Basal Angiosperms Research Articles

Trioecy in Flowering Plants

Populations of trioecious plants consists of individuals with staminate, pistillate, and hermaphrodite flowers. Trioecy is extremely rare in angiosperms, and relevant data are scarce. A list of trioecious plants found in the global flora was compiled on the basis of literature data and original research. The list includes 80 species of 46 genera, which represent 33 families and 21 orders of flowering plants. Trioecy is found in 7.9% of families, 0.3% of genera, and 0.03% of species in angiosperms. Trioecious species are now unknown in basal angiosperms, uncommon in magnoliids, and rather rare in monocots. The overwhelming majority (87.5%) of trioecious plants belong to Superrosids (30 species) and Superasterids (40 species). The greatest numbers of trioecious species are found in the families Rosaceae (nine species of two genera), Caprifoliaceae (seven species of one genus), Scrophulariaceae (seven species of one genus), Caryophyllaceae (six species of two genera), and Celastraceae (six species of two genera). Almost half of the identified trioecious species represent five genera: Fragaria L. (eight species), Valeriana L. (seven species), Buddleja L. (seven species), Maytenus Molina (five species), and Silene L. (five species). An association with trioecy was analyzed for several biological and ecological factors, such as the life form, the method of pollination, the perianth color, the pericarp consistency, the presence of related dioecious species in the same genus, the latitudinal position, and the distribution through floristic phytochoria. A lability of sex differentiation in certain trioecious plants, the proportion of sex forms in a population, a possible association with polyploidy, and mechanisms of trioecy maintenance and evolution in flowering plants are discussed.

Gene identification and tissue expression analysis inform the floral organization and color in the basal angiosperm Magnolia polytepala (Magnoliaceae).

In Magnolia polytepala, the formation of floral organization and color was attributed to tissue-dependent differential expression levels of MADS-box genes and anthocyanin biosynthetic genes. In angiosperms, the diversity of floral morphology and organization suggests its value in exploring plant evolution. Magnolia polytepala, an endemic basal angiosperm species in China, possesses three green sepal-like tepals in the outermost whorl and pink petal-like tepals in the inner three whorls, forming unique floral morphology and organization. However, we know little about its underlying molecular regulatory mechanism. Here, we first reported the full-length transcriptome of M. polytepala using PacBio sequencing. A total of 16 MADS-box transcripts were obtained from the transcriptome data, including floral homeotic genes (e.g., MpAPETALA3) and other non-floral homeotic genes (MpAGL6, etc.). Phylogenetic analysis and spatial expression pattern reflected their putative biological function as their homologues in Arabidopsis. In addition, nine structural genes involved in anthocyanin biosynthesis pathway had been screened out, and tepal color difference was significantly associated with their tissue-dependent differential expression levels. This study provides a relatively comprehensive investigation of the MADS-box family and anthocyanin biosynthetic genes in M. polytepala, and will facilitate our understanding of the regulatory mechanism underlying floral organization and color in basal angiosperms.

Fossil leaves of Cenomanian basal angiosperms from the Peruc-Korycany Formation, Czechia, central Europe

Two leaf forms are described from the Cenomanian, Late Cretaceous of the Peruc-Korycany Formation in the Bohemian Cretaceous Basin in Central Europe. A new foliage genus and species Ascarinophyllum pecinovense Čepičková et J. Kvaček, gen. et sp. nov. is characterised by serrate margins with rounded chloranthoid teeth bearing a papilla. The leaf is hypostomatic, coriaceous, with resin bodies in the mesophyll. Its venation is festooned semicraspedodromous, with a robust midvein. On the abaxial cuticle, it shows laterocytic/laterocyclocytic, stephanocytic-bicyclic, amphibrachyparacytic, and less frequently brachyparacytic and holoparacytic stomata, showing sometimes T-shaped thickenings of the internal cuticle at the poles. The abaxial cuticle bears external striations; stomata are surrounded by stomatal rims. The leaf is compared to similar Early and Late Cretaceous angiosperm foliage, and to foliage of extant basal angiosperms. Cuticle analysis shows similarities in stomatal construction and external striations of the abaxial cuticle with fossil leaves of Mesodescolea plicata and extant Chloranthaceae.Todziaphyllum saportanum (Velen.) Čepičková et J.Kvaček comb.nov. is revised and its diagnosis is emended. T. saportanum leaf is characterised by serrate margins and semicraspedodromous venation. It is compared to morphologically similar Cretaceous angiosperm foliage, including Ascarinophyllum pecinovense. It is particularly similar to the recently defined fossil leaf Todziaphyllum elongatum, interpreted as having chloranthaceous affinity.

