Genomic Features and Phylogenetic Analysis of Antimicrobial-Resistant Salmonella Mbandaka ST413 Strains.

In recent years, Salmonella enterica subsp. enterica serovar Mbandaka (S. Mbandaka) has been increasingly isolated from laying hens and shell eggs around the world. Moreover, this serovar has been identified as the causative agent of several salmonellosis outbreaks in humans. Surprisingly, little is known about the characteristics of this emerging serovar, and therefore, we investigated antimicrobial resistance, virulence, and prophage genes of six selected Brazilian strains of Salmonella Mbandaka using Whole Genome Sequencing (WGS). Multi-locus sequence typing revealed that the tested strains belong to Sequence Type 413 (ST413), which has been linked to recent multi-country salmonellosis outbreaks in Europe. A total of nine resistance genes were detected, and the most frequent ones were aac(6')-Iaa, sul1, qacE, blaOXA-129, tet(B), and aadA1. A point mutation in ParC at the 57th position (threonine → serine) associated with quinolone resistance was present in all investigated genomes. A 112,960 bp IncHI2A plasmid was mapped in 4/6 strains. This plasmid harboured tetracycline (tetACDR) and mercury (mer) resistance genes, genes contributing to conjugative transfer, and genes involved in plasmid maintenance. Most strains (four/six) carried Salmonella genomic island 1 (SGI1). All S. Mbandaka genomes carried seven pathogenicity islands (SPIs) involved in intracellular survival and virulence: SPIs 1-5, 9, and C63PI. The virulence genes csgC, fimY, tcfA, sscA, (two/six), and ssaS (one/six) were absent in some of the genomes; conversely, fimA, prgH, and mgtC were present in all of them. Five Salmonella bacteriophage sequences (with homology to Escherichia phage phiV10, Enterobacteria phage Fels-2, Enterobacteria phage HK542, Enterobacteria phage ST64T, Salmonella phage SW9) were identified, with protein counts between 31 and 54, genome lengths of 24.7 bp and 47.7 bp, and average GC content of 51.25%. In the phylogenetic analysis, the genomes of strains isolated from poultry in Brazil clustered into well-supported clades with a heterogeneous distribution, primarily associated with strains isolated from humans and food. The phylogenetic relationship of Brazilian S. Mbandaka suggests the presence of strains with high epidemiological significance and the potential to be linked to foodborne outbreaks. Overall, our results show that isolated strains of S. Mbandaka are multidrug-resistant and encode a rather conserved virulence machinery, which is an epidemiological hallmark of Salmonella strains that have successfully disseminated both regionally and globally.

Phylogenetical Position versus Pollination Syndromes: Floral Trichomes of Central American and Mexican Pinguicula.

Central American and Mexican Pinguicula species are characterized by enormous divergence in size and color of flowers and are pollinated by butterflies, flies, bees, and hummingbirds. It is known that floral trichomes are key characters in plant-pollinator interaction. The main aim of our study was to verify our hypothesis that the distribution and diversity of non-glandular and glandular trichomes are related to the pollinator syndromes rather than the phylogenetic relationships. The studied sample consisted of Central American and Mexican species. In our study, we relied on light microscopy and scanning electron microscopy with a phylogenetic perspective based on ITS DNA sequences. The flower morphology of species pollinated by butterflies and hummingbirds was similar in contrast to species pollinated by flies and bees. Species pollinated by butterflies and hummingbirds contained low diversity of non-glandular trichomes, which occurred mostly in the tube and basal part of the spur. Surprisingly, in P. esseriana and P. mesophytica, non-glandular trichomes also occurred at the base of lower lip petals. In the case of species pollinated by flies/bees, we observed a high variety of non-glandular trichomes, which occurred on the surface of corolla petals, in the tube, and at the entrance to the spur. Furthermore, we did not identify any non-glandular trichomes in the spur. The capitate glandular trichomes were of similar morphology in all examined species. There were minor differences in the shape of the trichome head, as well as the length and the number of stalk cells. The distribution and the diversity of non-glandular and glandular trichomes and pollinator syndromes were mapped onto a phylogenetic reconstruction of the genus. Most micromorphological characters appear to be associated more with floral adaptation to pollinators and less with phylogeny.

