their putative roles in pollen-pistil interactions were investigated using the quintuple erfvii mutant, and novel pistil-mediated pollen tube callose deposition phenotypes were uncovered during the pollen tube growth stage. Loss of seven LRR-MAL RKs including RKF1 in the pistil was previously found to cause an unusual phenotype where shorter callose plugs were deposited in wildtype pollen tubes compared to that seen in wildtype Col-0 pistils. Contrary to this, wildtype pollen tubes growing through the quintuple erfvii mutant pistil deposited callose plugs that were more elongated than that seen in wildtype Col-0 pistils. Further analyses with the proteolysis 6 (prt6) mutant and RAP2.12 rescue constructs were consistent with these phenotypes providing support that RKF1 is a negative regulator of RAP2.12 and RAP2.3 in the pistil during pollen tube growth.

The rejection of self-incompatible (SI) Brassica pollen is mediated by three signaling branches that function in parallel in the stigma. The recognition of SI pollen by the stigma S-Receptor Kinase (SRK) results in activation of the ARM-Repeat-Containing 1 E3 ubiquitin ligase (ARC1) which mediates the degradation of compatibility factors, the FERONIA (FER) and ANJEA (ANJ) receptor kinases that induces ROS accumulation to inhibitory levels and the M Locus Protein Kinase (MLPK) which may also be connected to ROS production. Arabidopsis self-incompatibility is regulated by SRK as well, but the signaling events downstream of SRK following SI pollen perception are less well-understood. In this study, we evaluated the requirements of FER, ANJ and HERCULES RECEPTOR KINASE 1 (HERK1) for SI pollen rejection in the transgenic Arabidopsis thaliana SI-Col-0{psi} srka-1 line. The{psi} srka-1 T-DNA disrupting the expression of the endogenous{psi} SRKA gene was crossed into SI-Col-0 to prevent any potential SRK transgene silencing. T-DNA mutants for FER and ANJ/HERK1 were then crossed into the SI-Col-0{psi} srka-1 line. Using standard assays for pollen-stigma interactions, the SI phenotypes were assessed for the SI-Col-0 fer, SI-Col-0 anj-1 and SI-Col-0 anj-1 herk1-1 lines. Our results presented here indicated that FER and ANJ are not required in the stigma for Arabidopsis SI pollen rejection, further providing evidence for a divergence in the SI downstream signaling pathway in Arabidopsis.

Flower opening is a complex developmental process involving coordinated changes in cell proliferation and cell expansion. Although several regulators of flower opening have been identified, how transcriptional programs are coordinated with the cellular and metabolic changes underlying petal expansion immediately before flower opening remains incompletely understood. Japanese morning glory (Ipomoea nil) is a suitable model for investigating these processes because its flowers open synchronously at a predictable time. This study aimed to identify transcriptional regulators involved in petal development and flower opening in Japanese morning glory. Temporal analyses of petal growth, sugar metabolism, and gene expression revealed that petal development was driven by both cell proliferation and cell expansion until approximately 48 h before flower opening, whereas cell expansion predominated thereafter. Weighted gene co-expression network analysis identified two genes encoding R2R3-MYB subgroup 19 transcription factors, InMYB21A and InMYB21B, as candidate regulators associated with petal development. CRISPR/Cas9-mediated knockout analysis revealed a prominent role for InMYB21B, whose loss markedly impaired petal cell expansion and prevented flower opening. InMYB21B knockout also impaired stamen and pistil development, resulting in male and female sterility. Starch degradation and glucose accumulation were impaired in InMYB21B knockout petals. Transcriptome analysis revealed delayed transcriptomic progression during petal development and reduced expression of genes associated with starch degradation, sucrose metabolism, cell wall remodeling, and water transport. These findings identify InMYB21B as a key regulator of petal cell expansion and flower opening in Japanese morning glory and show that loss of InMYB21B disrupts both metabolic and transcriptomic progression during late petal development.