Characterization of the MADS-Box Gene Family in Akebia trifoliata and Their Evolutionary Events in Angiosperms.

As the largest clade of modern plants, flower plants have evolved a wide variety of flowers and fruits. MADS-box genes play key roles in regulating plant morphogenesis, while basal eudicots have an evolutionarily important position of acting as an evolutionary bridge between basal angiosperms and core eudicots. Akebia trifoliata is an important member of the basal eudicot group. To study the early evolution of angiosperms, we identified and characterized the MADS-Box gene family on the whole-genome level of A. trifoliata. There were 47 MADS-box genes (13 type I and 34 type II genes) in the A. trifoliata genome; type I genes had a greater gene length and coefficient of variation and a smaller exon number than type II genes. A total of 27 (57.4%) experienced whole or segmental genome duplication and purifying selection. A transcriptome analysis suggested that three and eight genes were involved in whole fruit and seed development, respectively. The diversification and phylogenetic analysis of 1479 type II MADS-box genes of 22 angiosperm species provided some clues indicating that a γ whole genome triplication event of eudicots possibility experienced a two-step process. These results are valuable for improving A. trifoliata fruit traits and theoretically elucidating evolutionary processes of angiosperms, especially eudicots.

Antibacterial and Antifungal Alkaloids from Asian Angiosperms: Distribution, Mechanisms of Action, Structure-Activity, and Clinical Potentials.

The emergence of multidrug-resistant bacteria and fungi requires the development of antibiotics and antifungal agents. This review identified natural products isolated from Asian angiosperms with antibacterial and/or antifungal activities and analyzed their distribution, molecular weights, solubility, and modes of action. All data in this review were compiled from Google Scholar, PubMed, Science Direct, Web of Science, ChemSpider, PubChem, and a library search from 1979 to 2022. One hundred and forty-one antibacterial and/or antifungal alkaloids were identified during this period, mainly from basal angiosperms. The most active alkaloids are mainly planar, amphiphilic, with a molecular mass between 200 and 400 g/mol, and a polar surface area of about 50 Å2, and target DNA and/or topoisomerase as well as the cytoplasmic membrane. 8-Acetylnorchelerythrine, cryptolepine, 8-hydroxydihydrochelerythrine, 6-methoxydihydrosanguinarine, 2′-nortiliacorinine, pendulamine A and B, rhetsisine, sampangine, tiliacorine, tryptanthrin, tylophorinine, vallesamine, and viroallosecurinine yielded MIC ≤ 1 µg/mL and are candidates for the development of lead molecules.

Deep evaluation of the evolutionary history of the Heat Shock Factor (HSF) gene family and its expansion pattern in seed plants.

Heat shock factor (HSF) genes are essential in some of the basic developmental pathways in plants. Despite extensive studies on the structure, functional diversification, and evolution of HSF genes, their divergence history and gene duplication pattern remain unknown. To further illustrate the probable divergence patterns in these subfamilies, we analyzed the evolutionary history of HSF genes using phylogenetic reconstruction and genomic syntenic analyses, taking advantage of the increased sampling of genomic data from pteridophytes, gymnosperms and basal angiosperms. We identified a novel clade that includes HSFA2, HSFA6, HSFA7, and HSFA9 with a complex relationship, which is very likely due to orthologous or paralogous genes retained after frequent gene duplication events. We hypothesized that HSFA9 derives from HSFA2 through gene duplication in eudicots at the ancestral state, and then expanded in a lineage-specific way. Our findings indicate that HSFB3 and HSFB5 emerged before the divergence of ancestral angiosperms, but were lost in the most recent common ancestors of monocots. We also presumed that HSFC2 derives from HSFC1 in ancestral monocots. This work proposes that during the radiation of flowering plants, an era during which there was a differentiation of angiosperms, the size of the HSF gene family was also being adjusted with considerable sub- or neo-functionalization. The independent evolution of HSFs in eudicots and monocots, including lineage-specific gene duplication, gave rise to a new gene in ancestral eudicots and monocots, and lineage-specific gene loss in ancestral monocots. Our analyses provide essential insights for studying the evolutionary history of this multigene family.

