Search Results (284)

Background/Objectives: The basic helix–loop–helix (bHLH) transcription factor family regulates plant development, metabolism, and stress responses. Yet, its genome-wide composition remains unexplored in Lilium bakerianum var. rubrum (LBVR), an ornamental lily valued for its floral traits. This study aimed to identify, classify, and profile the bHLH family in LBVR using full-length transcriptomic resources. Methods: PacBio HiFi full-length transcriptome sequencing was combined with Illumina RNA-seq for accurate structural annotation and expression quantification. Candidate bHLHs were identified by iTAK and HMMER-Pfam, and their physicochemical properties, secondary structures, motifs, and phylogenetic positions were examined. Expression patterns were analyzed across four floral stages (bud, initial bloom, full bloom, and late bloom). Results: A total of 113 high-confidence bHLH genes were identified, with ~90% successfully annotated. The proteins displayed variation in molecular weight, isoelectric point, structural features, and motif composition. Phylogenetic analysis placed them into 13 clades consistent with Arabidopsis subfamilies, revealing lineage-specific expansions and contractions. Expression profiling showed that 95 genes were active in at least one stage, with two transcriptional waves: a strong bud-to-initial-bloom activation and a secondary wave spanning anthesis. Seventeen genes were expressed exclusively at the bud stage, suggesting roles in early floral-organ initiation and pigmentation. Conclusions: This work provides the first genome-wide characterization of bHLHs in LBVR. The integrated sequencing approach generated a robust catalogue and developmental expression map, offering candidates for functional studies and resources for breeding in lilies. Full article

Magnoliids represent one of the most basal lineages within angiosperms, and their ancestral floral morphology provides crucial insights into the evolution of flowers in angiosperms. MCM1-AGAMOUS-DEFICIENS-SRF (MADS)-box transcription factors play crucial roles in specifying floral organs. To understand their evolutionary history and functional divergence in magnoliids, we identified MADS-box genes, and conducted phylogenetic and expression analysis in 33 magnoliids and 8 other angiosperm plants. A total of 1310 MADS-box genes were identified and classified into Type I and Type II. The expansion of MADS-box genes in magnoliids mainly arose from whole-genome duplication events. In Liriodendron chinensis and Chimonanthus praecox, we identified floral homeotic MADS-box genes that are orthologous to the ABCDE model genes of floral organ identity determination. The broad expression pattern of A and B genes in floral organs and overlapping activity of ABCDE-model genes are consistent with the “shifting−fading borders” scheme proposed in basally diverging angiosperm lineages. Our results not only elucidate the driving forces underlying the diversification of MADS-box genes in magnoliids, but also shed light on the evolutionary models of floral development in angiosperms. Full article

Lycoris longituba produces a single flower bearing six tepals. The double-petaled phenotype of L. longituba has gained significant interest in China due to its ornamental and commercial value in tourism industries. This double-petal phenotype, characterized by stamen petalization, shows improved esthetic characteristics compared with conventional single-petal form. However, the molecular mechanisms underlying this floral trait remain largely undefined. In this study, RNA-based comparative transcriptomic analysis was performed between single- and double-petaled flowers of L. longituba at the fully opened flower stage. Approximately 13,848 differentially expressed genes (DEGs) were identified (6528 upregulated and 7320 downregulated genes). Functional annotation through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed several DEGs potentially involved in double-petal development. Six candidate genes, including the hub genes LlbHLH49, LlNAC1, LlSEP, LlTIFY, and LlAGL11, were identified based on DEG functional annotation and weighted gene co-expression network analysis (WGCNA). Transcription factors responsive to phytohormonal signaling were found to play a pivotal role in modulating double-petal development. Specifically, 123 DEGs were involved in phytohormone biosynthesis and signal transduction pathways, including those associated with auxin, cytokinin, gibberellin, ethylene, brassinosteroid, and jasmonic acid. Moreover, 521 transcription factors (TFs) were identified, including members of the MYB, WRKY, AP2/ERF, and MADS-box families. These results improve the current understanding of the genetic regulation of the double tepal trait in L. longituba and offer a base for future molecular breeding strategies to enhance ornamental characteristics. Full article