In angiosperms, ovule development requires the activity of the C, D and E classes of MADS genes, which encode key transcriptional regulators of reproductive development. The SEPALLATA (SEP) MADS transcription factors (MTFs), which belong to the E class, act as organizing hubs of MADS heterotetrameric complexes and play an essential role in the development of flower organs. However, the role of the SEP genes in ovule and seed development has been difficult to determine due to redundancy in the subclade, the lack of observable phenotypes in single and double sep1 sep2 mutants and the homeotic conversion of the carpel into sepal or leaf in higher order sep mutants. Here, we engineered a version of SEP3 (SEP3{Delta}M) that encodes a protein lacking the DNA-binding MADS-domain but retains the oligomerization domains needed for MADS protein heterotetramerization. In vitro experiments demonstrated the ability of SEP3{Delta}M to interact with the C and D classes of MTF, reducing the capability of such MADS complex to efficiently bind DNA. sep3{Delta}M plants showed a delay in flower opening and organ maturation and a reduced fertility. The ovules exhibited reduced outer integument growth, and the few seeds that developed showed impaired mucilage secretion upon imbibition. RNA-seq analysis of sep3{Delta}M demonstrated misregulation of genes involved in outer integument and seed coat development. Taken together, these data indicate the key role of SEP3-containing MADS complexes in proper ovule outer integument growth and seed coat development.

Potato is an important non-cereal food crop worldwide. However, the limited number of functionally validated genes remains a major bottleneck to favorable allele stacking and genome design breeding in potato. Rapid advances in AI agents offer a promising means to support crop breeding by translating natural-language questions into coordinated data analysis and knowledge retrieval. Their reliable use for potato breeding, however, is constrained by fragmented multi-omics resources that lack consistent curation and machine-accessible interfaces. Here, we constructed an agent-ready potato multi-omics database integrating genomic resources from 150 potato accessions, 259 bulk RNA-seq samples, and 14 spatial transcriptomic datasets into a pangenome, a tissue expression atlas, co-expression networks, and spatial expression maps accessible through open APIs. We developed 39 potato-specific Agent Skills for reproducible bioinformatics analysis and comprehensive data and knowledge exploration, enabling natural-language questions to be translated into standardized data-retrieval and analysis tasks. By integrating direct evidence from potato studies, functions of homologous genes in Arabidopsis, rice, and maize, and tissue expression patterns, we generated genome-wide functional predictions for 37,658 genes in the DM reference genome. We further developed Potato Agent as a multi-user, browser-based platform with isolated workspaces and online result preview, reducing the technical burden of agent deployment and providing direct access to integrated data, knowledge, and workflows. Case studies demonstrated its capabilities in reproducible bioinformatics analysis, agent-assisted identification of a tuber development regulator, scientific data visualization, and haplotype-aware promoter analysis and sgRNA design. Together, the agent-ready database and Potato Agent provide an integrated infrastructure for functional gene discovery and hybrid breeding in potato.

Mechanistic models of plant regulatory networks typically require extensive parameterization, limiting their generalisation and scalability. Here we present a parameter-free, topology-driven model of shoot branching that predicts phenotypic outcomes from network structure alone. We constructed a signed, directed causal network by distilling regulatory relationships from the published literature spanning many laboratories, species, years, data types, and methodological frameworks. This extracted the essential logic of the system, consistent with developmental-biological reasoning and anchored in empirical evidence. Using PSoup, which automatically translates network topology into algebraic equations, the model propagates information across the network and predicts the qualitative direction of change relative to a defined baseline, mirroring the comparative framework of biological experiments. The pipeline, from network construction through automated equation generation to prediction, is transparent and reproducible. Trained against branching phenotype data with 78 diverse perturbations spanning genetic mutations and hormone treatments, the model achieved 86% accuracy in predicting branching direction. On an independent test set of 84 perturbations measuring bud release and gene expression at nodes not used during training, accuracy reached 75%. The approach highlighted deficiencies in our understanding of the topology of the network around SMXL 6/7/8 and ABA nodes. Other errors came mainly from modelling choices, such as the threshold for scoring a node as changed relative to baseline. Beyond shoot branching, this work demonstrates a general strategy for synthesizing biological knowledge into validated predictive networks, providing a foundation for both applied breeding and the advancement of fundamental biology.

Utricularia gibba L. is an aquatic carnivorous plant with a diverse set of capabilities. Reddening of traps frequently occurs in old in vitro cultures. While anthocyanins are often responsible for red coloration in plants, not every plant turns red. Stress factors like high light or excess sucrose have previously been shown to induce the formation of anthocyanins. Here, we hypothesized the red trap formation to be dependent on nutrient deprivation and tested nitrogen deprivation. The results suggest, that only in combination with light, nitrogen deficiency leads to the activation of the complete anthocyanin biosynthesis pathway and visible red coloration. However, in darkness, anthocyanin biosynthesis appears generally less active compared to light conditions and expression of most anthocyanin biosynthesis genes is not significantly upregulated under nitrogen deficiency.