The evolution of diffusive and biochemical capacities for photosynthesis was predominantly shaped by [CO2] with a smaller contribution from [O2

The atmospheric concentration of carbon dioxide ([CO2]) and oxygen ([O2]) directly influence rates of photosynthesis (PN) and photorespiration (RPR) through the enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO). Levels of [CO2] and [O2] have varied over Earth history affecting rates of both CO2 uptake and loss, alongside associated transpirative water-loss. The availability of CO2 has likely acted as a stronger selective pressure than [O2] due to the greater specificity of RubisCO for CO2. The role of [O2], and the interaction of [O2] and [CO2], in plant evolutionary history is less understood. We exposed twelve phylogenetically diverse species to combinations of sub-ambient, ambient and super-ambient [O2] and [CO2] to examine the biochemical and diffusive components of PN and the possible role of [O2] as a selective pressure. Photosynthesis, photosynthetic capacity and stomatal, mesophyll and total conductance to CO2 were higher in the derived eudicot and monocot angiosperms than the more basal ferns, gymnosperms and basal angiosperms which originated in atmospheres characterised by higher CO2:O2 ratios. The ratio of RPR:PN was lower in the monocots, consistent with greater carboxylation capacity and higher stomatal and mesophyll conductance making easier CO2 delivery to chloroplasts. The effect of [O2] and [CO2] on PN/RPR was less evident in more derived species with a higher conductance to CO2. The effect of [O2] was less apparent at high [CO2], suggesting that atmospheric [O2] may only have exerted a strong selective pressure on plant photosynthetic processes during periods characterised by low atmospheric CO2:O2 ratios. Current rising [CO2] will predominantly enhance PN rates in species with low diffusive conductance to CO2.

Genome-Wide Analysis of NBS-LRR Genes From an Early-Diverging Angiosperm Euryale ferox.

NBS-LRR genes are the largest gene family in plants conferring resistance to pathogens. At present, studies on the evolution of NBS-LRR genes in angiosperms mainly focused on monocots and eudicots, while studies on NBS-LRR genes in the basal angiosperms are limited. Euryale ferox represents an early-diverging angiosperm order, Nymphaeales, and confronts various pathogens during its lifetime, which can cause serious economic losses in terms of yield and quality. In this study, we performed a genome-wide identification and analysis of NBS-LRR genes in E. ferox. All 131 identified NBS-LRR genes could be divided into three subclasses according to different domain combinations, including 18 RNLs, 40 CNLs, and 73 TNLs. The E. ferox NBS-LRR genes are unevenly distributed on 29 chromosomes; 87 genes are clustered at 18 multigene loci, and 44 genes are singletons. Gene duplication analysis revealed that segmental duplications acted as a major mechanism for NBS-LRR gene expansions but not for RNL genes, because 18 RNL genes were scattered over 11 chromosomes without synteny loci, indicating that the expansion of RNL genes could have been caused by ectopic duplications. Ancestral gene reconciliation based on phylogenetic analysis revealed that there were at least 122 ancestral NBS-LRR lineages in the common ancestor of the three Nymphaeaceae species, suggesting that NBS-LRR genes expanded slightly during speciation in E. ferox. Transcriptome analysis showed that the majority of NBS-LRR genes were at a low level of expression without pathogen stimulation. Overall, this study characterized the profile of NBS-LRR genes in E. ferox and should serve as a valuable resource for disease resistance breeding in E. ferox.

Modeling basal angiosperm floral phyllotaxis

ABSTRACT : We have developed mathematical models that accurately reproduce the floral meristems of seven angiosperm species from the ANA grade (Amborellales and Austrobaileyales). This allowed us to shed new light on the main problems posed by their phyllotaxis, such as whether it is whorled or spiral (in Nuphar), the origin of organ dédoublement or post-meristematic development.