The phylogenomics and evolutionary dynamics of the organellar genomes in carnivorous Utricularia and Genlisea species (Lentibulariaceae).

Utricularia and Genlisea are highly specialized carnivorous plants whose phylogenetic history has been poorly explored using phylogenomic methods. Additional sampling and genomic data are needed to advance our phylogenetic and taxonomic knowledge of this group of plants. Within a comparative framework, we present a characterization of plastome (PT) and mitochondrial (MT) genes of 26 Utricularia and six Genlisea species, with representatives of all subgenera and growth habits. All PT genomes maintain similar gene content, showing minor variation across the genes located between the PT junctions. One exception is a major variation related to different patterns in the presence and absence of ndh genes in the small single copy region, which appears to follow the phylogenetic history of the species rather than their lifestyle. All MT genomes exhibit similar gene content, with most differences related to a lineage-specific pseudogenes. We find evidence for episodic positive diversifying selection in PT and for most of the Utricularia MT genes that may be related to the current hypothesis that bladderworts' nuclear DNA is under constant ROS oxidative DNA damage and unusual DNA repair mechanisms, or even low fidelity polymerase that bypass lesions which could also be affecting the organellar genomes. Finally, both PT and MT phylogenetic trees were well resolved and highly supported, providing a congruent phylogenomic hypothesis for Utricularia and Genlisea clade given the study sampling.

Comparative analyses of Theobroma cacao and T. grandiflorum mitogenomes reveal conserved gene content embedded within complex and plastic structures.

Unlike the chloroplast genomes (ptDNA), the plant mitochondrial genomes (mtDNA) are much more plastic in structure and size but maintain a conserved and essential gene set related to oxidative phosphorylation. Moreover, the plant mitochondrial genes and mtDNA are good markers for phylogenetic, evolutive, and comparative analyses. The two most known species in Theobroma L. (Malvaceae s.l.) genus are T. cacao, and T. grandiflorum. Besides the economic value, both species also show considerable biotechnology potential due to their other derived products, thus, aggregating additional economic value for the agroindustry. Here, we assembled and compared the mtDNA of Theobroma cacao and T. grandiflorum to generate a new genomics resource and unravel evolutionary trends. Graph-based analyses revealed that both mtDNA exhibit multiple alternative arrangements, confirming the dynamism commonly observed in plant mtDNA. The disentangled assembly graph revealed potential predominant circular molecules. The master circle molecules span 543,794 bp for T. cacao and 501,598 bp for T. grandiflorum, showing 98.9% of average sequence identity. Both mtDNA contains the same set of 39 plant mitochondrial genes, commonly found in other rosid mitogenomes. The main features are a duplicated copy of atp4, the absence of rpl6, rps2, rps8, and rps11, and the presence of two chimeric open-reading frames. Moreover, we detected few ptDNA integrations mainly represented by tRNAs, and no viral sequences were detected. Phylogenomics analyses indicate Theobroma spp. are nested in Malvaceae family. The main mtDNA differences are related to distinct structural rearrangements and exclusive regions associated with relics of Transposable Elements, supporting the hypothesis of dynamic mitochondrial genome maintenance and divergent evolutionary paths and pressures after species differentiation.

The complete organellar genomes of the entheogenic plant Psychotria viridis (Rubiaceae), a main component of the ayahuasca brew.

Psychotria viridis (Rubioideae: Rubiaceae), popularly known as chacrona, is commonly found as a shrub in the Amazon region and is well-known to produce psychoactive compounds, such as the N,N-dimethyltryptamine (DMT). Together with the liana Banisteropsis caapi, P. viridis is one of the main components of the Amerindian traditional, entheogenic beverage known as ayahuasca. In this work, we assembled and annotated the organellar genomes (ptDNA and mtDNA), presenting the first genomics resources for this species. The P. viridis ptDNA exhibits 154,106 bp, encoding all known ptDNA gene repertoire found in angiosperms. The Psychotria genus is a complex paraphyletic group, and according to phylogenomic analyses, P. viridis is nested in the Psychotrieae clade. Comparative ptDNA analyses indicate that most Rubiaceae plastomes present conserved ptDNA structures, often showing slight differences at the junction sites of the major four regions (LSC-IR-SSC). For the mitochondrion, assembly graph-based analysis supports a complex mtDNA organization, presenting at least two alternative and circular mitogenomes structures exhibiting two main repeats spanning 24 kb and 749 bp that may symmetrically isomerize the mitogenome into variable arrangements and isoforms. The circular mtDNA sequences (615,370 and 570,344 bp) encode almost all plant mitochondrial genes (except for the ccmC, rps7, rps10, rps14, rps19, rpl2 and rpl16 that appears as pseudogenes, and the absent genes sdh3, rps2, rsp4, rsp8, rps11, rpl6, and rpl10), showing slight variations related to exclusive regions, ptDNA integration, and relics of previous events of LTR-RT integration. The detection of two mitogenomes haplotypes is evidence of heteroplasmy as observed by the complex organization of the mitochondrial genome using graph-based analysis. Taken together, these results elicit the primary insights into the genome biology and evolutionary history of Psychotria viridis and may be used to aid strategies for conservation of this sacred, entheogenic species.