Stomata are the pores on plant surface, and these tiny pores are responsible for the flow of gas between plants and atmosphere. Currently, what effects of the broad and continuous increase in stomatal density achieved via genetic engineering on plant growth and development remain poorly understood. The 9 Arabidopsis transgenic lines with increased stomatal density were acquired through overexpressing FSTOMAGEN (the homologs of STOMAGEN, which are in Flaveria). The intermediate stomatal density (SD) lines exhibited increased trend in biomass. Compared with the lines with low SD, the biomass of Arabidopsis lines with intermediate SD (484 mm-2) significantly increased. There was a positive and significant correlation between biomass and relative water content. Across these transgenic lines, only during the earlier phase of growth, the leaf area exhibited a gradually increased trend as stomatal density increased, and there was both a significant linear relationship between SD and leaf growth rate and a strong linear relationship between SD and leaf area. In contrast, a clear relationship during the later phase wasnt observed. Under lower growth light intensity, there was an increased trend of biomass from other lines to the lines with intermediate SD, and the photosynthetic rate and stomatal conductance of the intermediate line were significantly increased. This study reveals plant-growth alterations that correspond to broad and near-continuous increases in stomatal density achieved via genetic engineering. Our study sheds light on the prerequisites for elevated stomatal density achieved via genetic engineering to promote plant growth.

Although the biosynthetic pathways of benzylisoquinoline alkaloids (BIAs) have been extensively investigated in several plant species, their transcriptional regulatory mechanisms remain only partially understood. Jasmonate (JA)-responsive group IX APETALA2/Ethylene Responsive Factor (AP2/ERF) transcription factors (TFs) are well-known regulators of specialized plant metabolism, including the biosynthesis of various alkaloids. However, their specific roles in BIA biosynthesis remain largely elusive. Here, we isolated five novel group IX AP2/ERF TFs, designated Benzylisoquinoline alkaloid Jasmonate-responsive AP2/ERF (BJE1-5), from Coptis japonica. Phylogenetic analysis revealed that Benzylisoquinoline alkaloid Jasmonate-responsive AP2/ERF (BJE) proteins belong to subclades distinct from group IXa, which contains well-known AP2/ERF TFs involved in alkaloid biosynthesis. Transient expression analyses in C. japonica protoplasts demonstrated that certain BJEs, particularly CjBJE3 and CjBJE5, positively regulated BIA biosynthetic genes through a mutual regulatory network among BJE members. Moreover, CjBJE3 expression was regulated by CjbHLH1, a unique-type basic helix-loop-helix (bHLH) TF specific to BIA-producing plants. Furthermore, heterologous expression of CjBJE3 and CjBJE5 in cultured Eschscholzia californica cells significantly enhanced the overall BIA production, particularly by increasing end-product benzophenanthridine BIAs, highlighting several uncharacterized biosynthetic genes clustered in the genome. Our findings suggest that BIA-producing species have developed a specific regulatory network comprised of CjbHLH1 and BJE TFs, providing valuable clues for identifying novel biosynthetic enzymes.

