Search Results (99)

Taraxacum kok-saghyz (TK), the rubber dandelion, is an emerging crop offering potential for sustainable natural rubber production independent of tropical climates. Successful domestication of TK requires a mechanistic understanding of its reproductive biology, yet floral anatomy, sporogenesis, and gametogenesis remain poorly characterized. We hypothesized that TK’s reproductive development follows the general patterns of sexually reproducing diploid Taraxacum species and other Asteraceae, distinguishable from the irregular meiosis reported in apomictic taxa. Here, using light and scanning electron microscopy across multiple developmental stages, we describe the floral and inflorescence anatomy, as well as sporogenesis and gametogenesis in TK. Anther development in TK predominantly follows the simultaneous microsporogenesis pattern, typical of eudicots, producing regular tetrahedral tetrads. Notably, we also observed occasional successive-type events resulting in dyads and tetragonal tetrads, indicating a previously unreported developmental variation within the species, culminating in mature tricellular pollen. We detail key reproductive structures, including anther wall layers, ovary mesophyll differentiation, and the presence of a micropylar obturator. The meiotic behavior and gametophyte development observed in TK are consistent with those of diploid, sexually reproducing Taraxacum species and other members of the Asteraceae, in contrast to the irregular meiosis reported in Taraxacum apomictic taxa. These newly described morphoanatomical details on reproductive aspects will inform breeding strategies and advance our understanding of pollination, fertilization, and seed development in TK. Full article

To estimate leaf area, the length-width method, also called the Montgomery equation, has been widely used. It is an empirical formula stating that within a given species, the area of a leaf is proportional to the product of its length and width. Although the formula is known to be applicable to a variety of simple leaves and leaflets, its applicability to compound leaves has only been investigated on a limited range of leaf forms and economically important crops. In this study, we investigated whether this method is broadly applicable to compound leaves of diverse forms. We measured 20 compound-leaved species including various leaf shapes (ternate, biternate, triternate, palmate, pedate, and pinnate leaves) as well as life forms (trees, herbs, and woody and herbaceous lianas). Our data cover diverse taxa, including both Ranunculales and core eudicots (Fabales, Rosales, Fagales, Vitales, Apiales, Lamiales, Asterales, and Dipsacales). The results show that the length-width method is applicable to all types of compound leaves investigated (slope [i.e., Montgomery parameter]: 0.298–1.035; R² = 0.928–0.996). These results indicate that a compound leaf can be considered equivalent to a simple lobed leaf when applying the length-width method. Full article

Current industrial sources of tocotrienols are almost entirely composed of tropical monocots. However, recent reports have observed significant tocotrienol (T3) contents in eudicot families, including Passifloraceae. While passion fruits are also tropical, their cultivation is not strictly limited to rainforests, and seeds are often a by-product of fruit processing. To elucidate tocochromanol production in the Passifloraceae family, seeds (54 samples representing 18 species) were gathered from botanical gardens worldwide. Ultrasound-assisted extraction in ethanol (UAEE) was compared with the standard saponification protocol as a greener alternative. Tocotrienols constituted a major percentage (48–91%) of Passifloraceae species’ seed tocochromanols, and γ-T3 (12–53%) and δ-T3 (8–68%) were major contributors. Although a higher δ-T3 content was observed in some Passiflora species, it was less consistent than the γ-T3 content between and within species. The highest total tocochromanol content was observed in P. subpeltata (28.98 ± 5.83 mg 100 g⁻¹ dry weight). The UAEE protocol recovered tocotrienols and tocopherols at degrees similar to those of saponification (100% and 93%, respectively). Therefore, UAEE could also be proposed for the effective recovery of these valuable phytochemicals from by-products of Passiflora fruits. Full article