Immunocytochemical Analysis of the Wall Ingrowths in the Digestive Gland Transfer Cells in Aldrovanda vesiculosa L. (Droseraceae).

Carnivorous plants are unique due to their ability to attract small animals or protozoa, retain them in specialized traps, digest them, and absorb nutrients from the dissolved prey material; however, to this end, these plants need a special secretion-digestive system (glands). A common trait of the digestive glands of carnivorous plants is the presence of transfer cells. Using the aquatic carnivorous species Aldrovanda vesiculosa, we showed carnivorous plants as a model for studies of wall ingrowths/transfer cells. We addressed the following questions: Is the cell wall ingrowth composition the same between carnivorous plant glands and other plant system models? Is there a difference in the cell wall ingrowth composition between various types of gland cells (glandular versus endodermoid cells)? Fluorescence microscopy and immunogold electron microscopy were employed to localize carbohydrate epitopes associated with major cell wall polysaccharides and glycoproteins. The cell wall ingrowths were enriched with arabinogalactan proteins (AGPs) localized with the JIM8, JIM13, and JIM14 epitopes. Both methylesterified and de-esterified homogalacturonans (HGs) were absent or weakly present in the wall ingrowths in transfer cells (stalk cells and head cells of the gland). Both the cell walls and the cell wall ingrowths in the transfer cells were rich in hemicelluloses: xyloglucan (LM15) and galactoxyloglucan (LM25). There were differences in the composition between the cell wall ingrowths and the primary cell walls in A. vesiculosa secretory gland cells in the case of the absence or inaccessibility of pectins (JIM5, LM19, JIM7, LM5, LM6 epitopes); thus, the wall ingrowths are specific cell wall microdomains. Even in the same organ (gland), transfer cells may differ in the composition of the cell wall ingrowths (glandular versus endodermoid cells). We found both similarities and differences in the composition of the cell wall ingrowths between the A. vesiculosa transfer cells and transfer cells of other plant species.

The complete mitochondrial genome of carnivorous Genlisea tuberosa (Lentibulariaceae): Structure and evolutionary aspects.

Sequenced genomic data for carnivorous plants are scarce, especially regarding the mitogenomes (MTs) and further studies are crucial to obtain a better understanding of the topic. In this study, we sequenced and characterized the mitochondrial genome of the tuberous carnivorous plant Genlisea tuberosa, being the first of its genus to be sequenced. The genome comprises 729,765 bp, encoding 80 identified genes of which 36 are protein-coding, 40 tRNA, four rRNA genes, and three pseudogenes. An intronic region from the cox1 gene was identified that encodes an endonuclease enzyme that is present in the other sequenced species of Lentibulariaceae. Chloroplast genes (pseudogene and complete) inserted in the MT genome were identified, showing possible horizontal transfer between organelles. In addition, 50 pairs of long repeats from 94 to 274 bp are present, possibly playing an important role in the maintenance of the MT genome. Phylogenetic analysis carried out with 34 coding mitochondrial genes corroborated the positioning of the species listed here within the family. The molecular dynamism in the mitogenome (e.g. the loss or pseudogenization of genes, insertion of foreign genes, the long repeats as well as accumulated mutations) may be reflections of the carnivorous lifestyle where a significant part of cellular energy was shifted for the adaptation of leaves into traps molding the mitochondrial DNA. The sequence and annotation of G. tuberosa's MT will be useful for further studies and serve as a model for evolutionary and taxonomic clarifications of the group as well as improving our comprehension of MT evolution.