Soybean, a widely cultivated leguminous crop valued for its protein, amino acids, and oil, faces the challenge of maintaining protein levels, which have an inverse correlation with yield. Reducing leaf chlorophyll levels could increase seed protein levels without compromising yield; however, this is yet to be tested. Therefore, to understand the impacts of low chlorophyll mutations on soybean yield and seed composition, we screened and compared 25 low chlorophyll soybean mutants to their 11 dark green parents. PI548210 (Lincoln mutant) demonstrates a higher concentration of protein without affecting yield compared to its dark green parent PI548362 (Lincoln), suggesting it as a good candidate for further large-scale field trials. PI547555 (Y11/y11, Clark mutant) demonstrates a lower concentration of oil without impacting yield, alongside lower gross photosynthesis, but with chlorophyll levels in the pod and seed tissues that are comparable to its dark green parent PI548533 (Clark). These findings are consistent with the oil concentration of the soybean being influenced by pod and seed photosynthesis, which is correlated with pod height and row spacing. Chlorophyll levels in the leaf do not necessarily correlate with those in the pod and seed of low chlorophyll mutants, possibly due to substantially lower expression of chlorophyll synthesis genes in the pod and seed. SIGNIFICANCEO_LIPI548210 (Lincoln mutant), one of twenty-five low chlorophyll soybean mutants, demonstrates a higher concentration of soybean protein without affecting yield compared to its dark green parent (Figure 1 and Table 1). C_LIO_LIPI547555 (Y11/y11, Clark mutant), a low chlorophyll soybean mutant, demonstrates a reduced concentration of soybean oil without impacting yield, alongside lower gross photosynthesis in pod and seed tissues compared to its dark green parent (Figures 3 and Table 2). These findings suggest that the oil concentration of the soybean is influenced by pod and seed photosynthesis, which is in turn influenced by pod height and row spacing (Figure 2). C_LIO_LIChlorophyll levels in the leaf do not necessarily correlate with those in the pod and seed of low chlorophyll mutants, possibly due to substantially lower expression of chlorophyll synthesis genes in the pod and seed (Figure 5-6). C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=84 SRC="FIGDIR/small/744892v1_fig1.gif" ALT="Figure 1"> View larger version (55K): org.highwire.dtl.DTLVardef@4282dcorg.highwire.dtl.DTLVardef@9d565forg.highwire.dtl.DTLVardef@1918292org.highwire.dtl.DTLVardef@1359b1_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 1.C_FLOATNO Two low chlorophyll mutants are as healthy as their dark green parents. Lincoln and its low chlorophyll mutant, left; Clark and its low chlorophyll mutant, known as Y11/y11, right. It can be seen by eye that the plants have low chlorophyll (light green/yellow leaves) but a similar growth habit to their dark green parents. See Supplemental Figures 1-4 for contrast, where low chlorophyll mutants are stunted in growth compared to their dark green parents. C_FIG O_TBL View this table: org.highwire.dtl.DTLVardef@657ec9org.highwire.dtl.DTLVardef@166e75borg.highwire.dtl.DTLVardef@df23c7org.highwire.dtl.DTLVardef@1a60124org.highwire.dtl.DTLVardef@194ed96_HPS_FORMAT_FIGEXP M_TBL O_FLOATNOTable 1.C_FLOATNO O_TABLECAPTIONComparison of seed yield, weight, seed composition between low chlorophyll mutants and their dark green parents. ANOVA is used with linear mixed model (random effect = block, fixed effect = variety). Least squares mean is used to compare. For yield and seed composition, N=4 blocks. For leaf chlorophyll (SPAD), N=40. Yield is average yield per plant (g). n.s. = not significant. C_TABLECAPTION C_TBL O_FIG O_LINKSMALLFIG WIDTH=179 HEIGHT=200 SRC="FIGDIR/small/744892v1_fig3.gif" ALT="Figure 3"> View larger version (26K): org.highwire.dtl.DTLVardef@7a368aorg.highwire.dtl.DTLVardef@192b8f0org.highwire.dtl.DTLVardef@1abb738org.highwire.dtl.DTLVardef@89e978_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 3.C_FLOATNO Light response curve of low chlorophyll mutant (Y11/y11, PI547555) and its parent (Clark, PI548533). Rates of net and gross photosynthesis of low chlorophyll (white) and dark green parents (black) pods under field conditions. Each dot represents a value (n=4) {+/-}SE. We assumed that the seeds greatly inhibited the transmittance of light through the pod and used photosynthetic photon flux density for a single-side. C_FIG O_TBL View this table: org.highwire.dtl.DTLVardef@3f0528org.highwire.dtl.DTLVardef@16ba712org.highwire.dtl.DTLVardef@a5ab2aorg.highwire.dtl.DTLVardef@889254org.highwire.dtl.DTLVardef@3efa4f_HPS_FORMAT_FIGEXP M_TBL O_FLOATNOTable 2.C_FLOATNO O_TABLECAPTIONPod photosynthetic parameters for low chlorophyll mutant (Y11/y11, PI547555) and its parent (Clark, PI548533). Photosynthesis was measured 1 September through 15 September 2021 at the University of Illinois Energy Farm in Urbana, IL, USA. The statistical analysis was done using ANOVA with linear mixed model (alpha=0.05). N=4 {+/-} SEM for Clark and N=3 {+/-} SEM for Y11. C_TABLECAPTION C_TBL O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=130 SRC="FIGDIR/small/744892v1_fig2.gif" ALT="Figure 2"> View larger version (23K): org.highwire.dtl.DTLVardef@a36c26org.highwire.dtl.DTLVardef@1116c8forg.highwire.dtl.DTLVardef@ee5e61org.highwire.dtl.DTLVardef@1766712_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 2.C_FLOATNO Low chlorophyll mutant (Y11/y11, PI547555) and its parent (Clark, PI548533) differ in concentration of seed oil, which interacts with height of pod and row spacing. The box plots show the median (central line), the lower and upper quartiles (box) and the minimum and maximum values (whiskers). The statistical analysis was done using ANOVA with linear mixed model (n=3 blocks, alpha=0.05). Least squares mean is used to compare. N.s., non- significant in the analysis. A. Concentration of oil in low chlorophyll mutant seeds from the upper canopy decreased by 4% compared to the dark green parent (18.2% vs 19%) while there was no difference between them in the seeds from the lower canopy (20.2% vs 20.6%). B. Schematic layout of 2013 field setting showing two different row spacings. C. Concentration of oil in low chlorophyll mutant decreased by 2% in 38cm spacing (21.4% vs 22%) while there was no difference in 19cm spacing (21.3% vs 21.7%) in 2013 field. C_FIG O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=162 SRC="FIGDIR/small/744892v1_fig5.gif" ALT="Figure 5"> View larger version (22K): org.highwire.dtl.DTLVardef@68e508org.highwire.dtl.DTLVardef@94a6ccorg.highwire.dtl.DTLVardef@152a187org.highwire.dtl.DTLVardef@1eae137_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 5C_FLOATNO (greenhouse). Correlation between the level of leaf chlorophyll (x-axis: SPAD reading) and the level of immature pod or seed chlorophyll (y-axis, mg/g DW). Line represents the linear regression model. R-squared is a coefficient of determination, the percentage of the response variable variation that is explained by the linear model. Pod is labeled by the fresh weight of seeds it contained. A. Level of chlorophyll of 25-100mg pod (n=18). B. Level of chlorophyll of 100-200mg pod (n=17) . C. Level of chlorophyll of 25-100mg seed (n=17). D. Level of chlorophyll of 100-200mg seed (n=20). C_FIG O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=180 SRC="FIGDIR/small/744892v1_fig6.gif" ALT="Figure 6"> View larger version (28K): org.highwire.dtl.DTLVardef@167fd88org.highwire.dtl.DTLVardef@361472org.highwire.dtl.DTLVardef@786325org.highwire.dtl.DTLVardef@1b53855_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 6.C_FLOATNO Levels of gene expression in chlorophyll synthesis pathway. A. CHL common pathway genes; Glutamyl-tRNA reductase (GluTR). Glutamate 1- semialdehyde aminotransferase (GSA-AT). ALA dehydratase (ALAD). Uroporphyrinogen III synthase (UROS). Uroporphyrinogen III decarboxylase (UROD). Protoporphyrinogen IX oxidase (PPO). B. Mg branch; Mg-chelatase (Mgch). Magnesium-protoporphyrin IX monomethyl ester cyclase (MPEC). Protochlorophyllide reductase (POR). 3,8-divinyl protochlorophyllide a 8-vinyl-reductase (4VCR). Heme pathway; Ferrochelatase (FECH). Heme oxygenase (HO). Phytochromobilin synthase (HY). Data come from Severin et al (2010). RPKM, reads per kilobase per million mapped reads. DAF, days after flowering. The source seed is experimental line A81-356022 which was generated by introgressing G. soja (PI468916) into G. max (A81-356022). C_FIG