CRABS CLAW (CRC) is a member of the plant-specific YABBY transcription factor family, defined by the presence of a C2C2 zinc-finger domain and a C-terminal YABBY domain. CRC is essential for proper floral development, functioning in the termination of the floral meristem, maintenance of adaxial–abaxial polarity within the gynoecium, and regulation of nectary and leaf morphogenesis. CRC orchestrates its diverse regulatory functions through interaction networks comprising other transcription factors and plant developmental regulators, including chromatin-modifying enzymes and proteins involved in auxin biosynthesis, transport, and signaling. The roles of genes and proteins interacting with CRC or CRC have been characterized in several model plant species, and the number of identified CRC/CRC-associated interactions continues to expand, revealing both species-specific and conserved functional roles across angiosperms. Many functions of CRC and its interacting partners have been elucidated through the analysis of anatomical and physiological phenotypes associated with specific gene mutations. The functional roles of CRC in plant development appear to have been acquired progressively through evolutionary diversification. These evolutionary changes have been associated with the relative conservation of CRC gene copy number and a predominant role of mutations occurring in non-coding regulatory regions. These properties are attributed to the relatively limited number of genes comprising the CRC regulatory network and the capacity to induce dosage-dependent effects via the emergence of novel proteins with overlapping or analogous functions. The identification and functional characterization of CRC transcription factors across diverse plant species has advanced rapidly in recent years, yet a comprehensive synthesis of these findings has not been presented in a dedicated article. Therefore, this study reviews the current knowledge on CRC transcription factors, with a focus on their identification, expression patterns, and functional roles in plant development. Full article

The initiation, development, and morphological construction of floral organs constitute a highly intricate process, involving numerous factors and their interactions. MADS-box genes are key regulators of developmental processes and are consequently the most extensively studied gene family in floral organ research. By synthesizing current understanding of the regulatory roles of MADS-box genes in the initiation, differentiation, and morphogenesis of floral organ, this review provides novel insights into the floral development program and the general transcriptional regulatory mechanisms of this gene family. It also offers a reference for further in-depth exploration of this gene family and the refinement of theories governing floral development regulation. Full article

Background/Objectives: The TOPLESS (TPL) and TOPLESS-related (TPR) proteins represent a highly conserved class of transcriptional co-repressors in plants, playing pivotal roles in modulating growth, development, and stress responses through the repression of key transcriptional regulators. However, a comprehensive genome-wide analysis of the TPL/TPR gene family and its involvement in stress responses remains unexplored in cotton. Methods: In this study, 60 TPL/TPR genes were identified from the genomes of ten Gossypium species via bioinformatics approaches, and their protein physicochemical properties, gene structures, phylogenetic relationships, cis-regulatory elements, and expression profiles were characterized. Results: Chromosomal localization and collinearity analyses revealed that segmental duplication events have contributed to the expansion of the TPL/TPR gene family. Further examination of exon–intron architectures and conserved motifs highlighted strong evolutionary conservation within each TPL/TPR subgroup. Expression profiling demonstrated that TPL/TPR genes exhibit tissue-specific expression patterns, with particularly high transcript abundance in floral organs (e.g., petals and stigmas). Cis-element analysis suggested their potential involvement in multiple stress-responsive pathways. Notably, GhTPL3 showed high constitutive expression across various tissues and under stress conditions, with the most pronounced up-regulation under salt stress. Functional validation via Virus-Induced Gene Silencing (VIGS) confirmed that GhTPL3 silencing significantly impairs cotton salt stress tolerance, underscoring its critical role in abiotic stress adaptation. Conclusions: Our findings provide novel insights into the functional diversification and regulatory mechanisms of the TPL/TPR family in cotton, offering a valuable genetic resource for breeding stress-resilient cotton varieties. Full article

