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Summary: The root epidermis of tracheophytes consists of hair‐forming cells (HCs) and nonhair cells (NCs). The HC distribution pattern is classified into three types: random (Type I), vertically alternating (Type II), and radial (Type III). Type III is found only in core eudicots and is known to be position‐dependent in superrosids with HCs positioned between two underlying cortical cells. However, the evolution of Type III and the universality of its position dependency in eudicots remain unclear.We surveyed the HC distribution in basal and Type III‐exhibiting core eudicots and conducted genomic analyses to get insight into whether eudicots share the same genetic network to establish Type III.Our survey revealed no canonical Type III in basal eudicots but a reverse Type III, with NCs between two cortical cells and HCs on a single cortical cell, in Papaveraceae of basal eudicots. Type III‐exhibiting species from both superrosids and superasterids showed the canonical position dependency of HCs. However, some key components for Type III determination were absent in the genomes of Papaveraceae and Type III‐exhibiting superasterids.Our findings identify a novel position‐dependent type of HC patterning, reverse Type III, and suggest that Type III emerged independently or diversified during eudicot evolution. [ABSTRACT FROM AUTHOR]

Premise: The use of hybrid breeding systems to increase crop yields has been the cornerstone of modern agriculture and is exemplified in the breeding and improvement of cultivated sunflower (Helianthus annuus). However, it is poorly understood what effect supporting separate breeding pools in such systems, combined with continued selection for yield, may have on leaf ecophysiology and specialized metabolite variation. Methods: We analyzed 288 lines of cultivated H. annuus to examine the genomic basis of several specialized metabolites and agronomically important traits across major heterotic groups. Results: Heterotic group identity supports phenotypic divergences between fertility restoring and cytoplasmic male‐sterility maintainer lines in leaf ecophysiology and specialized metabolism. However, the divergence is not associated with physical linkage to nuclear genes that support current hybrid breeding practices in cultivated H. annuus. Additionally, we identified four genomic regions associated with leaf ecophysiology and specialized metabolism that colocalize with previously identified QTLs for quantitative self‐compatibility traits and with S‐protein homolog (SPH) proteins, a recently discovered family of proteins associated with self‐incompatibility and self/nonself recognition in Papaver rhoeas (common poppy) with suggested conserved downstream mechanisms among eudicots. Conclusions: Further work is necessary to confirm the self‐incompatibility mechanisms in cultivated H. annuus and their relationship to the integrative and polygenic architecture of leaf ecophysiology and specialized metabolism in cultivated sunflower. However, because self‐compatibility is a derived quantitative trait in cultivated H. annuus, trait linkage to divergent phenotypic traits may have partially arisen as a potential unintended consequence of historical breeding practices and selection for yield. [ABSTRACT FROM AUTHOR]

Background Like all plant cells, the guard cells of stomatal complexes are encased in cell walls that are composed of diverse, interacting networks of polysaccharide polymers. The properties of these cell walls underpin the dynamic deformations that occur in guard cells as they expand and contract to drive the opening and closing of the stomatal pore, the regulation of which is crucial for photosynthesis and water transport in plants. Scope Our understanding of how cell wall mechanics are influenced by the nanoscale assembly of cell wall polymers in guard cell walls, how this architecture changes over stomatal development, maturation and ageing and how the cell walls of stomatal guard cells might be tuned to optimize stomatal responses to dynamic environmental stimuli is still in its infancy. Conclusion In this review, we discuss advances in our ability to probe experimentally and to model the structure and dynamics of guard cell walls quantitatively across a range of plant species, highlighting new ideas and exciting opportunities for further research into these actively moving plant cells. [ABSTRACT FROM AUTHOR]

Reconstructing evolutionary trajectories and transitions that have shaped floral diversity relies heavily on the phylogenetic framework on which traits are modelled. In this study, we focus on the angiosperm order Ranunculales, sister to all other eudicots, to unravel higher-level relationships, especially those tied to evolutionary transitions in flower symmetry within the family Papaveraceae. This family presents an astonishing array of floral diversity, with actinomorphic, disymmetric (two perpendicular symmetry axes), and zygomorphic flowers. We generated nuclear and plastid datasets using the Angiosperms353 universal probe set for target capture sequencing (of 353 single-copy nuclear ortholog genes), together with publicly available transcriptome and plastome data mined from open-access online repositories. We relied on the fossil record of the order Ranunculales to date our phylogenies and to establish a timeline of events. Our phylogenomic workflow shows that nuclear-plastid incongruence accompanies topological uncertainties in Ranunculales. A cocktail of incomplete lineage sorting, post-hybridization introgression, and extinction following rapid speciation most likely explain the observed knots in the topology. These knots coincide with major floral symmetry transitions and thus obscure the order of evolutionary events. [ABSTRACT FROM AUTHOR]

Discussing homology relationships among secretory structures remains a relatively underexplored area in botanical research. These structures are widely dispersed within Malpighiales, one of the largest orders of eudicots. Within Malpighiales, both extranuptial and nuptial nectaries are present, and they do not seem homoplastic or share evolutionary connections. Particularly in Malpighiaceae, extensive research has focused on the ecological interactions mediated by glands. Botanists largely agree that elaiophores in sepals of Neotropical Malpighiaceae have evolved from extrafloral nectaries on leaves. However, the evolutionary origin of elaiophores has yet to be thoroughly examined, particularly in comparison to outgroups. This study provides empirical evidence on the ontogeny of elaiophores and investigates their evolutionary origins and homology relationships across different lineages of Malpighiales using comparative anatomy. Our findings suggest that elaiophores are likely homologous to extranuptial nectaries found in sepals of other Malpighiales lineages, originating from nectaries on leaves. This discussion is a starting point for future studies exploring the evolution of nectaries found in flowers, whether extranuptial or nuptial, and their potential origins from nectaries in vegetative organs such as leaves. Understanding these relationships could shed light on the selective pressures influencing floral morphologies. [ABSTRACT FROM AUTHOR]

Water balance is crucial for the growth and flowering of plants. However, the mechanisms by which flowers maintain water balance are poorly understood across different angiosperm branches.Here, we investigated 29 floral hydraulic and economic traits in 24 species from ANA grade, magnoliids, monocots, and eudicots. Our main objective was to compare differences in flower water use strategies between basal angiosperms (ANA grade and magnoliids) and derived group (monocots and eudicots).We found that basal angiosperms had richer petal stomatal density, higher pedicel hydraulic diameter, and flower mass per area, but lower pedicel vessel wall reinforcement and epidermal cell thickness compared to monocots and eudicots. We also observed significant trade‐offs and coordination among different floral traits. Floral traits associated with reproduction, such as floral longevity and size, were strongly linked with physiological and anatomical traits.Our results systematically reveal the variation in flower economic and hydraulic traits from different angiosperm branches, deepening understanding of flower water use strategies among these plant taxa. We conclude that basal angiosperms maintain water balance with high water supply, whereas monocots and eudicots maintain a more conservative water balance. [ABSTRACT FROM AUTHOR]