A Historical Perspective of Bladderworts (Utricularia): Traps, Carnivory and Body Architecture.

The genus Utricularia includes around 250 species of carnivorous plants, commonly known as bladderworts. The generic name Utricularia was coined by Carolus Linnaeus in reference to the carnivorous organs (Utriculus in Latin) present in all species of the genus. Since the formal proposition by Linnaeus, many species of Utricularia were described, but only scarce information about the biology for most species is known. All Utricularia species are herbs with vegetative organs that do not follow traditional models of morphological classification. Since the formal description of Utricularia in the 18th century, the trap function has intrigued naturalists. Historically, the traps were regarded as floating organs, a common hypothesis that was maintained by different botanists. However, Charles Darwin was most likely the first naturalist to refute this idea, since even with the removal of all traps, the plants continued to float. More recently, due mainly to methodological advances, detailed studies on the trap function and mechanisms could be investigated. This review shows a historical perspective on Utricularia studies which focuses on the traps and body organization.

Spatio-Temporal Distribution of Cell Wall Components in the Placentas, Ovules and Female Gametophytes of Utricularia during Pollination.

In most angiosperms, the female gametophyte is hidden in the mother tissues and the pollen tube enters the ovule via a micropylar canal. The mother tissues play an essential role in the pollen tube guidance. However, in Utricularia, the female gametophyte surpasses the entire micropylar canal and extends beyond the limit of the integument. The female gametophyte then invades the placenta and a part of the central cell has direct contact with the ovary chamber. To date, information about the role of the placenta and integument in pollen tube guidance in Utricularia, which have extra-ovular female gametophytes, has been lacking. The aim of this study was to evaluate the role of the placenta, central cell and integument in pollen tube pollen tube guidance in Utricularia nelumbifolia Gardner and Utricularia humboldtii R.H. Schomb. by studying the production of arabinogalactan proteins. It was also determined whether the production of the arabinogalactan proteins is dependent on pollination in Utricularia. In both of the examined species, arabinogalactan proteins (AGPs) were observed in the placenta (epidermis and nutritive tissue), ovule (integument, chalaza), and female gametophyte of both pollinated and unpollinated flowers, which means that the production of AGPs is independent of pollination; however, the production of some AGPs was lower after fertilization. There were some differences in the production of AGPs between the examined species. The occurrence of AGPs in the placental epidermis and nutritive tissue suggests that they function as an obturator. The production of some AGPs in the ovular tissues (nucellus, integument) was independent of the presence of a mature embryo sac.

A Chemometry of Aldrovanda vesiculosa L. (Waterwheel, Droseraceae) Populations.

The genus Aldrovanda is a Palaeogene element containing a single extant species, Aldrovanda vesiculosa L. This aquatic carnivorous herb has a very wide range of distribution, natively covering four continents; however, it is a critically endangered aquatic plant species worldwide. Previous studies revealed that A. vesiculosa had an extremely low genetic variation. The main aim of the present paper is to explore, using chemometric tools, the diversity of 16 A. vesiculosa populations from various sites from four continents (Eurasia, Africa, Australia). Using chemometric data as markers for genetic diversity, we show the relationships of 16 A. vesiculosa populations from various sites, including four continents. Phytochemical markers allowed the identification of five well-supported (bootstrap > 90%) groups among the 16 populations sampled. The principal component analysis data support the idea that the strongly related African (Botswana) and Australian (Kimberley, NT, NW Australia) populations are the most distant ones, separated from the European and Asian ones. However, considering the five Australian populations sampled, three are nested within the Eurasian group. The chemometric data are correlated positively with the geographical distances between the samples, which suggests a tendency toward isolation for the most distant populations.

Structural Features of Carnivorous Plant (Genlisea, Utricularia) Tubers as Abiotic Stress Resistance Organs.