Plants from the eudicot Celastraceae family are primarily cultivated for ornamental use due to their colourful autumn foliage, and, as such, their chemical composition is rarely investigated. In total, 125 samples from, altogether, 40 shrub, vine and tree species (Catha, Celastrus, Euonymus, Gymnosporia, Maytenus, Parnassia, and Tripterygium) were investigated to confirm tocotrienol dominance in the family, which was observed in the initial screenings. The tocochromanol–tocopherol (T) and tocotrienol (T3) contents ranged from 3.04 to 66.22 mg 100 g⁻¹ dw. Almost all the samples were tocotrienol-dominated (50.1–98.5% of total tocochromanols), except for Parnassia. The two most prevalent compounds were γ-T3 and α-T3. Most Euonymus species’ seeds contained primarily α-T3 (16.2–86.0% of total tocochromanols) and tocopherol (up to 35.0%), while the other species had higher γ-T3 (36.0–87.2%) and tocopherol (up to 29.9%) contents, except the Parnassia samples, which contained primarily γ-T and δ-T. The highest total tocochromanol content was observed in E. scandens, but it was highly variable. The content of α-T3 was less variable than γ-T3 (coefficients of variation of 0.74 and 1.46, respectively). This study shows that tocotrienols are predominant in the Celastraceae family. A streamlined ethanolic extraction protocol was evaluated and deemed suitable for routine screening and, potentially, bioactive extraction. Full article

A pair of connected flowers preserved in a mid-Cretaceous (early Cenomanian) Myanmar amber is described and named Antiquigemina pilosa Wang and Li gen. et sp. nov. Antiquigemina pilosa has bisexual flowers with a calyx of at least 3 sepals, a corolla of 5 petals, a whorl of at least 4 stamens and a tricarpellate pistil with a semi-inferior ovary. The differences in style divergence and calyx presence between paired flowers indicate different developmental stages. Considering that differentiated calyx and corolla and pentamery of corolla are features frequently observed in core eudicots, we propose treating Antiquigemina pilosa, which has a pentamerous perianth and differentiated sepals and petals, as an earlier representative of core eudicots. Antiquigemina pilosa provides first-hand evidence for the early diversification of core eudicots. Full article

Caleosins (CLOs) or peroxygenases (PXGs), a class of structural proteins of lipid droplets (LDs), comprise a small family of multifunctional proteins widely involved in oil accumulation, organ development, and stress responses. Despite the proposal of two clades termed H and L in Arabidopsis thaliana, their evolution in the order Brassicales has not been well established. In this study, the first genome-wide analysis of the caleosin family was conducted in papaya (Carica papaya), a Caricaceae plant without any recent whole-genome duplication (WGD). A high number of five members representing both H and L clades were identified from the papaya genome. Further identification and comparison of 68 caleosin genes from 14 representative plant species revealed seven orthogroups, i.e., H1–4 and L1–3, where H1 and L1 have already appeared in the basal angiosperm Amborella trichopoda, supporting their early divergence before angiosperm radiation. Five CpCLO genes belong to H1 (1) and L1 (4), and extensive expansion of the L1 group was shown to be contributed to by species-specific tandem and transposed duplications, which may contribute to environmental adaptation. Orthologous and syntenic analyses uncovered that lineage-specific expansion of the caleosin family in Brassicales relative to A. trichopoda was largely contributed to by tandem duplication and recent WGDs, as well as the ancient γ whole-genome triplication (WGT) shared by all core eudicots. Independent gain or loss of certain introns and apparent expression divergence of caleosin genes were also observed. Tissue-specific expression analysis showed that CpCLO2 and −5 are constitutively expressed, whereas others appear to be tissue-specific, implying function divergence. Interestingly, the H-forms CpCLO1 and RcCLO1 were shown to exhibit similar expression profiles to most oleosin genes that are preferentially expressed oil-rich tissues such as seeds/endosperms, shoots, and calluses, implying their putative involvement in oil accumulation, as observed in Arabidopsis. The results obtained from this study provide a global view of CpCLO genes and insights into lineage-specific family evolution in Brassicales, which facilitates further functional studies in papaya and other non-model species. Full article