Menispermaceae species, as early‐diverging eudicots, can synthesize valuable benzylisoquinoline alkaloids (BIAs) like bisbenzylisoquinoline alkaloids (bisBIAs) and sinomenines with a wide range of structural diversity. However, the evolutionary mechanisms responsible for their chemo‐diversity are not well understood. Here, a chromosome‐level genome assembly of Menispermum dauricum is presented and demonstrated the occurrence of two whole genome duplication (WGD) events that are shared by Ranunculales and specific to Menispermum, providing a model for understanding chromosomal evolution in early‐diverging eudicots. The biosynthetic pathway for diverse BIAs in M. dauricum is reconstructed by analyzing the transcriptome and metabolome. Additionally, five catalytic enzymes – one norcoclaurine synthase (NCS) and four cytochrome P450 monooxygenases (CYP450s) – from M. dauricum are responsible for the formation of the skeleton, hydroxylated modification, and C‐O/C‐C phenol coupling of BIAs. Notably, a novel leaf‐specific MdCYP80G10 enzyme that catalyzes C2′‐C4a phenol coupling of (S)‐reticuline into sinoacutine, the enantiomer of morphinan compounds, with predictable stereospecificity is discovered. Moreover, it is found that Menispermum‐specific CYP80 gene expansion, as well as tissue‐specific expression, has driven BIA diversity in Menispermaceae as compared to other Ranunculales species. This study sheds light on WGD occurrences in early‐diverging eudicots and the evolution of diverse BIA biosynthesis. [ABSTRACT FROM AUTHOR]

Living fossils are evidence of long-term sustained ecological success. However, whether living fossils have little molecular changes remains poorly known, particularly in plants. Here, we have introduced a novel method that integrates phylogenomic, comparative genomic, and ecological niche modeling analyses to investigate the rate of molecular evolution of Eupteleaceae, a Cretaceous relict angiosperm family endemic to East Asia. We assembled a high-quality chromosome-level nuclear genome, and the chloroplast and mitochondrial genomes of a member of Eupteleaceae (Euptelea pleiosperma). Our results show that Eupteleaceae is most basal in Ranunculales, the earliest-diverging order in eudicots, and shares an ancient whole-genome duplication event with the other Ranunculales. We document that Eupteleaceae has the slowest rate of molecular changes in the observed angiosperms. The unusually low rate of molecular evolution of Eupteleaceae across all three independent inherited genomes and genes within each of the three genomes is in association with its conserved genome architecture, ancestral woody habit, and conserved niche requirements. Our findings reveal the evolution and adaptation of living fossil plants through large-scale environmental change and also provide new insights into early eudicot diversification. [ABSTRACT FROM AUTHOR]

Angiosperms (flowering plants) are by far the most diverse land plant group with over 300,000 species. The sudden appearance of diverse angiosperms in the fossil record was referred to by Darwin as the "abominable mystery," hence contributing to the heightened interest in angiosperm evolution. Angiosperms display wide ranges of morphological, physiological, and ecological characters, some of which have probably influenced their species richness. The evolutionary analyses of these characteristics help to address questions of angiosperm diversification and require well resolved phylogeny. Following the great successes of phylogenetic analyses using plastid sequences, dozens to thousands of nuclear genes from next‐generation sequencing have been used in angiosperm phylogenomic analyses, providing well resolved phylogenies and new insights into the evolution of angiosperms. In this review we focus on recent nuclear phylogenomic analyses of large angiosperm clades, orders, families, and subdivisions of some families and provide a summarized Nuclear Phylogenetic Tree of Angiosperm Families. The newly established nuclear phylogenetic relationships are highlighted and compared with previous phylogenetic results. The sequenced genomes of Amborella, Nymphaea, Chloranthus, Ceratophyllum, and species of monocots, Magnoliids, and basal eudicots, have facilitated the phylogenomics of relationships among five major angiosperms clades. All but one of the 64 angiosperm orders were included in nuclear phylogenomics with well resolved relationships except the placements of several orders. Most families have been included with robust and highly supported placements, especially for relationships within several large and important orders and families. Additionally, we examine the divergence time estimation and biogeographic analyses of angiosperm on the basis of the nuclear phylogenomic frameworks and discuss the differences compared with previous analyses. Furthermore, we discuss the implications of nuclear phylogenomic analyses on ancestral reconstruction of morphological, physiological, and ecological characters of angiosperm groups, limitations of current nuclear phylogenomic studies, and the taxa that require future attention. [ABSTRACT FROM AUTHOR]

Coptis chinensis Franch., also named Chinese goldthread is a member of Ranunculaceae in the order Ranunculales and represents an important lineage of early eudicots with traditional medicinal value. In our study, by using syntenic analysis combined with phylogenomic analysis of C. chinensis and four other representative genomes from basal and core eudicots, we confirmed that the WGD event in C. chinensis was shared by Aquilegia coerulea and Papaver somniferum L. and quickly occurred after Ranunculales diverged from other eudicots, likely a Ranunculales common tetraploidization (RCT). The synonymous nucleotide substitutions at synonymous sites distribution of syntenic blocks across these genomes showed that the evolutionary rate of the P. somniferum genome is faster than that of the C. chinensis genome by approximately 13.7%, possibly due to Papaveraceaes having an additional special tetraploidization event (PST). After Ks correction, the RCT dated to 115-130 million years ago (MYA), which was close to the divergence of Ranunculaceaes and Papaveraceaes approximately 115.45-130.51 MYA. Moreover, we identified homologous genes related to polyploidization and speciation and constructed multiple sequence alignments with different reference genomes. Notably, the event-related subgenomes in the basal genomes all showed genomic fractionation bias, suggesting a likely allopolyploid nature of the RCT, PST and T-Alpha and T-Beta events in Tetracentron sinense. In addition, we detected that the sixteen P450 subfamilies were markedly expanded in the genomes of Ranunculales, and most of them were related to the RCT and PST events. We constructed a new platform for Early Eudicot Comparative Genomic Research (http://www.cgrpoee.top/index.html) to store more information. In summary, our findings support the WGD of C. chinensis shared by Ranunculales, which is likely an allotetraploidization event. This present effort offered new insights into the evolution of key polyploidization events and the genes related to secondary metabolites during the diversification of early eudicots. [ABSTRACT FROM AUTHOR]

We describe a new fossil wood genus of Anacardiaceae with two species from the Tepetate Formation (upper Eocene), Baja California Sur State, Mexico. The first species has distinct growth ring boundaries, vessels solitary and in radial multiples; alternate intervessel pitting, and the vessel-ray parenchyma pits with reduced borders. Its other features are: non-septate and septate fibers, axial parenchyma rare, and rays mostly uniseriate except for those with radial canals. The second species has distinct growth ring boundaries, vessels solitary and in radial multiples (a higher percentage of solitary vessels than the first species), vessel-ray pits with a horizontal to round shape, all fibers nonseptate, vasicentric axial parenchyma, heterocellular rays and radial canals in some multiseriate rays. The diagnostic traits in both woods allow us to erect in a new fossil genus, Pericuxylon with two species in the Anacardiaceae family. The occurrence of Anacardiaceae in the late Eocene of southern Baja California Sur confirms its long geological history and importance in forests of northern Mexico. • Key words: Baja California Peninsula, eudicots, fossil woods, Sapindales. [ABSTRACT FROM AUTHOR]

