RNA viral communities are structured by host plant phylogeny in oak and conifer leaves

Wild plants can suffer devastating diseases, experience asymptomatic, persistent infections, and serve as reservoirs for viruses of agricultural crops, yet we have a limited understanding of the natural plant virosphere. To access representatives of locally and globally distinct wild plants and investigate their viral diversity, we extracted and sequenced dsRNA from leaves from 16 healthy oak and conifer trees in the UC Davis Arboretum (Davis, California). From de novo assemblies, we recovered 389 RNA-dependent RNA polymerase (RdRp) gene sequences from 384 putative viral species, and a further 580 putative viral contigs were identified with virus prediction software followed by manual confirmation of virus annotation. Based on similarity to known viruses, most recovered viruses were predicted to infect plants or fungi, with the highest diversity and abundance observed in the Totiviridae and Mitoviridae families. Phyllosphere viral community composition differed significantly by host plant phylogeny, suggesting the potential for host-specific viromes. The phyllosphere viral community of one oak tree differed substantially from other oak viral communities and contained a greater proportion of putative mycoviral sequences, potentially due to the tree's more advanced senescence at the time of sampling. These results suggest that oaks and conifers harbor a vast diversity of viruses with as-yet unknown roles in plant health and phyllosphere microbial ecology.

Can Electrochemical Sensors Be Used for Identification and Phylogenetic Studies in Lamiaceae?

Electrochemical sensors have shown potential in recent years for plant species identification and phylogenetic studies. These works have been used to investigate the affinities of different species in many genera. However, the ability of electrochemical sensors to study relationships between different genera within a family has not been investigated. In this work, we selected 31 species in the Labiatae and 5 exotaxa as subjects to investigate the feasibility of electrochemical sensors at the genus level. The results show that electrochemical sensors are still very effective for the identification of these plants. Different pattern recognition techniques can make the identification more efficient. Also, the fingerprint profiles collected by the sensors can be used for phylogenetic studies of Labiatae. The phylogram divides all the species into five clusters, where the exotaxa are in one cluster. Species in the Labiatae are mainly distributed in four other clusters. Importantly, the different genera of species all showed close affinities, representing that electrochemical fingerprinting can well distinguish the affinities between the different genera. The results of this work demonstrate the great potential of electrochemical sensors in the study of plant phylogeny. Its application is not limited to the study at the species level, but can be extended to the genus level.

Plastid phylogenomic insights into relationships of all flowering plant families

Background Flowering plants (angiosperms) are dominant components of global terrestrial ecosystems, but phylogenetic relationships at the familial level and above remain only partially resolved, greatly impeding our full understanding of their evolution and early diversification. The plastome, typically mapped as a circular genome, has been the most important molecular data source for plant phylogeny reconstruction for decades. Results Here, we assembled by far the largest plastid dataset of angiosperms, composed of 80 genes from 4792 plastomes of 4660 species in 2024 genera representing all currently recognized families. Our phylogenetic tree (PPA II) is essentially congruent with those of previous plastid phylogenomic analyses but generally provides greater clade support. In the PPA II tree, 75% of nodes at or above the ordinal level and 78% at or above the familial level were resolved with high bootstrap support (BP ≥ 90). We obtained strong support for many interordinal and interfamilial relationships that were poorly resolved previously within the core eudicots, such as Dilleniales, Saxifragales, and Vitales being resolved as successive sisters to the remaining rosids, and Santalales, Berberidopsidales, and Caryophyllales as successive sisters to the asterids. However, the placement of magnoliids, although resolved as sister to all other Mesangiospermae, is not well supported and disagrees with topologies inferred from nuclear data. Relationships among the five major clades of Mesangiospermae remain intractable despite increased sampling, probably due to an ancient rapid radiation. Conclusions We provide the most comprehensive dataset of plastomes to date and a well-resolved phylogenetic tree, which together provide a strong foundation for future evolutionary studies of flowering plants.