Carpel number has been recognized as a critical factor influencing fruit size, ultimately determining yield and economic efficiency. The WUSCHEL (WUS) protein is essential for maintaining stem cell homeostasis in the floral meristem. Its expression level directly influences the size of the floral meristem (FM), thereby determining the number of floral organs in Arabidopsis thaliana, Solanum lycopersicum, and Cucumis sativus. While its role remained largely unexplored in grapevine (Vitis vinifera). This study cloned the VvWUS gene from the polycarpic grape cultivar ‘Jizaomi’. Transgenic tomato lines expressing VvWUS heterologously exhibited accelerated floral transition, enhanced carpel/floral organ initiation, and had significantly higher locule numbers relative to wild type. Furthermore, direct binding of VvWUS to the VvAGAMOUS (VvAG) promoter and activation of VvAG expression were demonstrated through yeast one-hybrid (Y1H) and dual-luciferase (LUC) assays. These findings elucidated the molecular function of VvWUS in grape carpel development, providing a foundational basis for molecular breeding strategies targeting large-berry grape varieties. Full article

Litchi (Litchi chinensis Sonn.) is a kind of evergreen fruit tree with good flavor and taste which has high economic value. Sufficiently low temperature in winter is essential for the successful flower formation of litchi. Therefore, in the context of global warming, litchi often experiences unstable flower formation, ultimately resulting in a decrease in litchi production. Our previous research has highlighted the pivotal role of the LcFT1 gene in regulating the flower formation of litchi and identified two AP1 homologous genes associated with LcFT1 (named LcAP1-1 and LcAP1-2) based on RNA-Seq and weight gene co-expression network analysis (WGCNA). In this study, the functions of the two AP1 homologous genes in regulating flowering time were investigated. Result showed that LcAP1-1 and LcAP1-2 were expressed in all litchi tissues. LcAP1-1 was more highly expressed in mature leaves compared to other tissues, while the LcAP1-2 has the highest expression level in flower buds. Both of them exhibited upregulation in the terminal bud of litchi under low temperature. The expression of LcAP1-1 and LcAP1-2 was highly correlated with the initiation of flower buds and the development of flower organs. They increased gradually during the floral initiation but decreased gradually during flower bud development. The transgenic tobacco of LcAP1-2 flowered about 55 days earlier than wild-type, while tobacco overexpressing the LcAP1-1 gene had no significant changes in flowering time compared to the wild-type. These results indicate that the two genes have divergent regulatory functions, and that the LcAP1-2 gene may be involved in the regulation of flower transformation and flower organ development in litchi. Our research will further reveal the molecular regulatory mechanisms of flower formation in litchi and will also provide theoretical guidance for the molecular breeding of litchi. Full article

The WUSCHEL-related homeobox (WOX) gene family is integral to plant growth and development. Here, we identified 14 CcWOX genes from the Cinnamomum camphora genome and analyzed their phylogeny, conserved features, and expression patterns. Phylogenetic inference grouped CcWOX into the Ancient, Intermediate, and WUS clades, consistent with other plant lineages. Expression profiling across seven tissues/organs, together with qRT-PCR validation, revealed tissue-biased expression for several members (e.g., floral or root enrichment), suggesting gene-specific roles during development. Using AlphaFold3, we predicted monomeric structures for CcWOX proteins and an interface model compatible with an interaction between CcWOX3 and CcLBD33. Consistently, bimolecular fluorescence complementation (BiFC) in Nicotiana benthamiana detected nuclear YFP signals for cEYFP-CcWOX3 + nEYFP-CcLBD33 relative to appropriate negative controls, confirming a physical interaction in plant cells. While these findings support a putative WOX–LBD interaction module in C. camphora, the regulatory functions remain to be established. Overall, this work provides a framework for dissecting the CcWOX family in C. camphora and illustrates how AI-assisted structure prediction can be integrated with cell-based assays to accelerate hypothesis generation in plant developmental biology. Full article

Chimonanthus praecox, a traditional ornamental plant in China, is admired for its ability to bloom during the cold winter season and is recognized as an outstanding woody cut flower. MADS-box genes encode transcription factors essential for plant growth and development, with key functions in regulating flowering time and the formation of floral organs. In this study, 74 MADS-box genes (CpMADS1–CpMADS74) were identified and mapped across 11 chromosomes, with chromosome 1 harboring the highest number (13 genes) and chromosome 3 the fewest (3 genes). Physicochemical property analysis revealed that all CpMADS proteins are hydrophilic and predominantly nuclear-localized. Phylogenetic analysis classified these genes into Type I and Type II subfamilies, highlighting a clear divergence in domain structure. Eighty simple sequence repeat (SSR) loci were detected, with dinucleotide repeats being the most abundant, and the majority located in Type II MADS genes. From 23 C. praecox samples, 10 polymorphic SSR markers were successfully developed and PCR-validated, enabling a cluster analysis that grouped these cultivars into three distinct clusters. This study offers significant insights into the regulation of flowering, floral organ development, genetic linkage map construction, and the application of marker-assisted selection in C. praecox. Full article