Recently, the siRNAs pathways, and especially reproductive phasiRNAs, have attracted attention in eudicots since their biological roles are still unknown and their biogenesis took different evolutionary pathways compared to monocots. In this work, we used Coffea arabica L., a recent allotetraploid formed from the hybridization of Coffea canephora and C. eugenioides unreduced gametes, to explore microsporogenesis and small RNAs‐related pathways in a eudicot crop. First, we identified the microsporogenesis stages during anther development revealing that pre‐meiosis occurs in anthers of 1.5 mm inside floral buds (FBs), whereas meiosis between 1.5 and 4.2 mm FBs, and post‐meiosis in FBs larger than 4.2 mm. These stages coincide with the Brazilian winter, a period of FBs reduced growth which suggests temperature sensitivity. Next, we identified and quantified the expression of reproductive 21‐ and 24‐nt phasiRNAs during coffee anther development together with their canonical and novel miRNA triggers, and characterized the DCL and AGO families. Our results showed that the pattern of reproductive phasiRNA abundance in C. arabica is unique among described eudicots and the canonical trigger car‐miR2275 is involved in the processing of both 21‐ and 24‐nt phasiRNAs. Fourteen DCL genes were identified, but DCL5, related to phasiRNA biosynthesis in monocots, was not, according to its specificity for monocots. Thus, our work explored the knowledge gap about microsporogenesis and related siRNAs pathways in coffee, contributing to the control of reproductive development and the improvement of fertility in eudicots. [ABSTRACT FROM AUTHOR]

A total of 338 species of Angiosperms belonging to 247 genera and 80 families have been recorded from Lungmaiching Hill Ranges located in Imphal east district, Manipur. The recorded species are classified under APG IV. Of these, highest species diversity is shown by Eudicots with 240 species, followed by Monocots with 84 species, Magnolids with 13 species, etc. The species composition is dominated by herbs (121 spp.) and trees (104 spp.) while others are represented by shrubs (76 spp.), epiphytes (21 spp.), climbers (15 spp.) and creeper (1 sp.). At family level, Fabaceae (22 spp.) showed highest species content and is followed by Orchidaceae (21 spp.), Asteraceae (21 spp.), Poaceae (20 spp.) and Moraceae (16 spp.). The study also reported Lasia spinosa (L.) Thwaites and Ficus hirta Vahl as new additions to the flora of Manipur. [ABSTRACT FROM AUTHOR]

The structures of cell wall mannan hemicelluloses have changed during plant evolution. Recently, a new structure called β-galactoglucomannan (β-GGM) was discovered in eudicot plants. This galactoglucomannan has β-(1,2)-Gal-α-(1,6)-Gal disaccharide branches on some mannosyl residues of the strictly alternating Glc-Man backbone. Studies in Arabidopsis revealed β-GGM is related in structure, biosynthesis and function to xyloglucan. However, when and how plants acquired β-GGM remains elusive. Here, we studied mannan structures in many sister groups of eudicots. All glucomannan structures were distinct from β-GGM. In addition, we searched for candidate mannan β-galactosyltransferases (MBGT) in non-eudicot angiosperms. Candidate AtMBGT1 orthologues from rice (OsGT47A-VII) and Amborella (AtrGT47A-VII) did not show MBGT activity in vivo. However, the AtMBGT1 orthologue from rice showed MUR3-like xyloglucan galactosyltransferase activity in complementation analysis using Arabidopsis. Further, reverse genetic analysis revealed that the enzyme (OsGT47A-VII) contributes to proper root growth in rice. Together, gene duplication and diversification of GT47A-VII in eudicot evolution may have been involved in the acquisition of mannan β-galactosyltransferase activity. Our results indicate that β-GGM is likely to be a eudicot-specific mannan. [ABSTRACT FROM AUTHOR]

The MIXTA family of MYB transcription factors modulate the development of diverse epidermal features in land plants. This study investigates the evolutionary history and function of the MIXTA gene family in the early-diverging eudicot model lineage Thalictrum (Ranunculaceae), with R2R3 SBG9-A MYB transcription factors representative of the pre-core eudicot duplication and thus hereby referred to as “paleoMIXTA” (PMX). Cloning and phylogenetic analysis of Thalictrum paleoMIXTA (ThPMX) orthologs across 23 species reveal a genus-wide duplication coincident with a whole-genome duplication. Expression analysis by qPCR confirmed that the highest expression is found in carpels, while newly revealing high expression in leaves and nuanced differences between paralogs in representative polyploid species. The single-copy ortholog from the diploid species T. thalictroides (TthPMX, previously TtMYBML2), which has petaloid sepals with conical–papillate cells and trichomes on leaves, was functionally characterized by virus-induced gene silencing (VIGS), and its role in leaves was also assessed from heterologous overexpression in tobacco. Another ortholog from a species with conical–papillate cells on stamen filaments, TclPMX, was also targeted for silencing. Overexpression assays in tobacco provide further evidence that the paleoMIXTA lineage has the potential for leaf trichome function in a core eudicot. Transcriptome analysis by RNA-Seq on leaves of VIGS-treated plants suggests that TthPMX modulates leaf trichome development and morphogenesis through microtubule-associated mechanisms and that this may be a conserved pathway for eudicots. These experiments provide evidence for a combined role for paleoMIXTA orthologs in (leaf) trichomes and (floral) conical–papillate cells that, together with data from other systems, makes the functional reconstruction of a eudicot ancestor most likely as also having a combined function. [ABSTRACT FROM AUTHOR]

C₄ is one of three known photosynthetic processes of carbon fixation in flowering plants. It evolved independently more than 61 times in multiple angiosperm lineages and consists of a series of anatomical and biochemical modifications to the ancestral C3 pathway increasing plant productivity under warm and light‐rich conditions. The C4 lineages of eudicots belong to seven orders and 15 families, are phylogenetically less constrained than those of monocots and entail an enormous structural and ecological diversity. Eudicot C4 lineages likely evolved the C4 syndrome along different evolutionary paths. Therefore, a better understanding of this diversity is key to understanding the evolution of this complex trait as a whole. By compiling 1207 recognised C4 eudicots species described in the literature and presenting trait data among these species, we identify global centres of species richness and of high phylogenetic diversity. Furthermore, we discuss climatic preferences in the context of plant functional traits. We identify two hotspots of C4 eudicot diversity: arid regions of Mexico/Southern United States and Australia, which show a similarly high number of different C4 eudicot genera but differ in the number of C4 lineages that evolved in situ. Further eudicot C4 hotspots with many different families and genera are in South Africa, West Africa, Patagonia, Central Asia and the Mediterranean. In general, C4 eudicots are diverse in deserts and xeric shrublands, tropical and subtropical grasslands, savannas and shrublands. We found C4 eudicots to occur in areas with less annual precipitation than C4 grasses which can be explained by frequently associated adaptations to drought stress such as among others succulence and salt tolerance. The data indicate that C4 eudicot lineages utilising the NAD‐ME decarboxylating enzyme grow in drier areas than those using the NADP‐ME decarboxylating enzyme indicating biochemical restrictions of the later system in higher temperatures. We conclude that in most eudicot lineages, C4 evolved in ancestrally already drought‐adapted clades and enabled these to further spread in these habitats and colonise even drier areas. [ABSTRACT FROM AUTHOR]