Carnivorous plants from the Lentibulariaceae form a variety of standard and novel vegetative organs and survive unfavorable environmental conditions. Within Genlisea, only G. tuberosa, from the Brazilian Cerrado, formed tubers, while Utricularia menziesii is the only member of the genus to form seasonally dormant tubers. We aimed to examine and compare the tuber structure of two taxonomically and phylogenetically divergent terrestrial carnivorous plants: Genlisea tuberosa and Utricularia menziesii. Additionally, we analyzed tubers of U. mannii. We constructed phylogenetic trees using chloroplast genes matK/trnK and rbcL and used studied characters for ancestral state reconstruction. All examined species contained mainly starch as histologically observable reserves. The ancestral state reconstruction showed that specialized organs such as turions evolved once and tubers at least 12 times from stolons in Lentibulariaceae. Different from other clades, tubers probably evolved from thick stolons for sect. Orchidioides and both structures are primarily water storage structures. In contrast to species from section Orchidioides, G. tuberosa, U. menziesii and U. mannii form starchy tubers. In G. tuberosa and U. menziesii, underground tubers provide a perennating bud bank that protects the species in their fire-prone and seasonally desiccating environments.

Life in the Current: Anatomy and Morphology of Utricularia neottioides.

Rheophytism is extremely rare in the Utricularia genus (there are four strictly rheophytic species out of a total of about 260). Utricularia neottioides is an aquatic rheophytic species exclusively growing attached to bedrocks in the South American streams. Utricularia neottioides was considered to be trap-free by some authors, suggesting that it had given up carnivory due to its specific habitat. Our aim was to compare the anatomy of rheophytic U. neottioides with an aquatic Utricularia species with a typical linear monomorphic shoot from the section Utricularia, U. reflexa, which grows in standing or very slowly streaming African waters. Additionally, we compared the immunodetection of cell wall components of both species. Light microscopy, histochemistry, scanning, and transmission electron microscopy were used to address our aims. In U. neottioides, two organ systems can be distinguished: organs (stolons, inflorescence stalk) which possess sclerenchyma and are thus resistant to water currents, and organs without sclerenchyma (leaf-like shoots), which are submissive to the water streaming/movement. Due to life in the turbulent habitat, U. neottioides evolved specific characters including an anchor system with stolons, which have asymmetric structures, sclerenchyma and they form adhesive trichomes on the ventral side. This anchor stolon system performs additional multiple functions including photosynthesis, nutrient storage, vegetative reproduction. In contrast with typical aquatic Utricularia species from the section Utricularia growing in standing waters, U. neottioides stems have a well-developed sclerenchyma system lacking large gas spaces. Plants produce numerous traps, so they should still be treated as a fully carnivorous plant.

Do food trichomes occur in Pinguicula (Lentibulariaceae) flowers?

BACKGROUND AND AIMS: Floral food bodies (including edible trichomes) are a form of floral reward for pollinators. This type of nutritive reward has been recorded in several angiosperm families: Annonaceae, Araceae, Calycanthaceae, Eupomatiaceae, Himantandraceae, Nymphaeaceae, Orchidaceae, Pandanaceae and Winteraceae. Although these bodies are very diverse in their structure, their cells contain food material: starch grains, protein bodies or lipid droplets. In Pinguicula flowers, there are numerous multicellular clavate trichomes. Previous authors have proposed that these trichomes in the Pinguicula flower play the role of 'futterhaare' ('feeding hairs') and are eaten by pollinators. The main aim of this study was to investigate whether the floral non-glandular trichomes of Pinguicula contain food reserves and thus are a reward for pollinators. The trichomes from the Pinguicula groups, which differ in their taxonomy (species from the subgenera: Temnoceras, Pinguicula and Isoloba) as well as the types of their pollinators (butterflies/flies and bees/hummingbirds), were examined. Thus, it was determined whether there are any connections between the occurrence of food trichomes and phylogeny position or pollination biology. Additionally, we determined the phylogenetic history of edible trichomes and pollinator evolution in the Pinguicula species. METHODS: The species that were sampled were: Pinguicula moctezumae, P. esseriana, P. moranensis, P. emarginata, P. rectifolia, P. mesophytica, P. hemiepiphytica, P. agnata, P. albida, P. ibarrae, P. martinezii, P. filifolia, P. gigantea, P. lusitanica, P. alpina and P. vulgaris. Light microscopy, histochemistry, and scanning and transmission electron microscopy were used to address our aims with a phylogenetic perspective based on matK/trnK DNA sequences. KEY RESULTS: No accumulation of protein bodies or lipid droplets was recorded in the floral non-glandular trichomes of any of the analysed species. Starch grains occurred in the cells of the trichomes of the bee-/fly-pollinated species: P. agnata, P. albida, P. ibarrae, P. martinezii, P. filifolia and P. gigantea, but not in P. alpina or P. vulgaris. Moreover, starch grains were not recorded in the cells of the trichomes of the Pinguicula species that have long spurs, which are pollinated by Lepidoptera (P. moctezumae, P. esseriana, P. moranensis, P. emarginata and P. rectifolia) or birds (P. mesophytica and P. hemiepihytica), or in species with a small and whitish corolla that self-pollinate (P. lusitanica). The results on the occurrence of edible trichomes and pollinator syndromes were mapped onto a phylogenetic reconstruction of the genus. CONCLUSION: Floral non-glandular trichomes play the role of edible trichomes in some Pinguicula species (P. agnata, P. albida, P. ibarrae, P. martinezii, P. filifolia and P. gigantea), which are mainly classified as bee-pollinated species that had originated from Central and South America. It seems that in the Pinguicula that are pollinated by other pollinator groups (Lepidoptera and hummingbirds), the non-glandular trichomes in the flowers play a role other than that of a floral reward for their pollinators. Edible trichomes are symplesiomorphic for the Pinguicula species, and thus do not support a monophyletic group such as a synapomorphy. Nevertheless, edible trichomes are derived and are possibly a specialization for fly and bee pollinators by acting as a food reward for these visitors.