Although the allocation of biomass among floral organs reflects critical trade-offs in plant reproductive strategies, the scaling relationships governing biomass allocations remain poorly resolved, particularly in flowers. Here, we report the fresh mass scaling allocation patterns among four floral organs (i.e., sepals, petals, stamens, and carpels), and the two subtending structural components (i.e., the pedicel and receptacle) of 497 flowers of the hypogynous Rosa chinensis var. minima (miniature rose) using reduced major axis protocols. The two-parameter Weibull probability density function was also applied to characterize the distributions of floral organ mass, and revealed skewed tendencies in all six measured traits. The results show that the numerical values of the scaling exponents (α) for all pairwise power-law relationships significantly exceeded unity (α > 1), indicating disproportionate investments in larger floral structures with increasing overall flower size. Specifically, the scaling exponent of corolla fresh mass vs. calyx fresh mass was α = 1.131 (95% confidence interval [CI]: 1.086, 1.175), indicating that petal investment outpaces sepal investment as flower size increases. Reproductive organs also exhibited significant disproportionate investments (i.e., allometry): the collective carpel (gynoecium) fresh mass scaled allometrically with respect to the collective stamen (androecium) mass (α = 1.062, CI: 1.028, 1.098). Subtending axial structures (pedicel and receptacle) also had hyperallometric patterns, with pedicel mass scaling at α = 1.167 (CI: 1.106, 1.235) with respect to receptacle mass. Likewise, the combined fresh mass of all four foliar homologues (sepals, petals, androecium, and gynoecium) scaled disproportionately with respect to the biomass of the two subtending axial structures (α = 1.169, CI: 1.126, 1.214), indicating a prioritized resource allocation to reproductive and display organs. These findings are in accord with hypotheses positing that floral display traits, such as corolla size, primarily enhance pollen export by attracting pollinators, while maintaining fruit setting success through coordinated investment in gynoecium development. The consistent hyperallometry across all organ pairwise comparisons underscores the role of developmental integration in shaping floral architecture in Rosaceae, as predicted by scaling theory. By integrating morphometric and scaling analyses, this study proposes a tractable methodology for investigating floral resource allocation in monomorphic-flowering species and provides empirical evidence consistent with the adaptive patterns of floral traits within this ecologically and horticulturally significant lineage. Full article

To elucidate the molecular mechanisms underlying anther abortion in celery male sterile lines, this study investigates the morphological differences of floral organs and differential gene expression patterns between two lines at the flowering stage. Using the male sterile line of celery ‘QCBU-001’ and the fertile line ‘Jinnan Shiqin’ as materials, anther structure was analyzed by paraffin sections, and related genes were detected using transcriptome sequencing and qRT-PCR. The results indicated that the anther locules were severely shrunken at maturity in the sterile lines. The callose deficiency led to abnormal development of microspores, preventing the formation of mature pollen grains and ultimately leading to complete anther abortion. The transcriptome results revealed that 3246 genes were differentially expressed in sterile and fertile lines, which were significantly enriched in pathways such as starch and sucrose metabolism and phenylpropanoid biosynthesis. Additionally, differential expression patterns of transcription factor families (MYB, bHLH, AP2, GRAS, and others) suggested their potential involvement in regulating anther abortion. Notably, the expression level of callose synthase gene AgGSL2 was significantly downregulated in sterile anthers, which might be an important cause of callose deficiency and pollen sterility. This study not only provides a theoretical basis for elucidating the molecular mechanism underlying male sterility in celery but also lays a foundation for the utilization and improvement of male sterile lines in vegetable hybrid breeding. Full article