Plant bioengineering has generated tens of thousands of genotype-to-phenotype relationships, but this knowledge remains fragmented across narrative literature and difficult to use computationally. Inconsistent descriptions of DNA constructs, host species, and traits, including variable species names, omitted regulatory elements, and inconsistent gene symbols, impede data reuse, comparative analysis, and design-build-test-learn cycles. Here, we present the Plant Bioengineering Atlas, a literature-mined, ontology-grounded knowledge base assembled using an artificial intelligence (AI)-aided extraction pipeline. A large language model parsed open-access primary research articles to generate structured, provenance-anchored records of engineered genes, modification types, promoter-gene-terminator constructs, host species, target traits, and reported phenotypes, with every record traceable to its source. The current release contains 14,358 curated records encompassing 6,998 distinct genes across 436 plant species from 6,452 papers published between 2000 and 2026. Corpus analysis reveals that experiments are concentrated in a small group of model and crop species, disease and pathogen resistance is the most frequently engineered trait class, and constitutive regulatory parts (particularly the CaMV 35S promoter and NOS terminator) remain pervasive. Two in five records omit one or both flanking regulatory elements (i.e., promoter and terminator), while only 23.4% describe cassettes in which both elements resolve to named part classes, exposing a systematic reproducibility gap. We organize these data into a knowledge graph linking genes, constructs, species, and traits; provide access through an interactive web portal; and propose an AI-compatible documentation standard for AI-ready reporting. The Plant Bioengineering Atlas provides a foundation for data-driven hypothesis generation and AI-aided plant biodesign.