Glutaredoxins (GRXs) are important proteins in plant development and environmental adaptation. Despite extensive characterization of GRX gene family members in various plant species, limited research has been conducted on the identification and functional analysis of GRXs in the economically important Solanaceae family pepper (Capsicum annuum). This study identified 35 typical GRX genes in pepper and categorized them into three distinct groups: CC-, CGFS-, and CPYC-type, based on the phylogenetic topology, which was consistent with motif or domain arrangement, and gene structures. Furthermore, the determination of ω values indicated that purifying selection was a significant factor in the evolutionary diversification of GRX genes in the eudicot family. Intra-genome investigations demonstrated that both segmental and tandem duplications were involved in the expansion of CaGRX genes. Moreover, examination of collinearity within the Solanaceae family revealed 53 orthologous pairs of GRX genes. Additionally, prediction of cis-regulatory elements and analysis of expression profiles revealed the significant involvement of GRX genes in plant stress response, specifically in relation to hypoxia and submergence. Subsequent subcellular localization examination suggested CaGRX may be involved in the endomembrane system and regulation of oxidative balance in plants. Collectively, these findings enhance our comprehension of the structural and functional properties of GRX in pepper, and establish a groundwork for subsequent functional characterization of the CaGRX genes. Full article

RNA-directed DNA methylation (RdDM) is an epigenetic mechanism involved in several biological processes in plants, requiring complex machinery including the chromatin remodeling protein CLASSY (CLSY). The CLSY family regulates global and locus-specific DNA methylation and was initially identified in Arabidopsis thaliana. Despite reports in other plants, detailed knowledge about CLSY proteins in soybean is scarce. In this work, we used profile hidden Markov models (profile HMMs) specifically constructed for CLSY detection to identify new members in soybean and to analyze their phylogenetic relationships across bryophyte, basal angiosperm, basal eudicot, monocots, and eudicots. We identified two new candidates for CLSY1-2 and one for DRD1 in soybean and, for the first time, detected CLSY and DRD1 genes in Aquilegia coerulea. Phylogenetic analysis indicated two main CLSY groups: one similar to Arabidopsis CLSY1-2 and another to CLSY3-4. Gene duplication analysis demonstrated that whole-genome duplication/segmental duplication events contributed to CLSY family expansion in soybean. RT-qPCR analysis showed that CLSY and five other epigenetic regulator genes had stress-modulated expression during soybean germination under salt and osmotic stress, with variation among cultivars. Our findings enhance comprehension of the evolutionary dynamics of the CLSY family and furnish insights into their response to abiotic stress in soybean. Full article

Spring ephemerals have different pollination strategies to avoid the rareness and/or low activity of insect pollinators caused by low temperature in early spring. However, limited research has been conducted on the effects of elaborate petals and the pseudonectaries on petals on pollinator attraction. We examined the role of the elaborate petals and the pseudonectaries in pollinator attractions of the spring ephemeral Eranthis stellata (Ranunculaceae) using a combination of observational and experimental approaches. The results indicated that the color contrast created by the yellow pseudonectaries that did not secrete nectar on the white petals, was more attractive to both bees and flies as nectar guides, but only bees with relatively longer tongues could access nectar at the base of the petal tubes. Also, the pseudonectaries were food deception for fly visitors. Food deception as a mechanism to increase the efficiency of pollination has not been reported for Ranunculaceae or other basal eudicots. Full article