New Insights into Evolution of the ABC Transporter Family in Mesostigma viride, a Unicellular Charophyte Algae.

ATP-binding cassette (ABC) transporters play an important role in driving the exchange of multiple molecules across cell membranes. The plant ABC transporter family is among the largest protein families, and recent progress has advanced our understanding of ABC classification. However, the ancestral form and deep origin of plant ABCs remain elusive. In this study, we identified 59 ABC transporters in Mesostigma viride, a unicellular charophyte algae that represents the earliest diverging lineage of streptophytes, and 1034 ABCs in genomes representing a broad taxonomic sampling from distantly related plant evolutionary lineages, including chlorophytes, charophytes, bryophytes, lycophytes, gymnosperms, basal angiosperms, monocots, and eudicots. We classified the plant ABC transporters by comprehensive phylogenetic analysis of each subfamily. Our analysis revealed the ancestral type of ABC proteins as well as duplication and gene loss during plant evolution, contributing to our understanding of the functional conservation and diversity of this family. In summary, this study provides new insight into the origin and evolution of plant ABC transporters.

A revised view on the evolution of glutamine synthetase isoenzymes in plants.

SUMMARYGlutamine synthetase (GS) is a key enzyme responsible for the incorporation of inorganic nitrogen in the form of ammonium into the amino acid glutamine. In plants, two groups of functional GS enzymes are found: eubacterial GSIIb (GLN2) and eukaryotic GSIIe (GLN1/GS). Only GLN1/GS genes are found in vascular plants, which suggests that they are involved in the final adaptation of plants to terrestrial life. The present phylogenetic study reclassifies the different GS genes of seed plants into three clusters: GS1a, GS1b and GS2. The presence of genes encoding GS2 has been expanded to Cycadopsida gymnosperms, which suggests the origin of this gene in a common ancestor of Cycadopsida, Ginkgoopsida and angiosperms. GS1a genes have been identified in all gymnosperms, basal angiosperms and some Magnoliidae species. Previous studies in conifers and the gene expression profiles obtained in ginkgo and magnolia in the present work could explain the absence of GS1a in more recent angiosperm species (e.g. monocots and eudicots) as a result of the redundant roles of GS1a and GS2 in photosynthetic cells. Altogether, the results provide a better understanding of the evolution of plant GS isoenzymes and their physiological roles, which is valuable for improving crop nitrogen use efficiency and productivity. This new view of GS evolution in plants, including a new cytosolic GS group (GS1a), has important functional implications in the context of plant metabolism adaptation to global changes.

Evolution and conserved functionality of organ size and shape regulator PEAPOD.

Transcriptional regulator PEAPOD (PPD) and its binding partners comprise a complex that is conserved throughout many core eudicot plants with regard to protein domain sequence and the function of controlling organ size and shape. Orthologues of PPD also exist in the basal angiosperm Amborella trichopoda, various gymnosperm species, the lycophyte Selaginella moellendorffii and several monocot genera, although until now it was not known if these are functional sequences. Here we report constitutive expression of orthologues from species representing diverse taxa of plant phylogeny in the Arabidopsis Δppd mutant. PPD orthologues from S. moellendorffii, gymnosperm Picea abies, A. trichopoda, monocot Musa acuminata, and dicot Trifolium repens were able to complement the mutant and return it to the wild-type phenotype, demonstrating the conserved functionality of PPD throughout vascular plants. In addition, analysis of bryophyte genomes revealed potential PPD orthologues in model liverwort and moss species, suggesting a more primitive lineage for this conserved regulator. The Poaceae (grasses) lack the genes for the PPD module and the reason for loss of the complex from this economically significant family is unclear, given that grasses were the last of the flowering plants to evolve. Bioinformatic analyses identified putative PPD orthologues in close relatives of the Poaceae, indicating that the explanation for absence of PPD in the grasses may be more complex than previously considered. Understanding the mechanisms which led to loss of PPD from the grasses will provide insight into evolution of the Poaceae.

De novo transcriptome assembly reveals three alternative oxidase encoding genes in Nymphaea alba L.