Flower nectar trichome structure of carnivorous plants from the genus butterworts Pinguicula L. (Lentibulariaceae).

Pinguicula (Lentibulariaceae) is a genus comprising around 96 species of herbaceous, carnivorous plants, which are extremely diverse in flower size, colour and spur length and structure as well as pollination strategy. In Pinguicula, nectar is formed in the flower spur; however, there is a gap in the knowledge about the nectary trichome structure in this genus. Our aim was to compare the nectary trichome structure of various Pinguicula species in order to determine whether there are any differences among the species in this genus. The taxa that were sampled were Pinguicula moctezumae, P. moranensis, P. rectifolia, P. emarginata and P. esseriana. We used light microscopy, histochemistry, scanning and transmission electron microscopy to address those aims. We show a conservative nectary trichome structure and spur anatomy in various Mexican Pinguicula species. The gross structural similarities between the examined species were the spur anatomy, the occurrence of papillae, the architecture of the nectary trichomes and the ultrastructure characters of the trichome cells. However, there were some differences in the spur length, the size of spur trichomes, the occurrence of starch grains in the spur parenchyma and the occurrence of cell wall ingrowths in the terminal cells of the nectary trichomes. Similar nectary capitate trichomes, as are described here, were recorded in the spurs of species from other Lentibulariaceae genera. There are many ultrastructural similarities between the cells of nectary trichomes in Pinguicula and Utricularia.

Intraspecific Variation within the Utricularia amethystina Species Morphotypes Based on Chloroplast Genomes.

Utricularia amethystina Salzm. ex A.St.-Hil. & Girard (Lentibulariaceae) is a highly polymorphic carnivorous plant taxonomically rearranged many times throughout history. Herein, the complete chloroplast genomes (cpDNA) of three U. amethystina morphotypes: purple-, white-, and yellow-flowered, were sequenced, compared, and putative markers for systematic, populations, and evolutionary studies were uncovered. In addition, RNA-Seq and RNA-editing analysis were employed for functional cpDNA evaluation. The cpDNA of three U. amethystina morphotypes exhibits typical quadripartite structure. Fine-grained sequence comparison revealed a high degree of intraspecific genetic variability in all morphotypes, including an exclusive inversion in the psbM and petN genes in U. amethystina yellow. Phylogenetic analyses indicate that U. amethystina morphotypes are monophyletic. Furthermore, in contrast to the terrestrial Utricularia reniformis cpDNA, the U. amethystina morphotypes retain all the plastid NAD(P)H-dehydrogenase (ndh) complex genes. This observation supports the hypothesis that the ndhs in terrestrial Utricularia were independently lost and regained, also suggesting that different habitats (aquatic and terrestrial) are not related to the absence of Utricularia ndhs gene repertoire as previously assumed. Moreover, RNA-Seq analyses recovered similar patterns, including nonsynonymous RNA-editing sites (e.g., rps14 and petB). Collectively, our results bring new insights into the chloroplast genome architecture and evolution of the photosynthesis machinery in the Lentibulariaceae.