Heat shock proteins (HSPs) function as molecular chaperones to maintain protein homeostasis and repair denatured proteins, counteracting abiotic stresses. Despite their functional importance, a systematic bioinformatics analysis of the HSP gene family was lacking in Poaceae. In this study, we revealed that HSPs are widely distributed from algae to eudicots, with varying numbers in Poaceae including Oryza, Triticum, and Panicum. Gene duplication events, particularly dispersed duplication (DSD), tandem duplication (TD), and genome polyploidization, have probably driven the increased number of HSP genes and the expansion of HSP family proteins. Gene Ontology (GO) annotation analyses suggested their conserved functions. Promoter cis-acting element analyses indicated that their expression levels were tightly regulated by abiotic stresses. We validated that many collinear HSP genes are indeed regulated by the cold stress by analyzing the published RNA-seq data in rice, maize, and wheat, and performing RT-qPCR in rice. Our findings shed light on the role of HSPs in the abiotic stress response, laying the groundwork for further exploration of HSP functions in Poaceae. Full article

cangas are iron-rich outcrops where rupestrian fields develop in the Carajás Mountain Range (CMR). canga formations are ancient ecosystems characterized by high levels of endemic and threatened plant species that thrive on iron-rich substrates in the southeastern Amazon uplands. The recent taxonomic validation of these species enables more accurate distribution modeling across past, present, and future time scales. This work presents a comprehensive palynological database for the Amazon canga vegetation, resulting from extensive field and herbarium surveys, as well as the compilation and taxonomic validation of species in the Carajás Mountain Range (CMR). This atlas includes 204 plant species: 10 ferns and lycophytes, 62 monocots, and 132 eudicots and magnoliids (mainly herbs, lianas, and trees). Most flowering plants are pollinated by bees, with secondary pollination by other insects and wind. The taxa co-occur in two geoenvironments: (1) forested slopes and caves over plinthosols and ferralsols and (2) slopes with canga vegetation over plinthosols. Seventeen species are potential domesticates used by Indigenous peoples. This highlights canga vegetation as a unique and diverse ecosystem with various survival strategies, emphasizing the need for precise habitat definitions in paleoenvironmental and paleoclimate reconstructions. This atlas provides a valuable reference for palynological studies, enhancing the vegetation reconstruction, climate history analysis, pre-Columbian influences on vegetation patterns, and ecological monitoring. Full article

Proteins of the PF10950 family feature the DUF2775 domain of unknown function. The most studied are specific tissue (ST) proteins with tandem repeats, which are putative precursors of cyclopeptide alkaloids. Here, we study uncharacterised short ST (SST) proteins with the DUFF2775 domain by analysing 194 sequences from 120 species of 39 taxonomic families in silico. SST proteins have a signal peptide and their size and several other characteristics depend on their individual taxonomic family. Sequence analyses revealed that SST proteins contain two well-conserved regions, one resembling the ST repeat, which could constitute the core of cyclopeptide alkaloids. We studied the unique SST1 gene of Arabidopsis thaliana, which is adjacent to and co-expressed with a gene encoding a protein with a BURP domain, associated with cyclopeptide production. The empirical analysis indicated that the SST1 promoter is mainly activated in the roots, where most of the transcripts accumulate, and that the SST1 protein accumulates in the root vascular cambium. At the cellular level, SST fused to GFP appears in vesicles that co-localise with the endoplasmic reticulum and the vacuole. Thus, SSTs are a new type of PF10950 protein found in core eudicots with two conserved regions that could be involved in root biology. Full article