Most transgene applications require high and sustained expression, particularly in stably transformed plants. Achieving optimal transgene performance, however, depends on the combined influence of multiple genetic and regulatory factors. In previous work, we systematically evaluated the contribution of different genetic elements to transient transgene expression and demonstrated that terminators are key determinants of transgene performance by reducing transcriptional read-through and preventing transgene silencing. Here, we extend these findings by investigating the roles of terminators and introns in the expression of transgenes in stably transformed plants. Our results show that optimal transgene performance arises from the complementary actions of these two elements. Terminator choice was a major determinant of transgene expression levels, whereas introns played a critical role in maintaining expression stability. We further demonstrate a strong relationship between transgene expression levels and small RNA accumulation and show that intron-containing endogenous genes are enriched among highly expressed and stress-responsive genes, suggesting that intron-mediated protection from silencing may facilitate higher levels of gene expression and have contributed to the emergence and evolutionary retention of intron-containing genes.

O_LISiren RNAs are exceptionally abundant reproductive small interfering RNAs (siRNAs), yet whether they represent a conserved feature of angiosperm reproduction has remained unclear because siren loci lack a standardized definition and identification strategy. C_LIO_LIWe developed SirenScan, a computational framework that integrates cumulation-based and density-based analyses to identify siren loci from small RNA sequencing data. Using SirenScan, we systematically compared ovule and vegetative tissues across representative angiosperm lineages, including the early-diverging angiosperm Nymphaea colorata. C_LIO_LIWe demonstrate that the presence of siren RNAs is a conserved feature of angiosperm ovules, although the degree of expression dominance varies substantially among species. Siren loci are consistently enriched within transposable elements (TEs), while the associated TE superfamilies and cis-regulatory motifs exhibit lineage-specific diversification. In Brassicaceae, siren loci share conserved CLASSY3-associated sequence motifs, whereas other angiosperm lineages display distinct motif compositions, suggesting evolutionary diversification of Polymerase IV targeting mechanisms. C_LIO_LIOur findings establish siren RNAs as a conserved component of the angiosperm reproductive small RNA landscape and support a model in which conserved RNA-directed DNA methylation machinery is coupled with lineage-specific regulatory mechanisms and transposon landscapes to shape siren locus evolution. SirenScan provides a robust and standardized framework for comparative studies of siren RNA biology and reproductive epigenomics across plant species. C_LI

N6-methyladenosine (m6A) is the most abundant mRNA modification in eukaryotes and is essential for Arabidopsis embryogenesis. However, how m6A mRNA methylation is coordinated with other regulatory pathways during development including embryogenesis remains largely unknown. Here, we report the SWI/SNF chromatin-remodeling subunit SWI3B as a bona fide interactor of the m6A methyltransferase MTA. Like m6A writer mutants, SWI3B is required for early embryo development. We demonstrate that the interaction between MTA and SWI3B is required for MTA function during embryogenesis. MTA and SWI3B are both required to establish the correct expression pattern of WOX8 and proper auxin maxima during early embryogenesis. Transcriptome analysis of isolated embryos from mta, swi3b, and fip37 mutants identified a shared set of upregulated transcripts, including STM as well as several NAC and ERF transcription factors that are normally absent or expressed at very low levels during early embryogenesis. Embryo-specific overexpression of ANAC087 and ERF114 genes phenocopied early embryonic defects observed in mta and swi3b mutants, indicating that their ectopic expression contributes to the observed developmental phenotype. Moreover, SWI3B and MTA are both required for m6A deposition on specific developmental transcripts. Together, our findings uncover a mechanism by which chromatin remodeling and m6A-mediated RNA regulation cooperate to suppress the precocious stability of key developmental regulators, thereby contributing to the establishment of the transcriptional program required for early embryo patterning in Arabidopsis. HighlightsO_LIThe SWI/SNF subunit SWI3B is a functional interactor of the m6A methyltransferase MTA during Arabidopsis embryogenesis C_LIO_LISWI3B and MTA cooperate to establish embryo patterning, WOX8 expression, and auxin maxima C_LIO_LIMTA and SWI3B suppress precocious expression of STM, ANAC087 and ERF114 transcription factors that disrupt early embryo development C_LIO_LISWI3B links chromatin-associated regulation with m6A-mediated control of transcript stability C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=161 HEIGHT=200 SRC="FIGDIR/small/744595v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@cc0b07org.highwire.dtl.DTLVardef@1e7f8f9org.highwire.dtl.DTLVardef@8ace78org.highwire.dtl.DTLVardef@f939ff_HPS_FORMAT_FIGEXP M_FIG C_FIG