Plant phylogeny as a major predictor of flower visitation by nitidulid beetles, a lineage of ancestral angiosperm pollinators

Plant phylogeny sometimes predicts interspecific variation in pollinator composition better than floral features, and its predictive value seems to differ among major groups of insect pollinators. Earlier findings suggesting that pollination by Plant phylogeny sometimes predicts interspecific variation in pollinator composition better than gross floral features, and its predictive value seems to differ among major groups of insect pollinators. Pollination by beetles exhibits the strongest phylogenetic signal and the strongest phylogenetic conservatism, which is particularly intriguing given that beetles were probably the pollinators of early angiosperms. We examine in this paper the relationship between plant phylogeny and flower visitation by nitidulid beetles (Coleoptera: Nitidulidae), an old monophyletic group of flower specialists and pollinators of gymnosperms and angiosperms. Using quantitative data on pollinator composition for 251 plant species (belonging to 167 genera in 46 families) from well-preserved Mediterranean montane habitats from southeastern Spain, the following questions were addressed: Is pollination by nitidulids correlated with plant phylogeny in the large species sample studied, and if it does, which are the relative importances of plant phylogeny, floral characteristics, and environmental features as predictors of nitidulid pollination in the plant assemblage studied ? Nitidulids were recorded in flowers of 25% of the plant species considered. Their distribution was significantly related to plant phylogeny, being clustered on certain lineages (Ranunculales, Malvales, Rosales, Asterales) and remarkably absent from others (e.g., Fabales, Lamiales). None of the environmental (habitat type, elevation) or macroscopic floral features considered (perianth type and color, flower mass) predicted nitidulid visitation after statistically accounting for the effect of plant phylogeny. We theorize that nitidulid beetles use characters of plants that track plant phylogeny at least as deep as the early radiation of the eudicots, imaginably characters such as the chemical signatures of pollen.

Beneath the Bark: Assessing Woody Stem Water and Carbon Fluxes and Its Prevalence Across Climates and the Woody Plant Phylogeny

While woody stems are known to influence carbon and water dynamics, direct exchange with the atmosphere is seldom quantified, limiting our understanding of how these processes influence the exchange of mass and energy. The presence of woody stem chlorophyll in a diversity of climates and across a range of species suggests an evolutionary advantage to sustaining carbon assimilation and water relations through permeable stem tissue. However, no formal evaluation of this hypothesis has been performed. In this mini-review, we explore the interactions between woody stems and the atmosphere by examining woody stem photosynthesis and bark-atmosphere water exchange. Specifically, we address the following questions: (1) How do water and carbon move between the atmosphere and woody stems? (2) In what climate space is woody stem photosynthesis and bark water uptake advantageous? (3) How ubiquitous across plant families is woody stem photosynthesis and bark-atmosphere water exchange? In the literature, only seven species have been identified as exhibiting bark water uptake while over 300 species are thought to conduct woody stem photosynthesis. The carbon dioxide and water gained from these processes can offset respiration costs and improve plant water balance. These species span diverse biomes suggesting a broad prevalence of bark-atmosphere permeability. Finally, our results demonstrate that there may be an evolutionary component as demonstrated by a high Pagel’s lambda for the presence of stem photosynthesis. We end with recommendations for future research that explores how bark water and carbon interactions may impact plant function and mass flow in a changing climate.

Spanning the Globe – The Plant Phylogeny Poster (PPP) Project

Historically, wallcharts and posters created by botanical illustrators, often highly skilled artists, have played an important role in teaching botany at the university level. Large-scale panels and posters can visualize complex interrelationships and entire stories in a clear and appealing overview in graphs, tables, and diagrams. Carrying this concept of educational tools into the electronic era, the Plant Phylogeny Poster project uses this approach for displaying evolutionary relationships in systematic botany. The Angiosperm Phylogeny Poster (APP) displays, as phylogenetically arranged clades, the orders and families of flowering plants (with orders hyperlinked to APweb, Stevens, 2001–onwards), the Tracheophyte Phylogeny Poster (TPP) families and genera of ferns and gymnosperms, and the Bryophyte Phylogeny Poster (BPP) orders and families of liverworts, mosses, and hornworts. The portfolio currently also includes about 30 posters on individual orders and families of angiosperms. Each group within these evolutionary trees is matched with essentially relevant morphological features, biogeographic occurrences, and other information in compactly condensed text blocks. All posters are freely available online, some in more than 30 languages, coauthored by a team of more than 130 botanists. The posters are regularly updated, current literature is cited. The project is expanding steadily and rapidly.