Benzoxazinoids (BXDs) form a class of indole-derived specialized plant metabolites with broad antimicrobial and antifeedant properties. Unlike most specialized metabolites, which are typically lineage-specific, BXDs occur sporadically in a number of distantly related plant orders. This observation suggests that BXD biosynthesis arose independently numerous times in the plant kingdom. However, although decades of research in the grasses have led to the elucidation of the BXD pathway in the monocots, the biosynthesis of BXDs in eudicots is unknown. Here, we used a metabolomic and transcriptomic-guided approach, in combination with pathway reconstitution in Nicotiana benthamiana, to identify and characterize the BXD biosynthetic pathways from both Aphelandra squarrosa and Lamium galeobdolon, two phylogenetically distant eudicot species. We show that BXD biosynthesis in A. squarrosa and L. galeobdolon utilize a dual-function flavin-containing monooxygenase in place of two distinct cytochrome P450s, as is the case in the grasses. In addition, we identified evolutionarily unrelated cytochrome P450s, a 2-oxoglutarate-dependent dioxygenase, a UDP-glucosyltransferase, and a methyltransferase that were also recruited into these BXD biosynthetic pathways. Our findings constitute the discovery of BXD pathways in eudicots. Moreover, the biosynthetic enzymes of these pathways clearly demonstrate that BXDs independently arose in the plant kingdom at least three times. The heterogeneous pool of identified BXD enzymes represents a remarkable example of metabolic plasticity, in which BXDs are synthesized according to a similar chemical logic, but with an entirely different set of metabolic enzymes. [ABSTRACT FROM AUTHOR]

The MIXTA family of MYB transcription factors modulate the development of diverse epidermal features in land plants. This study investigates the evolutionary history and function of the MIXTA gene family in the early-diverging eudicot model lineage Thalictrum (Ranunculaceae), with R2R3 SBG9-A MYB transcription factors representative of the pre-core eudicot duplication and thus hereby referred to as “paleoMIXTA” (PMX). Cloning and phylogenetic analysis of Thalictrum paleoMIXTA (ThPMX) orthologs across 23 species reveal a genus-wide duplication coincident with a whole-genome duplication. Expression analysis by qPCR confirmed that the highest expression is found in carpels, while newly revealing high expression in leaves and nuanced differences between paralogs in representative polyploid species. The single-copy ortholog from the diploid species T. thalictroides (TthPMX, previously TtMYBML2), which has petaloid sepals with conical–papillate cells and trichomes on leaves, was functionally characterized by virus-induced gene silencing (VIGS), and its role in leaves was also assessed from heterologous overexpression in tobacco. Another ortholog from a species with conical–papillate cells on stamen filaments, TclPMX, was also targeted for silencing. Overexpression assays in tobacco provide further evidence that the paleoMIXTA lineage has the potential for leaf trichome function in a core eudicot. Transcriptome analysis by RNA-Seq on leaves of VIGS-treated plants suggests that TthPMX modulates leaf trichome development and morphogenesis through microtubule-associated mechanisms and that this may be a conserved pathway for eudicots. These experiments provide evidence for a combined role for paleoMIXTA orthologs in (leaf) trichomes and (floral) conical–papillate cells that, together with data from other systems, makes the functional reconstruction of a eudicot ancestor most likely as also having a combined function.

Summary: One of Sherwin Carlquist's greatest scientific legacies is how far he advanced our understanding of the structural and functional relationships within the xylem. His research was critical in illuminating the occurrence and importance of tracheids co-occurring with vessels in the xylem of some eudicots. Here, we highlight key concepts and findings from his work on these topics, and how testing has advanced with the advent of recent methods that produce spatially explicit data on embolism formation. There are three classifications of tracheids within vessel-bearing xylem: vasicentric, true, and vascular. Carlquist viewed tracheids as critical in safely transporting water. We review the literature on tracheid function, focusing on transport safety and efficiency, and discuss how the presence of tracheids might affect other xylem traits in the context of tradeoffs. Available data indicate that Carlquist was correct in his view that tracheids are resistant to embolism, and they contribute to the safe transport of sap. Tracheids provide connections (bridges) among vessels that remain sap-filled within highly embolized vessel networks and, in this role, they promote embolism tolerance. There is still much to learn, and integrating tracheids into models of sap flow, understanding their pit traits and connections, and how they affect xylem functional tradeoffs will transform our understanding of plant sap transport. Diverse xylem structural arrangements suggest many potential ways for xylem networks to function. In species containing both vessels and tracheids, the hydraulic network appears to be able to tolerate high levels of vessel embolism within seasonal environments. [ABSTRACT FROM AUTHOR]

Anthocyanins are important water-soluble pigments that are widely found in plants and determine the color of plant organs, which possess significant health and economic value. The anthocyanin biosynthetic pathway is well established and some key regulators controlling this pathway have been identified in a variety of species. In recent years, microRNAs, transcription factors, and external factors, including light, temperature and hormones have emerged as central regulators of a variety of secondary metabolic responses, including anthocyanin metabolism, as both plant self-regulatory factors and environmental signals that stimulate plant development. Many discoveries have begun to suggest gene/signal-gene modules to reveal the signaling pathways involved in anthocyanin biosynthesis during fruit ripening and the links between specific genes. This paper reviews the internal and external factors and associated network mechanisms that regulate anthocyanin biosynthesis and accumulation in eudicots plants. miRNAs have different effects on the biosynthesis of anthocyanins in different species by binding to their target genes to form regulatory modules. The review also focuses on the conclusion that light signals (light quality, photoperiod, and light intensity) further regulate anthocyanin accumulation by binding to their corresponding photoreceptors (UVR8, CRYs, and PHYs) and affecting the binding and stabilization of the central regulators of the light pathway, such as COP1 and the transcription factor HY5. This article aims to provide a reference for future research on the regulation of anthocyanin by effective pathways, and to contribute to the selection of new varieties and the improvement of cultivation facilities. [ABSTRACT FROM AUTHOR]

Abstract Background Eudicots are the most diverse group of flowering plants that compromise five well-defined lineages: core eudicots, Ranunculales, Proteales, Trochodendrales, and Buxales. However, the phylogenetic relationships between these five lineages and their chromosomal evolutions remain unclear, and a lack of high-quality genome analyses for Buxales has hindered many efforts to address this knowledge gap. Results Here, we present a high-quality chromosome-level genome of Buxus austro-yunnanensis (Buxales). Our phylogenomic analyses revealed that Buxales and Trochodendrales are genetically similar and classified as sisters. Additionally, both are sisters to the core eudicots, while Ranunculales was found to be the first lineage to diverge from these groups. Incomplete lineage sorting and hybridization were identified as the main contributors to phylogenetic discordance (34.33%) between the lineages. In fact, B. austro-yunnanensis underwent only one whole-genome duplication event, and collinear gene phylogeny analyses suggested that separate independent polyploidizations occurred in the five eudicot lineages. Using representative genomes from these five lineages, we reconstructed the ancestral eudicot karyotype (AEK) and generated a nearly gapless karyotype projection for each eudicot species. Within core eudicots, we recovered one common chromosome fusion event in asterids and malvids, respectively. Further, we also found that the previously reported fused AEKs in Aquilegia (Ranunculales) and Vitis (core eudicots) have different fusion positions, which indicates that these two species have different karyotype evolution histories. Conclusions Based on our phylogenomic and karyotype evolution analyses, we revealed the likely relationships and evolutionary histories of early eudicots. Ultimately, our study expands genomic resources for early-diverging eudicots.