The quality of Crocus sativus L. flowers, beyond their stigmas, is influenced by the presence of bioactive metabolites also in their floral bio-residues. Given the effect of climatic and soil variables on these bioactive compounds, the aim of this research was to develop an agroecological zoning of saffron crop areas within the Protected Designation of Origin (PDO) La Mancha region (Castilla-La Mancha, Spain) by integrating the floral metabolite content with climatic and soil variables. To achieve this, a total of 173 samples were collected during the 2022 and 2023 harvests and analyzed via RP-HPLC-DAD to determine crocins, picrocrocin, kaempferols, and anthocyanins. Two new indices, Cropi (crocins + picrocrocin) and Kaeman (kaempferols + anthocyanins), were defined to classify flowers into four quality categories (A–D). High-quality classifications (A and B) were consistently associated with plots grouped in the meteorological stations of Ontur, El Sanchón, and Bolaños, indicating favorable edaphoclimatic conditions and climatic parameters, such as moderate temperatures and reduced humidity, for metabolite biosynthesis. In contrast, plots included in the meteorological stations of Tarazona and Pedernoso were mostly assigned to lower categories (C and D). Spatial analysis using thematic maps revealed that areas with an intermediate carbonate content, less calcareous soils, and higher organic matter levels were linked to higher flower quality. These findings highlight the influence of soil characteristics and climate, with distinct seasonal contrasts, that positively influence metabolite synthesis and flower quality. Full article

Peanut (Arachis hypogaea L.) is a globally important oilseed cash crop, yet its limited genetic diversity and unique reproductive biology present persistent challenges for conventional crossbreeding. Traditional breeding approaches are often time-consuming and inadequate, mitigating the pace of cultivar development. Essential for double fertilization and programmed cell death (PCD), DUF679 membrane proteins (DMPs) represent a membrane protein family unique to plants. In the present study, a comprehensive analysis of the DMP gene family in peanuts was conducted, which included the identification of 21 family members. Based on phylogenetic analysis, these genes were segregated into five distinct clades (I–V), with AhDMP8A, AhDMP8B, AhDMP9A, and AhDMP9B in clade IV exhibiting high homology with known haploid induction genes. These four candidates also displayed significantly elevated expression in floral tissues compared to other organs, supporting their candidacy for haploid induction in peanuts. Subcellular localization prediction, confirmed through co-localization assays, demonstrated that AhDMPs primarily localize to the plasma membrane, consistent with their proposed roles in the reproductive signaling process. Furthermore, chromosomal mapping and synteny analyses revealed that the expansion of the AhDMP gene family is largely driven by whole-genome duplication (WGD) and segmental duplication events, reflecting the evolutionary dynamics of the tetraploid peanut genome. Collectively, these findings establish a foundational understanding of the AhDMP gene family and highlight promising targets for future applications in haploid induction-based breeding strategies in peanuts. Full article

Camellia azalea is an endemic species within the genus Camellia that exhibits the trait of summer flowering, which is of significant ornamental and research value. Nevertheless, research on the regulatory mechanisms of flower formation in C. azalea is still limited, so in this study, transcriptome sequencing and analysis of endogenous hormone contents were conducted at three distinct growth stages: floral induction, floral organ maturation, and anthesis. Illumina sequencing yielded a total of 20,643 high-quality unigenes. Comparative analyses of representative samples from the three growth stages identified 6681, 1925, and 8400 differentially expressed genes (DEGs), respectively. These DEGs were further analyzed for functional enrichment using the GO and KEGG databases. Additionally, core genes from each flowering pathway underwent expression pattern analysis and network diagram construction. This revealed that the flower development process in C. azalea is linked to the specific expression of the genes involved in the photoperiod, temperature, and autonomous pathways and is subject to comprehensive regulation by multiple pathways. Further analysis of the dynamic trends of five endogenous hormone contents and plant hormone signal transduction genes revealed significant differences in the requirements of endogenous hormones, such as gibberellins and indoleacetic acid, by C. azalea at distinct growth stages. Additionally, the majority of genes on the phytohormone signal transduction pathway demonstrated a high correlation with the changes in the contents of each hormone. The present study integrates physiological and molecular approaches to identify key genes and metabolic pathways that regulate the summer flowering of C. azalea, thereby laying a theoretical foundation for further investigations into its flowering mechanism and related functional genes. Full article