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Performance Profiles of Short DNA Barcode Segments for Family Level Detection of Asteraceae Within Asterales.

Short DNA barcodes may facilitate sequence recovery from degraded material, but their ability to retain target-family identity while excluding related taxa varies among genomic regions. We computationally evaluated 16 nuclear, plastid, and mitochondrial marker regions from 11 Asterales families using 279,956 NCBI locus-record matches and an accession-disjoint discovery/test design. Thirty-one candidate segments of 50-200 bp (mean, 98.55 bp) were screened in discovery data and evaluated for within-Asteraceae sequence recall, differentiation from non-Asteraceae Asterales, in silico primer behavior, phylogenetic placement, and exploratory matching across 808 metadata-defined metagenomic samples. Conserved regions such as matR and rbcL showed high within-Asteraceae identity, whereas ITS1, ITS, and trnH-psbA showed larger differences from related-family backgrounds; ITS2 and ycf1 showed intermediate profiles. Candidate segments were placed within or immediately adjacent to Asteraceae reference branches in segment-specific maximum-likelihood analyses, although support and topology varied among regions. Metadata-defined target-containing groups had higher mean query coverage and identity than background groups; because target presence was not independently verified and no classifier was fitted, these comparisons were descriptive and did not estimate diagnostic accuracy. Definitionally linked sequence statistics were interpreted as structural associations rather than evidence of causal evolutionary mechanisms. These results provide a family-level computational comparison of candidate short segments for Asteraceae detection within Asterales. Species identification, operational marker combinations, threshold robustness, and laboratory performance require validation using taxonomically dense, voucher-linked, and experimentally characterized datasets.

Asteraceae↗

The genome sequence of Gnaphalium uliginosum L., 1753 (Asterales: Asteraceae).

We present a genome assembly of Gnaphalium uliginosum (marsh cudweed; Streptophyta; Magnoliopsida; Asterales; Asteraceae). The genome sequence has a total length of 354.38 megabases. Most of the assembly (98.86%) is scaffolded into 7 chromosomal pseudomolecules. The mitochondrial sequence has a length of 195.0 kilobases and the plastid genome assembly has a length of 152.8 kilobases. Gene annotation of this assembly on Ensembl identified 24 149 protein-coding genes. This assembly was generated as part of the Darwin Tree of Life project, which produces reference genomes for eukaryotic species found in Britain and Ireland.

Asterales↗

The genome sequence of Filago lutescens Jord., 1846 (Asterales: Asteraceae).

We present a genome assembly of Filago lutescens (Red-tipped Cudweed; Streptophyta; Magnoliopsida; Asterales; Asteraceae). The assembly consists of two haplotypes with total lengths of 648.45 megabases and 646.22 megabases. Most of haplotype 1 (99.77%) is scaffolded into 14 chromosomal pseudomolecules. Haplotype 2 was assembled to scaffold level. The mitochondrial sequence has a length of 225.84 kilobases and the plastid genome assembly has a length of 151.54 kilobases. Gene annotation of this assembly on Ensembl identified 38 942 protein-coding genes. This assembly was generated as part of the Darwin Tree of Life project, which produces reference genomes for eukaryotic species found in Britain and Ireland.

Asterales↗

Structural analysis of xyloglucans in the primary cell walls of plants in the subclass Asteridae.

The structures of xyloglucans from several plants in the subclass Asteridae were examined to determine how their structures vary in different taxonomic orders. Xyloglucans, solubilized from plant cell walls by a sequential (enzymatic and chemical) extraction procedure, were isolated, and their structures were characterized by NMR spectroscopy and mass spectrometry. All campanulids examined, including Lactuca sativa (lettuce, order Asterales), Tenacetum ptarmiciflorum (dusty miller, order Asterales), and Daucus carota (carrot, order Apiales), produce typical xyloglucans that have an XXXG-type branching pattern and contain alpha-d-Xylp-, beta-D-Galp-(1-->2)-alpha-D-Xylp-, and alpha-L-Fucp-(1-->2)-beta-D-Galp-(1-->2)-alpha-D-Xylp- side chains. However, the lamiids produce atypical xyloglucans. For example, previous analyses showed that Capsicum annum (pepper) and Lycopersicon esculentum (tomato), two species in the order Solanales, and Olea europaea (olive, order Lamiales) produce xyloglucans that contain arabinosyl and galactosyl residues, but lack fucosyl residues. The XXGG-type xyloglucans produced by Solanaceous species are less branched than the XXXG-type xyloglucan produced by Olea europaea. This study shows that Ipomoea pupurea (morning glory, order Solanales), Ocimum basilicum (basil, order Lamiales), and Plantago major (plantain, order Lamiales) all produce xyloglucans that lack fucosyl residues and have an unusual XXGGG-type branching pattern in which the basic repeating core contains five glucose subunits in the backbone. Furthermore, Neruim oleander (order Gentianales) produces an XXXG-type xyloglucan that contains arabinosyl, galactosyl, and fucosyl residues. The appearance of this intermediate xyloglucan structure in oleander has implications regarding the evolutionary development of xyloglucan structure and its role in primary plant cell walls.