Phytolith studies of Neotropical vegetation history and its human influences require large modern reference collections from diverse woody and herbaceous plants. In order to further enlarge our reference collection, we analyzed phytoliths from 435 species of eudicotyledons from 84 families and 361 genera of mainly lowland Amazonian forest taxa along with other Neotropical plants. Our analysis revealed new morphologies from the silicification of bark in arboreal taxa that don't produce diagnostic vegetative phytoliths, as well as distinctive-looking phytoliths from leaves of previously unstudied trees. Several of the phytolith types uncovered here occur as unknowns in our earlier Amazonian terrestrial soil research. No morphotypes were revealed that overlapped with diagnostic phytoliths documented previously in other families and genera. Our reference collection now totals approximately 1540 Neotropical eudicotyledon species. For the Amazonian forest below 1000m it includes 80% of eudicotyledon families often with half or more of their genera and many of the most commonly occurring trees. A significant number of herbaceous and arboreal/woody taxa can be identified at the family, genus, and possibly species level for study of Neotropical vegetational and forest history. Phytolith and palynological investigations are excellent complements to each other. [ABSTRACT FROM AUTHOR]

The current study's objective is to infer the specific pollen morphologies of 27 different Euphorbia L. Turkish taxa were cultivated using LM and SEM. Additionally, principal component analysis (PCA) is developed and cluster analysis is used to examine similarity grouping in this study. The results of the current study showed that tricolporate pollen grains are present in 24 different taxa of Euphorbia, whereas three other taxa E. denticulate, E. esula subsp. tommassiniana, and E. orientalis have tricolpate and tricolporate pollen grains. The results of this study also revealed that pollen grains frequently have a perforated pattern. The use of ornamentations with reticulate- and rugulate-perforate surfaces has also been discovered. The current study revealed that six taxa of Euphorbia have prolate-spheroidal pollen shapes, while 20 of the 27 Euphorbia under study have oblate-spheroidal pollen shapes. But only the pollen of E. grisophylla, 1 of the 27 tested Euphorbia taxa, has a subprolate shape. On the other hand, the PCA results explained 92.16% of the variation, and the unweighted pair group method with arithmetic mean (UPGMA) dendrogram identified four taxonomic groupings, as follows: types 1–4. [ABSTRACT FROM AUTHOR]

In Petunia (Solanaceae family), self-incompatibility (SI) is regulated by the polymorphic S-locus, which contains the pistil-specific S-RNase and multiple pollen-specific S-Locus F-box (SLF) genes. SLFs assemble into E3 ubiquitin ligase complexes known as Skp1–Cullin1–F-box complexes (SCFSLF). In pollen tubes, these complexes collectively mediate ubiquitination and degradation of all nonself S-RNases, but not self S-RNase, resulting in cross-compatible, but self-incompatible, pollination. Using Petunia inflata, we show that two pollen-expressed Cullin1 (CUL1) proteins, PiCUL1-P and PiCUL1-B, function redundantly in SI. This redundancy is lost in Petunia hybrida, not because of the inability of PhCUL1-B to interact with SSK1, but due to a reduction in the PhCUL1-B transcript level. This is possibly caused by the presence of a DNA transposon in the PhCUL1-B promoter region, which was inherited from Petunia axillaris, one of the parental species of Pe. hybrida. Phylogenetic and syntenic analyses of Cullin genes in various eudicots show that three Solanaceae-specific CUL1 genes share a common origin, with CUL1-P dedicated to S-RNase-related reproductive processes. However, CUL1-B is a dispersed duplicate of CUL1-P present only in Petunia, and not in the other species of the Solanaceae family examined. We suggest that the CUL1s involved (or potentially involved) in the SI response in eudicots share a common origin. This work demonstrates the functional redundancy of PiCUL1-P and PiCUL1-B in SCFSLF complexes of Petunia inflata, and proposes evolutionary patterns of self-incompatibility-related CUL1s in eudicots. [ABSTRACT FROM AUTHOR]

Magnoliids are the largest flowering plant clades outside of the eudicots and monocots, which are distributed worldwide and have high economic, ornamental and ecological values. Eudicots, monocots and magnoliids are the three major clades of Mesangiospermae, and their phylogenetic relationship is one of the most interesting issues. In recent years, with the continuous accumulation of genomic information, the evolutionary status of magnoliids has become a hot spot in plant phylogenetic research. Although great efforts have been made to study the evolution of magnoliids using molecular data from several representative species such as nuclear genome, plastid genome, mitochondrial genome, and transcriptome, the results of current studies on the phylogenetic status of magnoliids are inconsistent. Here, we systematically describe the current understanding of the molecular research on magnoliid phylogeny and review the differences in the evolutionary state of magnoliids. Understanding the research approaches and limitations of magnoliid phylogeny can guide research strategies to further improve the study of the phylogenetic evolution of magnoliids. [ABSTRACT FROM AUTHOR]

Summary: Ester‐linked p‐coumarate (pCA) is a hallmark feature of the secondary cell walls in commelinid monocot plants. It has been shown that pCA groups arise during lignin polymerisation from the participation of monolignol conjugates assembled by p‐coumaroyl‐CoA:monolignol transferase (PMT) enzymes, members of the BAHD superfamily of acyltransferases.Herein, we report that a eudicot species, kenaf (Hibiscus cannabinus), naturally contains p‐coumaroylated lignin in the core tissues of the stems but not in the bast fibres. Moreover, we identified a novel acyltransferase, HcPMT, that shares <30% amino acid identity with known monocot PMT sequences.Recombinant HcPMT showed a preference in enzyme assays for p‐coumaroyl‐CoA and benzoyl‐CoA as acyl donor substrates and sinapyl alcohol as an acyl acceptor. Heterologous expression of HcPMT in hybrid poplar trees led to the incorporation of pCA in lignin, but no improvement in the saccharification potential of the wood.This work illustrates the value in mining diverse plant taxa for new monolignol acyltransferases. Furthermore, the occurrence of pCA outside monocot lineages may represent another example of convergent evolution in lignin structure. This discovery expands textbook views on cell wall biochemistry and provides a new molecular tool for engineering the lignin of biomass feedstock plants. [ABSTRACT FROM AUTHOR]

This study aimed to describe the morphological, anatomical and palynological properties of Acanthoprasium integrifolium (Benth.) Ryding, which is endemic in Cyprus. Plant samples were collected from Northern Cyprus. Morphological observations were made using a binocular stereo microscope with a drawing tube. For anatomical studies, the samples were conserved in 70% alcohol. The transverse and surface sections were taken by hand with a help razor blade. The nutlet micromorphologies and pollen properties were examined using scanning electron microscopy. In morphological studies, the description of A. integrifolium was given in detail for the first time and the general appearance of plant and leaf, bract, bracteole, flower, calyx, corolla and nutlet shapes were supported by drawings. The stem and leaf characteristics of the plant were examined in anatomical studies. The stem is almost tetragonal-rounded in shape. The vascular bundles are well-developed in the corners. The pith area covers a large area and includes simple crystals. The leaf is bifacial type and hypostomatic. The pollen grains are tricolpate and prolate shaped. While the surface of pollen grains is reticulate, the nutlets have scalariform ornamentation. [ABSTRACT FROM AUTHOR]

Eighty-nine new records of species were added to the list of urban ornamental plants of Tunja (Boyacá). This contribution is presented as a catalog with three taxonomic groups: Pteridophyta (2 families, 2 genera and 2 species), Eudicotyledons (21 families with 47 genera, 72 species and 1 cultivar) and Monocotyledons (7 families, 12 genera and 15 species). Within the families, the most important in terms of richness were the Cactaceae (with 13 genera and 21 species) and the Crassulaceae (with 8 genera and 21 species). Therefore, the growth habit that prevailed were succulents. Information such as the common name and origin of each species is provided, and photographs are also included. [ABSTRACT FROM AUTHOR]