The ability of seeds to survive until dormancy recedes and the germination requirements are met is an adaptive strategy. Proteomics improves our understanding of the mechanisms that control the adaptation to environmental heterogeneity. In this study, we investigated two European beech populations from different habitats that differed in dormancy and germination traits. We found that the populations exhibited different germination strategies, which were reflected in coordinated but quantitatively different proteomic reprogramming. The Miekinia population exhibited stronger accumulation of proteins involved in nucleotide sugar biosynthesis, S-adenosylmethionine metabolism, and flavonoid biosynthesis. Enhanced nucleotide sugar biosynthesis indicates more intensive cell wall remodelling and carbohydrate metabolism, which support embryo growth and faster germination. Increased S-adenosylmethionine metabolism suggests the epigenetic and hormonal regulation of germination differences between populations. Higher flavonoid biosynthesis indicates an enhanced antioxidant capacity associated with environmental protection. In contrast, the Wisa population showed stronger accumulation of proteins involved in RNA processing, suggesting tighter post-transcriptional regulation and proteome reorganization during germination. Consistent with its deeper dormancy and later germination, the Wisa population appears to rely more on RNA-level regulation, whereas the Miekinia population prioritizes metabolic activation. These contrasting proteomic profiles likely reflect population-specific physiological strategies associated with dormancy depth and adaptation to different climatic conditions. HighlightProteomic reprogramming reveals population-specific germination strategies in European beech, linking dormancy depth with contrasting metabolic activation and RNA-level regulation during the transition from dormancy to germination.

Genome-wide association studies (GWAS) play a crucial role in unraveling the genetic foundations of complex traits in plants but are also hampered by the application of heterogeneous tools, incompatible file formats and disparate computational environments. Existing GWAS frameworks are often restricted to a single linear reference genome, limiting the capacity for the analysis of structural variations and presence/absence variations (PAV) within plant populations. These issues pose obstacles to reproducibility, scalability, and comprehensive investigations. Here, we present PlantOmicsGWAS, an open-source Python framework for reproducible plant genome-wide association analysis and genomic prediction. It integrates reference indexing, FASTQ quality control, alignment, variant calling, VCF normalization, PLINK conversion, linkage disequilibrium analysis, population-structure estimation, association testing, marker scoring, genomic prediction, and visualization within a unified Linux and HPC workflow. The framework supports conventional linear-reference analyses and includes an optional pangenome-oriented module for working with multiple assemblies and graph-derived variation. Using a Vitis benchmark dataset containing 120 accessions and 118,247 graph-derived variants, PlantOmicsGWAS reduced manual workflow fragmentation and generated standardized association outputs. This tool provides a modular and extensible platform for plant GWAS and pan-GWAS workflows while retaining compatibility with established command-line tools and common genotype formats. The GWAS workflow described herein is adaptable to a range of sequencing methods and plant genomes, bridging research on crop related issues across various biological levels, from the individual organism to entire populations. PlantOmicsGWAS implements Bayesian sparse linear mixed modeling (BSLMM) through GEMMA for multi-trait association discovery, while also supporting FaST-LMM, regression-based approaches, and machine-learning algorithms (Random Forest, XGBoost) as benchmarking alternatives. The PlantOmicsGWAS, a versatile toolkit is available at GitHub https://github.com/plantomicsgwas1-boop/PlantOmicsGwas_V1 and on Linux and HPC platform (https://pypi.org/project/PlantOmicsGwas/1.0.2/).