Alcohols↗

The phylogeny of the Asteridae sensu lato based on chloroplast ndhF gene sequences.

A phylogenetic study of Asteridae sensu lato was conducted based on chloroplast ndhF gene sequences for 116 ingroup and 13 outgroup species. Prior molecular studies based on rbcL sequences identified terminal groups corresponding to families, but were unable to resolve relationships among them. These results are largely consistent with earlier rbcL studies, but provide much greater resolution and stronger bootstrap support throughout the tree. The parsimony analysis found eight equally parsimonious trees, all of which recognize four major clades with the following relationship: (Cornales (Ericales (Euasterids I, Euasterids II))). Euasterids I includes (Garryales ((Solanales, Boraginaceae) (Gentianales, Lamiales))), although with weak support for relationships among the named clades. Euasterids II includes (Aquifoliales (Asterales (Apiales, Dipsacales))) with strong support for these relationships. Relationships within Ericales are weakly supported and merit further attention.

DNA, Chloroplast↗

Inter-taxa differences in root uptake of 103/106Ru by plants.

Ruthenium-106 is of potential radioecological importance but soil-to-plant Transfer Factors for it are available only for few plant species. A Residual Maximum Likelihood (REML) procedure was used to construct a database of relative (103/106)Ru concentrations in 114 species of flowering plants including 106 species from experiments and 12 species from the literature (with 4 species in both). An Analysis of Variance (ANOVA), coded using a recent phylogeny for flowering plants, was used to identify a significant phylogenetic effect on relative mean (103/106)Ru concentrations in flowering plants. There were differences of 2,465-fold in the concentration to which plant species took up (103/106)Ru. Thirty-nine percent of the variance in inter-species differences could be ascribed to the taxonomic level of Order or above. Plants in the Orders Geraniales and Asterales had notably high uptake of (103/106)Ru compared to other plant groups. Plants on the Commelinoid monocot clades, and especially the Poaceae, had notably low uptake of (103/106)Ru. These data demonstrate that plant species are not independent units for (103/106)Ru concentrations but are linked through phylogeny. It is concluded that models of soil-to-plant transfer of (103/106)Ru should assume that; neither soil variables alone affect transfer nor plant species are independent units, and taking account of plant phylogeny might aid predictions of soil-to-plant transfer of (103/106)Ru, especially for species for which Transfer Factors are not available.

Analysis of Variance↗

Phylogenetics of asterids based on 3 coding and 3 non-coding chloroplast DNA markers and the utility of non-coding DNA at higher taxonomic levels.

Asterids comprise 1/4-1/3 of all flowering plants and are classified in 10 orders and >100 families. The phylogeny of asterids is here explored with jackknife parsimony analysis of chloroplast DNA from 132 genera representing 103 families and all higher groups of asterids. Six different markers were used, three of the markers represent protein coding genes, rbcL, ndhF, and matK, and three other represent non-coding DNA; a region including trnL exons and the intron and intergenic spacers between trnT (UGU) to trnF (GAA); another region including trnV exons and intron, trnM and intergenic spacers between trnV (UAC) and atpE, and the rps16 intron. The three non-coding markers proved almost equally useful as the three coding genes in phylogenetic reconstruction at the high level of orders and families in asterids, and in relation to the number of aligned positions the non-coding markers were even more effective. Basal interrelationships among Cornales, Ericales, lamiids (new name replacing euasterids I), and campanulids (new name replacing euasterids II) are resolved with strong support. Family interrelationships are fully or almost fully resolved with medium to strong support in Cornales, Garryales, Gentianales, Solanales, Aquifoliales, Apiales, and Dipsacales. Within the three large orders Ericales, Lamiales, and Asterales, family interrelationships remain partly unclear. The analysis has contributed to reclassification of several families, e.g., Tetrameristaceae, Ebenaceae, Styracaceae, Montiniaceae, Orobanchaceae, and Scrophulariaceae (by inclusion of Pellicieraceae, Lissocarpaceae, Halesiaceae, Kaliphoraceae, Cyclocheilaceae, and Myoporaceae+Buddlejaceae, respectively), and to the placement of families that were unplaced in the APG-system, e.g., Sladeniaceae, Pentaphylacaceae, Plocospermataceae, Cardiopteridaceae, and Adoxaceae (in Ericales, Ericales, Lamiales, Aquifoliales, and Dipsacales, respectively), and Paracryphiaceae among campanulids. Several families of euasterids remain unclassified to order.