Phytoliths are a good tool for investigating vegetation change in northern Australia. However, there is a lack of phytolith reference material across the Australian continent, particularly for woody plants. The development of reference material from woody plants is critical to understand regional patterns of phytolith production and preservation. This study analyses phytolith material from 40 woody plants to examine morphological and anatomical variation in phytolith production among Australian plant families. This is paired with phytolith assemblages from nine surface sediment samples to assess the representation and preservation of woody plant phytolith morphotypes. All woody plant species examined produce identifiable phytolith morphotypes, but most morphotypes cannot be differentiated between woody eudicots, monocots, and conifers. However, some woody plant morphotypes do have good potential for taxonomic or anatomical discrimination of plant groups. The analysis of surface sediment phytolith assemblages reveals that not all woody plant morphotypes preserve equally in surface sediments, potentially restricting their ability for taxonomic discrimination. Finally, the relevance of phytolith morphotypes for palaeoecological reconstruction is discussed. • Developing woody plant reference material is critical for phytolith analysis in Australia. • Australian trees and shrubs produce identifiable but largely redundant phytolith morphotypes. • Palms and woody eudicots produce differentiable, diagnostic phytolith morphotypes. • Acacia spp. produce distinct phytoliths, but these are not well represented in surface sediments. • Phytoliths can reconstruct tree:grass ratios and some tree types in northern Australia. [ABSTRACT FROM AUTHOR]

Abstract Vascular epiphytes contribute significantly to the biodiversity of tropical forests. We aimed to identify the epiphyte species occurring in the Muriqui Trail at Serra do Brigadeiro State Park (SBSP), a priority area for Atlantic forest conservation in southeastern Brazil. We selected 10 phorophytes, from which we sampled epiphytes and took light intensity measurements at three strata: up to 4 m, 4 to 8 m, and above 8 m. Phorophytes represented eight species, eight genera, and six families. We found 25 epiphytic species from 17 genera and nine families. Ferns showed highest richness, especially Polypodiaceae. We report herein important data on epiphyte diversity in eastern Minas Gerais state (Zona da Mata), including the occurrence of species rarely cited in surveys. Fomenting local conservation along with environmental education may be pivotal for counteracting anthropic pressure on SBSP.

SUMMARY: The environmental adaptation of eudicots is the most reasonable explanation for why they compose the largest clade of modern plants (>70% of angiosperms), which indicates that the basal eudicots would be valuable and helpful to study their survival and ability to thrive throughout evolutionary processes. Here, we detected two whole‐genome duplication (WGD) events in the high‐quality assembled Akebia trifoliata genome (652.73 Mb) with 24 138 protein‐coding genes based on the evidence of intragenomic and intergenomic collinearity, synonymous substitution rate (KS) values and polyploidization and diploidization traces; these events putatively occurred at 85.15 and 146.43 million years ago (Mya). The integrated analysis of 16 species consisting of eight basal and eight core eudicots further revealed that there was a putative ancient WGD at the early stage of eudicots (temporarily designated θ) at 142.72 Mya, similar to the older WGD of Akebia trifoliata, and a putative core eudicot‐specific WGD (temporarily designated ω). Functional enrichment analysis of retained duplicate genes following the θ event is suggestive of adaptation to the extreme environment change in both the carbon dioxide concentration and desiccation around the Jurassic–Cretaceous boundary, while the retained duplicate genes following the ω event is suggestive of adaptation to the extreme droughts, possibly leading to the rapid spread of eudicots in the mid‐Cretaceous. Collectively, the A. trifoliata genome experienced two WGD events, and the older event may have occurred at the early stage of eudicots, which likely increased plant environmental adaptability and helped them survive in ancient extreme environments. Significance Statement: The genome of Akebia trifoliata, as a representative species of basal eudicots, suggests that a whole genome duplication event occurred at the early stage of eudicots around the Jurassic–Cretaceous boundary and possibly increased ancient eudicots environmental adaptability. [ABSTRACT FROM AUTHOR]

Ancient whole-genome duplications (WGDs) characterize many large angiosperm lineages, including angiosperms themselves. Prominently, the core eudicot lineage accommodates 70% of all angiosperms and shares ancestral hexaploidy, termed gamma. Gamma arose via two WGDs that occurred early in eudicot history; however, the relative timing of these is unclear, largely due to the lack of high-quality genomes among early-diverging eudicots. Here, we provide complete genomes for Buxus sinica (Buxales) and Tetracentron sinense (Trochodendrales), representing the lineages most closely related to core eudicots. We show that Buxus and Tetracentron are both characterized by independent WGDs, resolve relationships among early-diverging eudicots and their respective genomes, and use the RACCROCHE pipeline to reconstruct ancestral genome structure at three key phylogenetic nodes of eudicot diversification. Our reconstructions indicate genome structure remained relatively stable during early eudicot diversification, and reject hypotheses of gamma arising via inter-lineage hybridization between ancestral eudicot lineages, involving, instead, only stem lineage core eudicot ancestors. Gamma triplication arises via two whole-genome duplications early in eudicot history, but the relative timing of these is unclear. Here, the authors report the genomes of Buxales and Trochodendrales and reject the hypothesis of gamma arising via inter-lineage hybridization between ancestral eudicot lineages. [ABSTRACT FROM AUTHOR]

SEPALLATA transcription factors (SEP TFs) have been extensively studied in angiosperms as pivotal components of virtually all the MADS-box tetrameric complex master regulators of floral organ identities. However, there are published reports that suggest that some SEP members also regulate earlier reproductive events, such as inflorescence meristem determinacy and inflorescence architecture, with potential for application in breeding programs in crops. The SEP subfamily underwent a quite complex pattern of duplications during the radiation of the angiosperms. Taking advantage of the many whole genomic sequences now available, we present a revised and expanded SEP phylogeny and link it to the known functions of previously characterized genes. This snapshot supports the evidence that the major SEP3 clade is highly specialized for the specification of the three innermost floral whorls, while its sister LOFSEP clade is functionally more versatile and has been recruited for diverse roles, such as the regulation of extra-floral bract formation and inflorescence determinacy and shape. This larger pool of angiosperm SEP genes confirms previous evidence that their evolution was driven by whole-genome duplications rather than small-scale duplication events. Our work may help to identify those SEP lineages that are the best candidates for the improvement of inflorescence traits, even in far distantly related crops. [ABSTRACT FROM AUTHOR]