LEA_5 domain-containing proteins constitute a small family of late embryogenesis-abundant proteins that are essential for seed desiccation tolerance and dormancy. However, their roles in non-seed storage organs such as underground tubers are largely unknown. This study presents the first genome-scale analysis of the LEA_5 family in tigernut (Cyperus esculentus L.), a Cyperaceae plant producing desiccation-tolerant tubers. Four LEA_5 genes identified from the tigernut genome are twice of two present in model plants Arabidopsis thaliana and Oryza sativa. A comparison of 86 members from 34 representative plant species revealed the monogenic origin and lineage-specific family evolution in Poales, which includes the Cyperaceae family. CeLEA5 genes belong to four out of five orthogroups identified in this study, i.e., LEA5a, LEA5b, LEA5c, and LEA5d. Whereas LEA5e is specific to eudicots, LEA5b and LEA5d appear to be Poales-specific and LEA5c is confined to families Cyperaceae and Juncaceae. Though no syntenic relationship was observed between CeLEA5 genes, comparative genomics analyses indicated that LEA5b and LEA5c are more likely to arise from LEA5a via whole-genome duplication. Additionally, local duplication, especially tandem duplication, also played a role in the family expansion in Juncus effuses, Joinvillea ascendens, and most Poaceae plants examined in this study. Structural variation (e.g., fragment insertion) and expression divergence of LEA_5 genes were also observed. Whereas LEA_5 genes in A. thaliana, O. sativa, and Zea mays were shown to be preferentially expressed in seeds/embryos, CeLEA5 genes have evolved to be predominantly expressed in tubers, exhibiting seed desiccation-like accumulation during tuber maturation. Moreover, CeLEA5 orthologs in C. rotundus showed weak expression in various stages of tuber development, which may explain the difference in tuber desiccation tolerance between these two close species. These findings highlight the lineage-specific evolution of the LEA_5 family, which facilitates further functional analysis and genetic improvement in tigernut and other species. Full article

Angiosperms are the largest group of land plants with ~375,000 species, which are classified into ~416 families and ~13,000 genera; they exhibit tremendous morphological and physiological diversities and are important members of diverse terrestrial and aquatic ecosystems. Angiosperms have attracted continuous efforts to describe and understand these diversities in a framework of interrelationships—the phylogeny, which provides strong support for angiosperm classifications and relies on morphological, anatomical, and increasing molecular markers. Today, great advances in sequencing technology have led to the generation of tens of thousands of gene sequences for individual species, facilitating angiosperm phylogenetic reconstruction with high resolution at both deep and shallow levels. In this review, we present recent insights into angiosperm phylogeny based on relatively large numbers of nuclear genes, encompassing the ordinal scale of early-divergent and backbone branches, eudicots and their major subclades, asterids and rosids, as well as monocots. We further delve into intra-order cases such as Caryophyllales (Eudicots) and Alismatales (Monocots), along with intra-family relationships for some of the largest families (e.g., Asteraceae, Orchidaceae, Fabaceae, and Poaceae) and those with economic importance (such as Brassicaceae, Solanaceae, Cucurbitaceae, and Rosaceae). Furthermore, we briefly highlight the importance of nuclear phylogeny in addressing key evolutionary questions, including the origin and divergence of angiosperms, the evolution of morphological and other characters, gene duplication and other aspects of gene family evolution. Finally, we discuss possible future trends of angiosperm phylogenomics. Full article

Calcium-dependent protein kinases (CPKs) are plant proteins that directly bind calcium ions before phosphorylating substrates involved in biotic and abiotic stress responses, as well as development. Arabidopsis thaliana CPK3 (AtCPK3) is involved with plant signaling pathways such as stomatal movement regulation, salt stress response, apoptosis, seed germination and pathogen defense. In this study, AtCPK3 and its orthologues in relatively distant plant species such as rice (Oryza sativa, monocot) and kiwifruit (Actinidia chinensis, asterid eudicot) were analyzed in response to drought, bacteria, fungi, and virus infections. Two orthologues were studied in O. sativa, namely OsCPK1 and OsCPK15, while one orthologue—AcCPK16—was identified in A. chinensis. Reverse-transcriptase quantitative PCR (RT-qPCR) analysis revealed that OsCPK1 and AcCPK16 exhibit similar responses to stressors to AtCPK3. OsCPK15 responded differently, particularly in bacterial and fungal infections. An increase in expression was consistently observed among AtCPK3 and its orthologues in response to virus infection. Overexpression mutants in both Arabidopsis and kiwifruit showed slight tolerance to drought, while knockout mutants were slightly more susceptible or had little difference with wild-type plants. Overexpression mutants in Arabidopsis showed slight tolerance to virus infection. These findings highlight the importance of AtCPK3 and its orthologues in drought and pathogen responses and suggest such function must be conserved in its orthologues in a wide range of plants. Full article