The Terrestrial Carnivorous Plant Utricularia reniformis Sheds Light on Environmental and Life-Form Genome Plasticity.

Utricularia belongs to Lentibulariaceae, a widespread family of carnivorous plants that possess ultra-small and highly dynamic nuclear genomes. It has been shown that the Lentibulariaceae genomes have been shaped by transposable elements expansion and loss, and multiple rounds of whole-genome duplications (WGD), making the family a platform for evolutionary and comparative genomics studies. To explore the evolution of Utricularia, we estimated the chromosome number and genome size, as well as sequenced the terrestrial bladderwort Utricularia reniformis (2n = 40, 1C = 317.1-Mpb). Here, we report a high quality 304 Mb draft genome, with a scaffold NG50 of 466-Kb, a BUSCO completeness of 87.8%, and 42,582 predicted genes. Compared to the smaller and aquatic U. gibba genome (101 Mb) that has a 32% repetitive sequence, the U. reniformis genome is highly repetitive (56%). The structural differences between the two genomes are the result of distinct fractionation and rearrangements after WGD, and massive proliferation of LTR-retrotransposons. Moreover, GO enrichment analyses suggest an ongoing gene birth-death-innovation process occurring among the tandem duplicated genes, shaping the evolution of carnivory-associated functions. We also identified unique patterns of developmentally related genes that support the terrestrial life-form and body plan of U. reniformis. Collectively, our results provided additional insights into the evolution of the plastic and specialized Lentibulariaceae genomes.

Floral micromorphology and nectar composition of the early evolutionary lineage Utricularia (subgenus Polypompholyx, Lentibulariaceae).

Utricularia (Lentibulariaceae) is a genus comprising around 240 species of herbaceous, carnivorous plants. Utricularia is usually viewed as an insect-pollinated genus, with the exception of a few bird-pollinated species. The bladderworts Utricularia multifida and U. tenella are interesting species because they represent an early evolutionary Utricularia branch and have some unusual morphological characters in their traps and calyx. Thus, our aims were to (i) determine whether the nectar sugar concentrations and composition in U. multifida and U. tenella are similar to those of other Utricularia species from the subgenera Polypompholyx and Utricularia, (ii) compare the nectary structure of U. multifida and U. tenella with those of other Utricularia species, and (iii) determine whether U. multifida and U. tenella use some of their floral trichomes as an alternative food reward for pollinators. We used light microscopy, histochemistry, and scanning and transmission electron microscopy to address those aims. The concentration and composition of nectar sugars were analysed using high-performance liquid chromatography. In all of the examined species, the floral nectary consisted of a spur bearing glandular trichomes. The spur produced and stored the nectar. We detected hexose-dominated (fructose + glucose) nectar in U. multifida and U. tenella as well as in U. violacea. In both U. multifida and U. tenella, there were trichomes that blocked the entrance into the throat and spur. Because these trichomes were rich in chromoplasts and contained lipid droplets, they may form an additional visual attractant. Bearing in mind the phylogenetic hypothesis for the genus, we suggest that an early ancestor of Utricularia had a nectariferous spur flower with a lower lip that formed a wide landing platform for bee pollinators.

The Trap Architecture of Utricularia multifida and Utricularia westonii (subg. Polypompholyx).

Utricularia are carnivorous plants which have small hollow vesicles as suction traps that work underwater by means of negative pressure and watertightness of the entrance for capturing small animal prey. Utricularia multifida and U. westonii have specific thick-walled traps, which are triangular in a transverse section but their functioning is unclear. Some authors suggest that the trap door in U. multifida acts as a simple valve without a suction trapping mechanism. Our main aim was to check the anatomical trap characters that are responsible for possible water outflow and maintaining negative pressure as main functional parts of the active trap suction mechanism in both species. Using different microscopic techniques, we investigated the ultrastructure of external trap glands, quadrifids, glands near the entrance (bifids, monofids), and also pavement epithelium. Quadrifids of both species have a similar structure to those known in other species from the genus, which possess the suction trap mechanism. Glands near the entrance in U. multifida and U. westonii, which are responsible for water pumping in other species, are typically developed as in other species in the genus and have pedestal cells which are transfer cells. The transfer cells also occur in glands of the pavement epithelium, which is again typically developed as in other species in the genus. Simple biophysical tests did not confirm reliably neither the negative underpressure formation in the traps nor the watertightness of the entrance in both species. Our anatomical results indirectly support the hypothesis that both species have suction traps like all other Utricularia species, but the biophysical data rather suggest a passive valve mechanism.