Background: Eudicots are the most diverse group of flowering plants that compromise five well-defined lineages: core eudicots, Ranunculales, Proteales, Trochodendrales, and Buxales. However, the phylogenetic relationships between these five lineages and their chromosomal evolutions remain unclear, and a lack of high-quality genome analyses for Buxales has hindered many efforts to address this knowledge gap. Results: Here, we present a high-quality chromosome-level genome of Buxus austro-yunnanensis (Buxales). Our phylogenomic analyses revealed that Buxales and Trochodendrales are genetically similar and classified as sisters. Additionally, both are sisters to the core eudicots, while Ranunculales was found to be the first lineage to diverge from these groups. Incomplete lineage sorting and hybridization were identified as the main contributors to phylogenetic discordance (34.33%) between the lineages. In fact, B. austro-yunnanensis underwent only one whole-genome duplication event, and collinear gene phylogeny analyses suggested that separate independent polyploidizations occurred in the five eudicot lineages. Using representative genomes from these five lineages, we reconstructed the ancestral eudicot karyotype (AEK) and generated a nearly gapless karyotype projection for each eudicot species. Within core eudicots, we recovered one common chromosome fusion event in asterids and malvids, respectively. Further, we also found that the previously reported fused AEKs in Aquilegia (Ranunculales) and Vitis (core eudicots) have different fusion positions, which indicates that these two species have different karyotype evolution histories. Conclusions: Based on our phylogenomic and karyotype evolution analyses, we revealed the likely relationships and evolutionary histories of early eudicots. Ultimately, our study expands genomic resources for early-diverging eudicots. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Diversification of the cellulose synthase superfamily of glycosyltransferases has provided plants with the ability to synthesise varied cell wall polysaccharides such as xyloglucan, mannans and the mixed-linkage glucans of cereals. Surprisingly, some but not all members of the cellulose synthase-like M (CslM) gene family have recently been shown to be involved in the glycosylation of the aglycone core of a range of triterpenoid saponins. However, no cell wall activity has yet been attributed to any of the CslM gene family members. Here, evolution of the CslM gene family in eudicots is explored to better understand the differences between the two metabolically distinct classes of CslMs (CslM1 and CslM2) and the very closely related CslGs. To achieve this, a robust tBLASTn approach was developed to identify CslM1, CslM2 and CslG sequences using diagnostic peptides, suitable for complex genomes using unannotated and short read datasets. To ascertain whether both CslM1 and CslM2 proteins have cell wall functions, in addition to the "saponin" role of CslM2, tomato CslM1 and CslM2 genes were ectopically expressed in Arabidopsis thaliana by stable transformation and in the transient Nicotiana benthamiana system. Transformed plants were analysed with immunofluorescence, immunogold transmission electron microscopy (TEM) and cell wall polysaccharides were extracted for monosaccharide linkage analysis. Our results support a role for both CslM1 and CslM2 in the biosynthesis of type II arabinogalactan linkages generating new insight into how the diverse functions of CslMs can co-exist and providing clear targets for future research., (© The Author(s) 2024. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists.)

Background: Small RNAs (sRNAs) that do not get untranslated into proteins exhibit a pivotal role in the expression regulation of their cognate gene(s) in almost all eukaryotic lineages, including plants. Hitherto, numerous protein families such as Dicer, a unique class of Ribonuclease III, have been reported to be involved in sRNAs processing pathways and silencing. In this study, we aimed to investigate the phylogenetic relationship and evolutionary history of the DCL protein family. Results: Our results illustrated the DCL family of proteins grouped into four main subfamilies (DCLs 1–4) presented in either Eudicotyledons or Liliopsids. The accurate observation of the phylogenetic trees supports the independent expansion of DCL proteins among the Eudicotyledons and Liliopsids species. They share the common origin, and the main duplication events for the formation of the DCL subfamilies occurred before the Eudicotyledons/Liliopsids split from their ancestral DCL. In addition, shreds of evidence revealed that the divergence happened when multicellularization started and since the need for complex gene regulation considered being a necessity by organisms. At that time, they have evolved independently among the monophyletic lineages. The other finding was that the combination of DCL protein subfamilies bears several highly conserved functional domains in plant species that originated from their ancestor architecture. The conservation of these domains happens to be both lineage-specific and inter lineage-specific. Conclusions: DCL subfamilies (i.e., DCL1-DCL4) distribute in their single clades after diverging from their common ancestor and before emerging into higher plants. Therefore, it seems that the main duplication events for the formation of the DCL subfamilies occurred before the Eudicotyledons/Liliopsida split and before the appearance of moss, and after the single-cell green algae. We also observed the same trends among the main DCL subfamilies from functional unit composition and architecture. Despite the long evolutionary course from the divergence of Liliopsida lineage from the Eudicotyledons, a significant diversifying force to domain composition and orientation was absent. The results of this study provide a deeper insight into DCL protein evolutionary history and possible sequence and structural relationships between DCL protein subfamilies in the main higher plant monophyletic lineages; i.e., Eudicotyledons and Liliopsida. [ABSTRACT FROM AUTHOR]

This study was conducted for extensive and systemic investigation of anatomical, palynological and seed morphological properties of two endemic Noccaea species, naturally growing in Turkey. Independent sample T-test and box plot were carried out using quantitative characters of the studied species. The anatomical results showed that the species had similar characteristics, though there were significant differences in root cortex cells and trachea; stem epidermis, cortex cell and endodermis; leaf upper and lower epidermis, lower cuticle, mesophyll and palisade parenchyma. Pollen grains of two endemic species were observed as radially symmetric, isopolar, with tricolpate aperture, prolate pollen shape and had small size. Pollen surface ornamentation was micro-reticulate in both species. Considering palynological characters, equatorial axis, AMB exine and intine have taxonomic importance. Seeds of N. birolmutlui were ovate to orbicular in shape and orange-brown in color, with colliculate ornamentation; however, the seeds of N. camlikensis were ovate to oblong in shape and brown and shiny in color, with colliculate-reticulate ornamentation. [ABSTRACT FROM AUTHOR]

The early diversification of angiosperms is thought to have been a rapid process, which may complicate phylogenetic analyses of early angiosperm relationships. Plastid and nuclear phylogenomic studies have raised several conflicting hypotheses regarding overall angiosperm phylogeny, but mitochondrial genomes have been largely ignored as a relevant source of information. Here we sequenced mitochondrial genomes from 18 angiosperms to fill taxon‐sampling gaps in Austrobaileyales, magnoliids, Chloranthales, Ceratophyllales, and major lineages of eudicots and monocots. We assembled a data matrix of 38 mitochondrial genes from 107 taxa to assess how well mitochondrial genomic data address current uncertainties in angiosperm relationships. Although we recovered conflicting phylogenies based on different data sets and analytical methods, we also observed congruence regarding deep relationships of several major angiosperm lineages: Chloranthales were always inferred to be the sister group of Ceratophyllales, Austrobaileyales to mesangiosperms, and the unplaced Dilleniales was consistently resolved as the sister to superasterids. Substitutional saturation, GC compositional heterogeneity, and codon‐usage bias are possible reasons for the noise/conflict that may impact phylogenetic reconstruction; and angiosperm mitochondrial genes may not be substantially affected by these factors. The third codon positions of the mitochondrial genes appear to contain more parsimony‐informative sites than the first and second codon positions, and therefore produced better resolved phylogenetic relationships with generally strong support. The relationships among these major lineages remain incompletely resolved, perhaps as a result of the rapidity of early radiations. Nevertheless, data from mitochondrial genomes provide additional evidence and alternative hypotheses for exploring the early evolution and diversification of the angiosperms. [ABSTRACT FROM AUTHOR]

Opuntia macrorhiza (Cactaceae) was first found in Turkey in 2020 during floristic surveys in the Boyabat district of the Sinop province and in the Cide district of the Kastamonu province. We provide an identification key to distinguish it from Opuntia ficus-indica, a morphological description, as well as some basic information on invaded habitat and potential threats. Considering the traits of this new alien plant, allowing for rapid reproduction, and spread, it is expected it might invade further land without adequate interventions. [ABSTRACT FROM AUTHOR]