Chloroplasts↗

Phylogenetic analysis of the "ECE" (CYC/TB1) clade reveals duplications predating the core eudicots.

Flower symmetry is of special interest in understanding angiosperm evolution and ecology. Evidence from the Antirrhineae (snapdragon and relatives) indicates that several TCP gene-family transcription factors, especially CYCLOIDEA (CYC) and DICHOTOMA (DICH), play a role in specifying dorsal identity in the corolla and androecium of monosymmetric (bilateral) flowers. Studies of rosid and asterid angiosperms suggest that orthologous TCP genes may be important in dorsal identity, but there has been no broad phylogenetic context to determine copy number or orthology. Here, we compare published data from rosids and asterids with newly collected data from ranunculids, caryophyllids, Saxifragales, and Asterales to ascertain the phylogenetic placement of major duplications in the "ECE" (CYC/TB1) clade of TCP transcription factors. Bayesian analyses indicate that there are three major copies of "CYC" in the ECE clade, and that duplications leading to these copies predate the core eudicots. CYC1 contains no subsequent duplications and may not be expressed in floral tissue. CYC3 exhibits similar patterns of duplication to CYC2 in several groups. Using RT-PCR, we show that, in flowers of Lonicera morrowii (Caprifoliaceae), DipsCYC2B is expressed in the four dorsal petals and not in the ventral petal. DipsCYC3B is expressed in flower and petal primordia, possibly most strongly in the ventral petal.

Antirrhinum↗

Acaricidal activity of aqueous extracts of camomile flowers, Matricaria chamomilla, against the mite Psoroptes cuniculi.

Arcaricidal properties of decoctions, infusions and macerates of dried flower heads of camomile, Matricaria chamomilla L. (Asterales: Asteraceae) were tested in vitro against the mite Psoroptes cuniculi Delafond (Parasitiformes: Psoroptidae). This mite species is responsible for otoacariasis in domestic animals. Mites were exposed to the extracts for 24, 48 or 72 h. All the extracts tested showed highly significant acaricidal activity when compared with controls. Among them, a decoction of 10% was the only formulation which gave 100% activity at all the three observations times.

Animals↗

Predicting inter-taxa differences in plant uptake of cesium-134/137.

For (134/137)Cs, and many other soil contaminants, research into transfer to plants has focused on particular crops and phytoremediation candidates, producing uptake data for a small proportion of all plant taxa. Despite the significance of differences in uptake between plant taxa, the capacity of soil-to-plant transfer models to predict them is currently confined to those taxa for which data exist, there being no method to predict uptake by other taxa. We used residual maximum likelihood (REML) analysis on data from experiments (including 89 plant taxa from China plus 32 phytoremediation candidates) together with data from the literature, to construct a database of relative (134/137)Cs concentrations in 273 plant taxa. The REML (134/137)Cs concentrations in plants are not normally distributed but significantly clustered. Analysis of variance (ANOVA), coded with a recent ordinal phylogeny for flowering plants, showed that plant taxa do not behave independently for (134/137)Cs concentration because 42 and 15% of inter-taxa differences are associated with phylogeny above the species and ordinal level, respectively. In general, Eudicots, and especially the Caryophyllales, Asterales, and Brassicales, have high (134/137)Cs concentrations, while the Fabales and Magnoliids, in particular Poales, have low (134/137)Cs concentrations. Plants of the stress-tolerant ruderal (S-R) growth strategy sensu Grime have, in general, high concentrations of Cs, while those of the competitive (C) and generalist (C-S-R) strategies have low concentrations, although these effects are less pronounced than those of phylogeny. Plant phylogeny and growth strategy might thus be used to predict a significant portion of inter-taxa differences in plant uptake of (134/137)Cs.

Adaptation, Physiological↗

The genome sequence of Veronica verna L., 1753 (Lamiales: Plantaginaceae).

We present a genome assembly of Veronica verna (Spring Speedwell; Streptophyta; Magnoliopsida; Lamiales; Plantaginaceae). The genome sequence has a total length of 463.88 megabases. Most of the assembly (98.85%) is scaffolded into 8 chromosomal pseudomolecules. The mitochondrial sequence has a length of 311.81 kilobases and the plastid genome assembly has a length of 149.82 kilobases. Gene annotation of this assembly on Ensembl identified 22 903 protein-coding genes. This assembly was generated as part of the Darwin Tree of Life project, which produces reference genomes for eukaryotic species found in Britain and Ireland.

Asterales↗