Water lilies are aquatic, ornamental and economically valuable plants classified under Nymphaea genus. Nymphaea alba L., white water lily, has a special focus since it is a member of basal angiosperms. Alternative oxidase (AOX) proteins are the terminal oxidases in the electron transport chain of plants. Identification of alternative oxidase encoding genes for basal angiosperms is important to increase the quality of phylogenetic studies. However, AOX encoding genes were yet to be discovered for N. alba. In this study, we aimed to identify alternative oxidase encoding genes in N. alba by performing transcriptome analysis. Annotation of 272,934 unigenes with Trinotate tool revealed 77 transcripts with AOX domains characterized in known alternative oxidases. Blast analysis of these 77 sequences with known AOX proteins revealed three distinct AOX genes (AOX1, AOX2 and AOX4) in N. alba. After in silico subcellular localization analysis of three identified AOX proteins, AOX1, AOX2 are predicted as mitochondrial while AOX4 is a plastidic alternative oxidase protein. Template-based structural modeling results showed that all identified proteins are statistically similar to known structure models of corresponding AOXs.

Genome-wide identification of the Liriodendron chinense WRKY gene family and its diverse roles in response to multiple abiotic stress

BackgroundLiriodendron chinense (Lchi) is a tree species within the Magnoliaceae family and is considered a basal angiosperm. The too low or high temperature or soil drought will restrict its growth as the adverse environmental conditions, thus improving L. chinense abiotic tolerance was the key issues to study. WRKYs are a major family of plant transcription factors known to often be involved in biotic and abiotic stress responses. So far, it is still largely unknown if and how the LchiWRKY gene family is tied to regulating L. chinense stress responses. Therefore, studying the involvement of the WRKY gene family in abiotic stress regulation in L. chinense could be very informative in showing how this tree deals with such stressful conditions.ResultsIn this research, we performed a genome-wide analysis of the Liriodendron chinense (Lchi) WRKY gene family, studying their classification relationships, gene structure, chromosomal locations, gene duplication, cis-element, and response to abiotic stress. The 44 members of the LchiWRKY gene family contain a significant amount of sequence diversity, with their lengths ranging from 525 bp to 40,981 bp. Using classification analysis, we divided the 44 LchiWRKY genes into three phylogenetic groups (I, II, II), with group II then being further divided into five subgroups (IIa, IIb, IIc, IId, IIe). Comparative phylogenetic analysis including the WRKY families from 17 plant species suggested that LchiWRKYs are closely related to the Magnolia Cinnamomum kanehirae WRKY family, and has fewer family members than higher plants. We found the LchiWRKYs to be evenly distributed across 15 chromosomes, with their duplication events suggesting that tandem duplication may have played a major role in LchiWRKY gene expansion model. A Ka/Ks analysis indicated that they mainly underwent purifying selection and distributed in the group IId. Motif analysis showed that LchiWRKYs contained 20 motifs, and different phylogenetic groups contained conserved motif. Gene ontology (GO) analysis showed that LchiWRKYs were mainly enriched in two categories, i.e., biological process and molecular function. Two group IIc members (LchiWRKY10 and LchiWRKY37) contain unique WRKY element sequence variants (WRKYGKK and WRKYGKS). Gene structure analysis showed that most LchiWRKYs possess 3 exons and two different types of introns: the R- and V-type which are both contained within the WRKY domain (WD). Additional promoter cis-element analysis indicated that 12 cis-elements that play different functions in environmental adaptability occur across all LchiWRKY groups. Heat, cold, and drought stress mainly induced the expression of group II and I LchiWRKYs, some of which had undergone gene duplication during evolution, and more than half of which had three exons. LchiWRKY33 mainly responded to cold stress and LchiWRKY25 mainly responded to heat stress, and LchiWRKY18 mainly responded to drought stress, which was almost 4-fold highly expressed, while 5 LchiWRKYs (LchiWRKY5, LchiWRKY23, LchiWRKY14, LchiWRKY27, and LchiWRKY36) responded equally three stresses with more than 6-fold expression. Subcellular localization analysis showed that all LchiWRKYs were localized in the nucleus, and subcellular localization experiments of LchiWRKY18 and 36 also showed that these two transcription factors were expressed in the nucleus.ConclusionsThis study shows that in Liriodendron chinense, several WRKY genes like LchiWRKY33, LchiWRKY25, and LchiWRKY18, respond to cold or heat or drought stress, suggesting that they may indeed play a role in regulating the tree’s response to such conditions. This information will prove a pivotal role in directing further studies on the function of the LchiWRKY gene family in abiotic stress response and provides a theoretical basis for popularizing afforestation in different regions of China.