The Structure and Occurrence of a Velum in Utricularia Traps (Lentibulariaceae).

Bladderworts (Utricularia, Lentibulariaceae, Lamiales) are carnivorous plants that form small suction traps (bladders) for catching invertebrates. The velum is a cuticle structure that is produced by specialized trichomes of the threshold pavement epithelium. It is believed that the velum together with the mucilage seals the free edge of the trap door and that it is necessary for correct functioning of the trap. However, recently, some authors have questioned the occurrence of a velum in the traps of the Utricularia from the various sections. The main aim of this study was to confirm whether velum occurs in the traps of the Utricularia species from the subgenera Polypompholyx, Bivalvaria, and Utricularia. The 15 species were examined from subg. Polypompholyx, subg. Bivalvaria, and subg. Utricularia. A velum was found in all examined Utricularia species. In the traps of the members of section Pleiochasia, there was an outer velum (forming a complete ring) and an inner velum. In the traps of Utricularia uniflora (Lasiocaules), there was only an inner velum. In these species, the formation of the velum was accompanied by intensive mucilage production, and as a result, when door was closed (set position), the mucilage and the velum touched the surface of the door. In members of both sections of Pleiochasia and Lasiocaules, the pavement epithelium had a more complicated structure (four to five zones) than in the members of the subgenera Bivalvaria and Utricularia in which three distinct zones occurred (an outer with a velum, a middle and an internal with the mucilage trichomes). Even in U. purpurea, where the threshold was a reduced pavement epithelium, it consisted of three functional zones and the presence of a velum. Two main types of velum have been proposed. A velum was present in Utricularia traps regardless of the trap type or the habitat (aquatic, epiphytic, and terrestrial species). We proposed broad definition of velum as cuticle membranes covered by mucilage; from a functional point of view, this definition is more useful and more reflects complexity of this structure.

Floral micromorphology of the bird-pollinated carnivorous plant species Utricularia menziesii R.Br. (Lentibulariaceae).

Background and Aims: Bird pollination is rare among species in the genus Utricularia, and has evolved independently in two lineages of this genus. In Western Australia, the Western Spinebill, Acanthorhynchus superciliosus, visits flowers of Utricularia menziesii (section Pleiochasia: subgenus Polypompholyx). This study aimed to examine the micromorphology of U. menziesii flowers to assess traits that might be linked to its pollination strategy. Methods: Light microscopy, histochemistry and scanning electron microscopy were used. Nectar sugar composition was analysed using high-performance liquid chromatography. Key Results: The flowers of U. menziesii fulfil many criteria that characterize bird-pollinated flowers: red colour, a large, tough nectary spur that can withstand contact with a hard beak, lack of visual nectar guides and fragrance. Trichomes at the palate and throat may act as tactile signals. Spur nectary trichomes did not form clearly visible patches, but were more frequently distributed along vascular bundles, and were small and sessile. Each trichome comprised a single basal cell, a unicellular short pedestal cell (barrier cell) and a multicelled head. These trichomes were much smaller than those of the U. vulgaris allies. Hexose-dominated nectar was detected in flower spurs. Fructose and glucose were present in equal quantities (43 ± 3.6 and 42 ± 3.6 g L-1). Sucrose was only detected in one sample, essentially at the limit of detection for the method used. This type of nectar is common in flowers pollinated by passerine perching birds. Conclusions: The architecture of nectary trichomes in U. menziesii was similar to that of capitate trichomes of insect-pollinated species in this genus; thus, the most important specializations to bird pollination were flower colour (red), and both spur shape and size modification. Bird pollination is probably a recent innovation in the genus Utricularia, subgenus Polypompholyx, and is likely to have evolved from bee-pollinated ancestors.