BackgroundThe capitulum of Asteraceae is a highly specialized inflorescence whose formation requires the coordinated regulation of multiple developmental processes, including floral organ identity and floral meristem determinacy. The LEAFY (LFY)-UNUSUAL FLORAL ORGANS (UFO) regulatory module is known to play an important role in flower development; however, naturally occurring mutations affecting this pathway have not been genetically characterized in gerbera (Gerbera hybrida). ResultsIn this study, we characterized a novel gerbera mutant identified during a commercial crossing program and named it marimo based on its green, spherical capitulum. Morphological observations revealed the repeated formation of secondary and tertiary floret-like organs within primary floret-like organs. Scanning electron microscopy showed that the epidermal structure of the green organs in marimo was similar to that of wild-type involucral bracts. RNA sequencing identified numerous differentially expressed genes between marimo and the wild type, and network and Gene Ontology analyses highlighted gene groups associated with flower development, reproductive organ differentiation, and tissue structure formation. RNA-seq analysis showed increased expression of LFY and reduced expression of GGLO1, a PISTILLATA/GLOBOSA-like B-class MADS-box gene, in the marimo mutant. RT-qPCR analysis of a segregating population further confirmed reduced GGLO1 expression in marimo-type individuals. In addition, a single-nucleotide deletion was identified in the coding region of UFO. This deletion was predicted to cause a frameshift and a premature stop codon. In selfed progeny of No. 251, the UFO genotype was fully associated with capitulum phenotype, and only individuals homozygous for the mutant allele exhibited the marimo phenotype. ConclusionsThese results indicate that the naturally occurring frameshift mutation in UFO is the strongest candidate variant underlying the marimo phenotype. RNA-seq analysis showed increased LFY expression and markedly reduced GGLO1 expression in the marimo mutant. Reduced activity of the LFY-UFO regulatory module may therefore have altered the expression of GGLO1 and other floral organ development-related genes despite the continued expression of LFY. These changes may have affected both floral organ identity and floral meristem determinacy, resulting in the formation of green involucral bract-like organs and the repeated production of floret-like organs. The marimo mutant provides a useful genetic resource for investigating capitulum development in Asteraceae and may also serve as breeding material for introducing novel ornamental traits into gerbera.

Cassava (Manihot esculenta Crantz) is a major staple crop across tropical and subtropical regions. Despite advances in genomic selection, delayed, non-flowering, and asynchronous flowering remain key bottlenecks in breeding programs. To better understand the molecular basis of flowering-time variation, we performed RNA sequencing across three genotypes with contrasting flowering phenotypes (early, late, and non-flowering) sampled at three developmental stages under contrasting light regimes in field conditions (natural light and three-hour night-break with white light). Comparative transcriptomic analysis revealed distinct gene expression patterns associated with flowering responses. Genotype comparisons with no light supplementation revealed stage-specific enrichment of biological processes. Light supplementation was associated with changes in the expression of key components of photoperiodic and circadian regulation, as well as pathways involved in flowering-time integration and hormone and sugar-related signaling. These findings suggest that coordinated changes across multiple biological pathways regulate flowering behavior in cassava. The candidate genes and expression patterns reported provide a foundation for functional studies and advance our understanding of molecular mechanisms governing flowering-time regulation in cassava.

Germination percentage is an endpoint measure and therefore does not describe when an individual seed begins visible growth or how rapidly its radicle and plumule expand. We developed a time-resolved phenotyping workflow to quantify rice seed germination continuously in shallow-water culture. A single industrial camera moved along a 1 m rail and imaged three culture boxes at 1 h intervals for up to 80 h. The archive comprised 1,062 full-frame images and 6,372 seed-level repeated observations under the six-seed field-of-view configuration. A physical grid maintained seed identity through time and enabled individual regions of interest to be extracted. Whole-seed foregrounds were obtained with a pretrained U2-Net, and a masked RGB intensity rule separated newly emerging tissue from the darker hull. For each tracked seed, projected emerging-tissue area and interval growth rate were calculated. Three representative normally germinating seeds first showed measurable tissue at 48 h, yet subsequently followed distinct trajectories: final projected areas ranged from 2,605 to 4,700 pixels and peak interval growth rates ranged from 106.88 to 287.92 pixels h-1. B-1 accumulated 63.71% of its final visible area during 72-80 h, whereas B-3 accumulated 73.51% during 60-72 h. Thus, seeds with the same observed emergence interval can differ substantially in the timing and magnitude of post-emergence expansion. The workflow converts repeated images into biologically interpretable temporal phenotypes and provides a basis for nondestructive studies of rice seed vigor and germination heterogeneity.