Systematic-taxonomic revision of the flora from the late Oligocene Fossillagerstätte Rott near Bonn (Germany). Part 2: Magnoliidae: Basal angiosperms and magnoliids

Systematic-taxonomic revision of the flora from the late Oligocene Fossillagerstätte Rott near Bonn (Germany). Part 2: Magnoliidae: Basal angiosperms and magnoliids

MtNPF6.5 mediates chloride uptake and nitrate preference in Medicago roots.

The preference for nitrate over chloride through regulation of transporters is a fundamental feature of plant ion homeostasis. We show that Medicago truncatula MtNPF6.5, an ortholog of Arabidopsis thaliana AtNPF6.3/NRT1.1, can mediate nitrate and chloride uptake in Xenopus oocytes but is chloride selective and that its close homologue, MtNPF6.7, can transport nitrate and chloride but is nitrate selective. The MtNPF6.5 mutant showed greatly reduced chloride content relative to wild type, and MtNPF6.5 expression was repressed by high chloride, indicating a primary role for MtNPF6.5 in root chloride uptake. MtNPF6.5 and MtNPF6.7 were repressed and induced by nitrate, respectively, and these responses required the transcription factor MtNLP1. Moreover, loss of MtNLP1 prevented the rapid switch from chloride to nitrate as the main anion in nitrate-starved plants after nitrate provision, providing insight into the underlying mechanism for nitrate preference. Sequence analysis revealed three sub-types of AtNPF6.3 orthologs based on their predicted substrate-binding residues: A (chloride selective), B (nitrate selective), and C (legume specific). The absence of B-type AtNPF6.3 homologues in early diverged plant lineages suggests that they evolved from a chloride-selective MtNPF6.5-like protein.

Organelle Genomes and Transcriptomes of Nymphaea Reveal the Interplay between Intron Splicing and RNA Editing.

Posttranscriptional modifications, including intron splicing and RNA editing, are common processes during regulation of gene expression in plant organelle genomes. However, the intermediate products of intron-splicing, and the interplay between intron-splicing and RNA-editing were not well studied. Most organelle transcriptome analyses were based on the Illumina short reads which were unable to capture the full spectrum of transcript intermediates within an organelle. To fully investigate the intermediates during intron splicing and the underlying relationships with RNA editing, we used PacBio DNA-seq and Iso-seq, together with Illumina short reads genome and transcriptome sequencing data to assemble the chloroplast and mitochondrial genomes of Nymphaea ‘Joey Tomocik’ and analyze their posttranscriptional features. With the direct evidence from Iso-seq, multiple intermediates partially or fully intron-spliced were observed, and we also found that both cis- and trans-splicing introns were spliced randomly. Moreover, by using rRNA-depleted and non-Oligo(dT)-enrichment strand-specific RNA-seq data and combining direct SNP-calling and transcript-mapping methods, we identified 98 and 865 RNA-editing sites in the plastome and mitogenome of N. ‘Joey Tomocik’, respectively. The target codon preference, the tendency of increasing protein hydrophobicity, and the bias distribution of editing sites are similar in both organelles, suggesting their common evolutionary origin and shared editing machinery. The distribution of RNA editing sites also implies that the RNA editing sites in the intron and exon regions may splice synchronously, except those exonic sites adjacent to intron which could only be edited after being intron-spliced. Our study provides solid evidence for the multiple intermediates co-existing during intron-splicing and their interplay with RNA editing in organelle genomes of a basal angiosperm.

Phylogeny and subcellular localization analyses reveal distinctions in monocot and eudicot class IV acyl-CoA-binding proteins.