Gene duplications and genomic conflict underlie major pulses of phenotypic evolution in gymnosperms

Inferring the intrinsic and extrinsic drivers of species diversification and phenotypic disparity across the Tree of Life is a major challenge in evolutionary biology. In green plants, polyploidy (or whole-genome duplication, WGD) is known to play a major role in microevolution and speciation, but the extent to which WGD has shaped macroevolutionary patterns of diversification and phenotypic innovation across plant phylogeny remains an open question. Here we examine the relationship of various facets of genomic evolution (including gene and genome duplication, genome size, and chromosome number) with macroevolutionary patterns of phenotypic innovation, species diversification, and climatic occupancy in gymnosperms. We show that genomic changes, including WGD, underlie the origins of most major gymnosperm clades, and that spikes of gene duplication typically coincide with major spikes of phenotypic innovation. Increased rates of phenotypic evolution, however, are typically found at nodes with high gene-tree conflict, representing historic population-level dynamics during speciation. Most shifts in gymnosperm diversification since the rise of angiosperms are decoupled from putative WGDs and instead are associated with increased rates of climatic occupancy evolution, particularly in cooler and/or more arid climatic conditions, suggesting that ecological opportunity, especially in the latter Cenozoic, and environmental heterogeneity have driven a resurgence of gymnosperm diversification. Our study provides critical insight on the processes underlying diversification and phenotypic evolution in gymnosperms, with important broader implications for the major drivers of both micro- and macroevolution in plants.

Scanning electron microscopy observations of pollen morphology in common vetch (Vicia sativa) subspecies

Common vetch (Vicia sativa) is an important forage and green manure crop that is widely cultivated around the world. However, the large number of subspecies and accessions of common vetch has made taxonomic research on this species difficult. Pollen morphology data can provide important evidence in the study of plant phylogeny. Therefore, in this research, light microscopy and scanning electron microscopy were used to observe seven morphological traits of pollens from 22 common vetch accessions, and residual maximum likelihood and pattern analysis was conducted. The results showed that the pollen grains of the 22 accessions were all monad pollen and the polar view revealed three-lobed circular and triangular shapes, while the equatorial view mainly revealed an oblate shape; only one accession showed an oblate spherical shape. All accessions were 3-zonocolporate and the colpus length extended close to the poles. The polar axis length was (19.39 ± 0.97)–(42.12 ± 0.76) μm and the equatorial axis length was (35.97 ± 1.27)–(45.25 ± 0.81) μm. We found that qualitative traits of pollen shape, aperture polar view and ornamentation were highly stable. Among them, polar axis length, equatorial axis length and colpus length and width had significant differences among the accessions. The ratios of the equatorial and polar axes had significant differences among the subspecies. This trait information could be used for the classification and identification of common vetch accessions and subspecies.

Plant Phylogeny Posters – Concise Overviews of Plant Phylogeny now in Czech and Slovak

The Plant Phylogeny Posters (PPP) project is a free and regularly updated portfolio providing details of phylogenetic relationships of extant lineages of plants in a clear and appealing format for academia and general interest groups. The portfolio consists of three main posters: Angiosperm Phylogeny Poster (APP), Tracheophyte Phylogeny Poster (TPP), Bryophyte Phylogeny Poster (BPP), plus 30 posters of selected orders and families of angiosperms. Each poster depicts a tree showing the evolutionary relationships of a particular group on the level of orders, families, or genera also listing important apomorphic, plesiomorphic and diagnostic traits. The electronic format of these posters allows for regular updates based on most recent research results – thus the topology of the trees is largely up-to-date. All posters are freely available on ResearchGate and on the webpages of the authors.

Pollen sterols are associated with phylogenetics and environment but not with pollinators

SummaryPhytosterols are primary plant metabolites that have fundamental structural and regulatory functions. They are also essential nutrients for phytophagous insects, including pollinators, that cannot synthesize sterols. Despite the well-described composition and diversity in vegetative plant tissues, few studies have examined phytosterol diversity in pollen.We quantified 25 pollen phytosterols in 122 plant species (105 genera, 51 families) to determine their composition and diversity across plant taxa. We searched literature and databases for plant phylogeny, environmental conditions, and pollinator guilds of the species to examine the relationships with pollen sterols.24-methylenecholesterol, sitosterol and isofucosterol were the most common and abundant pollen sterols. We found phylogenetic clustering of twelve individual sterols, total sterol content and sterol diversity, and of sterol groupings that reflect their underlying biosynthesis pathway (24 carbon alkylation, ring B desaturation). Plants originating in tropical-like climates (higher mean annual temperature, lower temperature seasonality, higher precipitation in wettest quarter) were more likely to record higher pollen sterol content. However, pollen sterol composition and content showed no clear relationship with pollinator guilds.Our study is the first to show that pollen sterol diversity is phylogenetically clustered and that pollen sterol content may adapt to environmental conditions.