KINETOCHORE NULL2 (KNL2) plays key role in the recognition of centromeres and new CENH3 deposition. To gain insight into the origin and diversification of the KNL2 gene, we reconstructed its evolutionary history in the plant kingdom. Our results indicate that the KNL2 gene in plants underwent three independent ancient duplications in ferns, grasses, and eudicots. Additionally, we demonstrated that previously unclassified KNL2 genes could be divided into two clades αKNL2 and βKNL2 in eudicots and γKNL2 and δKNL2 in grasses, respectively. KNL2 s of all clades encode the conserved SANTA domain, but only the αKNL2 and γKNL2 groups additionally encode the CENPC-k motif. In the more numerous eudicot sequences, signatures of positive selection were found in both αKNL2 and βKNL2 clades, suggesting recent or ongoing adaptation. The confirmed centromeric localization of βKNL2 and mutant analysis suggests that it participates in loading of new CENH3, similarly to αKNL2. A high rate of seed abortion was found in heterozygous βknl2 plants and the germinated homozygous mutants did not develop beyond the seedling stage. Taken together, our study provides a new understanding of the evolutionary diversification of the plant kinetochore assembly gene KNL2 , and suggests that the plant-specific duplicated KNL2 genes are involved in centromere and/or kinetochore assembly for preserving genome stability. [ABSTRACT FROM AUTHOR]

Eudicots account for ~75% of living angiosperms, containing important food and energy crops. Recently, high-quality genome sequences of several eudicots including Aquilegia coerulea and Nelumbo nucifera have become available, providing an opportunity to investigate the early evolutionary characteristics of eudicots. We performed genomic hierarchical and event-related alignments to infer homology within and between representative species of eudicots. The results provide strong evidence for multiple independent polyploidization events during the early diversification of eudicots, three of which are likely to be allopolyploids: The core eudicot-common hexaploidy (ECH), Nelumbo -specific tetraploidy (NST), and Ranunculales-common tetraploidy (RCT). Using different genomes as references, we constructed genomic alignment to list the orthologous and paralogous genes produced by polyploidization and speciation. This could provide a fundamental framework for studying other eudicot genomes and gene(s) evolution. Further, we revealed significantly divergent evolutionary rates among these species. By performing evolutionary rate correction, we dated RCT to be ~118–134 million years ago (Mya), after Ranunculales diverged with core eudicots at ~123–139 Mya. Moreover, we characterized genomic fractionation resulting from gene loss and retention after polyploidizations. Notably, we revealed a high degree of divergence between subgenomes. In particular, synonymous nucleotide substitutions at synonymous sites (Ks) and phylogenomic analyses implied that A. coerulea might provide the subgenome(s) for the gamma -hexaploid hybridization. [ABSTRACT FROM AUTHOR]

Summary: Organisation and patterning of the vascular network in land plants varies in different taxonomic, developmental and environmental contexts. In leaves, the degree of vascular strand connectivity influences both light and CO2 harvesting capabilities as well as hydraulic capacity. As such, developmental mechanisms that regulate leaf venation patterning have a direct impact on physiological performance. Development of the leaf venation network requires the specification of procambial cells within the ground meristem of the primordium and subsequent proliferation and differentiation of the procambial lineage to form vascular strands. An understanding of how diverse venation patterns are manifest therefore requires mechanistic insight into how procambium is dynamically specified in a growing leaf. A role for auxin in this process was identified many years ago, but questions remain. In this review we first provide an overview of the diverse venation patterns that exist in land plants, providing an evolutionary perspective. We then focus on the developmental regulation of leaf venation patterns in angiosperms, comparing patterning in eudicots and monocots, and the role of auxin in each case. Although common themes emerge, we conclude that the developmental mechanisms elucidated in eudicots are unlikely to fully explain how parallel venation patterns in monocot leaves are elaborated. [ABSTRACT FROM AUTHOR]

Shrirangia, a new monotypic genus of the family Apiaceae from low elevated lateritic plateaus of south Konkan region of Maharashtra, India is described and illustrated with a new species, Shrirangia concanensis. The new genus is related to Himalayan genus Chamaesium H.Wolff by the characters of: many (ca 10) ribbed fruit, primary and secondary types of ribs present but very distinct from it by having tuberous habit, ternate to bi‐ternate leaves, commissure plain undulate with 6–7 secondary ribs and vallecular and second types of vittae at dorsal face. [ABSTRACT FROM AUTHOR]

Evidence have indicated that RR-type MYB-related transcription factors (TFs) are functionally diverse in regulating floral development, fruit development, leaf senescence, ABA response, and drought and salt responses. Several RR-type MYB-related TFs in Arabidopsis, Antirrhinum and rice are identified and characterized. However, the complete RR-type MYB-related family in tomato has not been studied to date. Here, a genome-wide identification of tomato RR-type MYB-related TFs (SlMYBR) was performed by bioinformatics analysis, and their expression patterns were analyzed. A total of thirteen SlMYBR genes, which were mainly distributed in the head or tail of the chromosome, were identified from tomato and were divided into three groups. Group II was all MYBR genes from eudicots without genes from monocots. For Group I and Group III, the phylogenetic tree was in accord with the evolutionary relationship of these species. SlMYBR proteins were unstable proteins and located in the nucleus. The promoters of SlMYBR contained multiple important cis-acting elements related to abiotic stress or hormone responses. SlMYBR genes had various temporal and spatial expression patterns. Experiments of spraying exogenous hormone demonstrated that the expression of most genes containing hormone response elements was changed, indicating that the expression patterns were associated with the amount of cis-acting elements. The comprehensive investigation of tomato SlMYBR genes in the present study helps to clearly understand the evolution of RR-type MYB-related TFs and provides a useful reference for the further functional study of SlMYBR genes in tomato. [ABSTRACT FROM AUTHOR]

Transposable elements (TEs) constitute a major threat to genome stability and are therefore typically silenced by epigenetic mechanisms. In response, some TEs have evolved counteracting systems to suppress epigenetic silencing. In the model plant Arabidopsis thaliana, two such anti‐silencing systems have been identified and found to be mediated by the VANC DNA‐binding proteins encoded by VANDAL transposons. Here, we show that anti‐silencing systems have rapidly diversified since their origin in eudicots by gaining and losing VANC‐containing domains, such as DUF1985, DUF287, and Ulp1, as well as target sequence motifs. We further demonstrate that these motifs determine anti‐silencing specificity by sequence, density, and helical periodicity. Moreover, such rapid diversification yielded at least 10 distinct VANC‐induced anti‐silencing systems in Arabidopsis. Strikingly, anti‐silencing of non‐autonomous VANDALs, which can act as reservoirs of 24‐nt small RNAs, is critical to prevent the demise of cognate autonomous TEs and to ensure their propagation. Our findings illustrate how complex co‐evolutionary dynamics between TEs and host suppression pathways have shaped the emergence of new epigenetic control mechanisms. Synopsis: Transposable elements (TEs) can escape their typical fate of epigenetic silencing through still poorly‐understood mechanisms. Systematic characterization of VANDAL transposon‐encoded anti‐silencing systems in A. thaliana sheds light on the co‐evolutionary dynamics that lead to novel epigenetic control mechanisms. VANDAL‐encoded VANC anti‐silencing proteins paredate the radiation of eudicots and exhibit rapid diversification through gain/loss of domains and target short‐sequence motifs.Sequence, density, and helical periodicity of motifs within non‐coding regions of VANDALs determine VANC targeting.Non‐autonomous VANDAL elements hijack the anti‐silencing mechanisms of related autonomous VANDALs to promote their own hypomethylation.Loss of target motifs within non‐autonomous elements can induce concerted epigenetic re‐silencing of related VANDALs, potentially self‐limiting runaway transposon proliferation. [ABSTRACT FROM AUTHOR]