Plant class IV ACBPs diverged with the split of monocots and eudicots. Difference in the subcellular localization supported the functional variation of plant class IV ACBP. Acyl-CoA-binding proteins (ACBPs) are divided into class I-IV in plants. Class IV ACBPs are kelch motif containing proteins that are specific to plants. The currently known subcellular localizations of plant class IV ACBPs are either in the cytosol (Arabidopsis) or in the peroxisomes (rice). However, it is not clear whether peroxisomal localization of class IV ACBP is a shared character that distinguishes eudicots and monocots. Here, the phylogeny of class IV ACBPs from 73 plant species and subcellular localization of class IV ACBPs from six monocots and eudicots were conducted. Phylogenetic analysis of 112 orthologues revealed that monocot class IV ACBPs were basal to the monophyletic clade formed by eudicots and basal angiosperm. Transient expression of GFP fusions in onion epidermal cells demonstrated that monocot maize (Zea mays), wheat (Triticum aestivum), and sorghum (Sorghum bicolor) and eudicot poplar (Populus trichocarpa) all contained at least one peroxisomal localized class IV ACBP, while orthologues from cucumber (Cucumis sativus L.) and soybean (Glycine max) were all cytosolic. Combining the location of Arabidopsis and rice class IV ACBPs, it indicates that maintaining at least one peroxisomal class IV ACBP could be a shared feature within the tested monocots, while cytosolic class IV ACBPs would be preferred in the tested eudicots. Furthermore, the interaction between OsACBP6 and peroxisomal ATP-binding cassette (ABC) transporter provided clues for the functional mechanism of OsACBP6.

Predicting potential medicinal plants with phylogenetic topology: Inspiration from the research of traditional Chinese medicine

Ethnopharmacological relevancePlants are a dominant source of pharmacological drugs for the treatment and cure of different disorders and diseases. However, selecting the most biologically active plant species for further screening is still challenging. Phylogeny has strong explanatory powers and provides predictive perspectives that are not available in traditional plant classifications. China, which is endowed with a diverse set of therapeutic cures from Mother Nature, represents an ideal environment for the phylogenetic analysis of potential medicinal plants. Materials and methodsHerein, we prepared a database of 7,451 traditional Chinese medicinal (TCM) plants, including species with therapeutic effects grouped in 14 categories. To limit our exploration of novel therapeutic species, we plotted the medicinal effects on the phylogenetic tree of almost 30,000 species of China to find hot nodes of therapeutic effects. We used the net relatedness index (NRI) and the nearest taxon index (NTI) to identify clustering and overdispersion of the phylogenetic distribution of TCM plants. ResultsThe NRI and NTI analyses highlighted 3,392 hot node species with single therapeutic effects within 507 genera and 89 families on the phylogenetic tree and about 70% of the 14 medicinal categories clusters identified. The general pattern of the hot nodes on the phylogenetic tree indicates that basal angiosperms and basal eudicots radiated for therapeutic effects. ConclusionsOur study may provide a more targeted way to discover phylogeny-guided drugs in the early screening stage, which may lead to a higher discovery efficiency of new drugs with meaningful biological activities. Phylogenetic studies of plants that are richer in bioactive compounds can set the ground for the identification and discovery of alternative drugs.

Gas exchange and hydraulic function in seedlings of three basal angiosperm tree-species during water-withholding and re-watering

Basal angiosperms have relatively primitive hydraulic systems and may be vulnerable to drought. The coordination in hydraulic function between leaf, stem and root of a plant during and after a drought is not well understood. Here, we examined the interaction between gas exchange and hydraulic function in the leaves, stems, and intact root systems of potted-seedlings of three evergreen basal angiosperm tree-species exposed to a cycle of severe water stress and subsequent rewatering. In all three species, stomatal closure occurred at water potentials before 50% loss of stem hydraulic conductivity, because their leaves and roots were more vulnerable to drought than the stems. Manglietia insignis that has scalariform perforatiom plates was more vulnerable to drought than the other two species that have simple porforation plates. During rewatering, water potentials of D. chinensis and C. camphora were recovered after 10 days, their gas exchange were gradually recovered and reached to pre-drought levels after 3 weeks, whereas, the recovery of hydraulic function in their leaves, stems and roots lagged behind but also reached pre-drought levels after 3 weeks. Manglietia insignis displayed poor recovery in both gas exchange and hydraulic function and a high mortality. Our results reveal that drought-induced severe embolism can be recovered even in seedlings of basal angiosperms depending on species if a drought does not persist long, and earlier recovery in xylem water potential and gas exchange than hydraulic function.