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Cotinus is an oligo-specific ornamentally valuable genus with a disjunct distribution in the Northern Hemisphere. Traditionally, the taxonomy of Cotinus was mainly based on leaf morphological characteristics. However, the limited availability of genomic information greatly hindered the study of molecular evolution and phylogeny of this genus. This study sequenced the chloroplast (cp) genomes of all currently recognized taxa of Cotinus , including three species and four varieties. A comparative analysis was performed to investigate their cp genome characteristics and evolution. Furthermore, we inferred the phylogenetic relationships of Cotinus based on whole cp genomes, protein-coding genes, and nuclear ITS data. All cp genomes exhibited a typical quadripartite structure with genome sizes ranging from 158,865 to 160,155 bp. A total of 113-114 genes were identified in the genomes. Seven non-coding and four coding regions were identified as the most divergent hotspots for potential molecular barcodes and phylogenetic markers. Selection pressure analysis showed that there had been positive selection on genes matK and rps8 in the Cotinus cp genomes. Phylogenetic results confirmed that Cotinus is a monophyletic group but the widely distributed species Cotinus coggygria is not monophyletic. The divergence-time analysis suggested that Cotinus underwent an evolutionary divergence from the middle Eocene and rapid adaptive radiation from the middle Miocene. This study revealed new insights into the cp genome evolution and phylogeny of Cotinus and related taxa., Competing Interests: The authors declare that there is no conflict of interest., (© 2023 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)

Rutaceae is a large family, and the genus-level classification in the subfamilies or tribes of this family is not unified based on different taxonomic treatments. Until now, phylogenetic relationships of some genera in traditional tribe Ruteae have not been clearly resolved. In this study, seven new complete plastomes of this tribe were sequenced, and a comparative analysis was performed to investigate their plastome characteristics and evolution. In addition, we inferred the phylogenetic relationships of Ruteae based on complete plastome and nuclear ITS data. All plastomes exhibited a typical quadripartite structure and were relatively conserved in their structure and gene arrangement. Their genome sizes ranged from 154,656 bp to 160,677 bp, and the size variation was found to be associated with differences in IR expansion and gene loss. A total of 112 to 114 genes were identified in the genomes, including 78 to 79 protein-coding genes, 30 tRNA genes, 4 rRNA genes, and 2 pseudogenes. Sequence divergence analysis indicated that non-coding regions exhibited a higher percentage of variable characters, and nine non-coding and six coding regions were identified as divergent hotspots. Phylogenetic results based on different datasets showed that this tribe was divided into three reciprocally exclusive groups. The phylogenetic analyses between plastome and nuclear ITS data were partly incongruent with each other. This study provides new insights into plastome evolution of Ruteae as well as Rutaceae. The availability of these plastomes provides useful genomic resources for molecular DNA barcodes and phylogenetically informative markers and deepens our understanding of the phylogeny in Ruteae., Competing Interests: The authors declare that there is no conflict of interest., (© 2023 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)

Main Conclusion: This study compared the plastomes of Ulmaceae allowing analyses of the dynamic evolution, including genome structure, codon usage bias, repeat sequences, molecular mutation rates, and phylogenetic inferences. Ulmaceae is a small family in the order Rosales. This family consists of seven genera, including Ulmus, Zelkova, Planera, Hemiptelea, Phyllostylon, Ampelocera, and Holoptelea. Ulmaceae is an interesting lineage from plant biogeographic, systematic, evolutionary, and paleobotanic perspectives. It is also a good model to investigate the evolution of the plastomes in woody plants. In this study, we sequenced and assembled the complete plastomes of the six Ulmaceae genera to compare genomic structures and reveal the molecular evolutionary patterns. The size of the quadripartite plastomes ranged from 158,290 bp to 161,886 bp. The genomes contained 131 genes, including 87 coding genes, 36 tRNA, and 8 rRNA. The gene number, gene content, and genomic structure were highly consistent among the Ulmaceae genera. Nine variable regions including ndhA intron, ndhF-rpl32, ycf1, psbK-trnS, rps16-trnQ, trnT-trnL, trnT-psbD, trnS-trnG, and rpl32-trnL, were identified in Ulmaceae plastomes according to the nucleotide diversity values. Condon usage was biased among the genes and showed consistent trends in the seven genera. Molecular evolution analyses revealed that most of the genes and all gene groups were under widespread purifying selection. Twelve genes (ccsA, matK, psbH, psbK, rbcL, rpl22, rpl32, rpoA, rps12, rps15, rps16, and ycf2) were under positive selection. Phylogenetic analyses supported that Ulmaceae should be divided into two main clades, such as the temperate clade, including Ulmus, Zelkova, Planera, and Hemiptelea and the tropical clade, including Phyllostylon, Ampelocera and Holoptelea. This study reports the structure and evolutionary characteristics of the Elm family. These new genomic data will benefit assessments of genomic evolution and provide information to elucidate the phylogenetic relationships among Ulmaceae species., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Acer leipoense is a rare and endangered species of the Sapindaceae with a very restricted distribution in Sichuan, China. In this study, the complete chloroplast genome of A. leipoense was characterized by de novo assembly using high-throughput sequencing. The chloroplast genome was 155,702 bp in length; it contained a large single copy region (85,890 bp) and a small single copy region (18,100 bp), which were separated by a pair of 25,856-bp inverted repeat regions. A total of 128 genes were predicted, including 83 protein-coding genes, 37 tRNA genes, and eight rRNA genes. A phylogenetic analysis of 23 chloroplast genome sequences from the genus Acer revealed that A. leipoense was closely related to A. yangbiense ., Competing Interests: The authors declare there is no conflicts of interest and are responsible for the content., (© 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)

Existing methods can not achieve rapid mass decomposition and multi-element analysis of graphite ore samples. In this study, it is found that molten lithium metaborate can destroy the structure of graphite, causing graphite C to be oxidized and decomposed in an oxygen environment. We have established a method for testing graphite ore samples with lithium metaborate at 950°C with melting-ultrasonic extraction-ICP-AES multi-element (Al, Ca, Fe, K, Mg, Mn, Na, P, Si, and Ti) testing. The verification results of the national first-level reference materials show that the detection limit of this method is low and the accuracy and precision are good. The results of the measured samples show no significant difference between this method and the classical chemical analysis method. This method has the following advantages over the existing ones: simple operation process, faster decomposition and testing, low reagent consumption, reduced possibility of sample contamination, and better results reproducibility.

Phellodendron chinense is an Endangered medicinal plant in southern China. In this study, the complete chloroplast genome sequence of P.chinense was characterized by de novo assembly. The length of the whole chloroplast genome was 158,537 bp, containing a large single copy region (LSC) of 86,250 bp and a small single copy region (SSC) of 18,287 bp, which were separated by a pair of 27,000 bp inverted repeat regions (IRs). The sequence contains 114 unique genes, including 30 tRNA, 4 rRNA, and 80 protein-coding genes. The overall GC content of the chloroplast genome is 38.4% and those in the LSC, SSC, and IR regions are 36.6, 33.2, and 42.9%, respectively. The phylogenetic analysis based on reported chloroplast sequences of Rutaceae showed that P. chinense is sister to P. amurense , consisting a monophyletic group, and that Phellodendron is closely related to Zanthoxylum ., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2020 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)

Background: Elaiosomes are specialized fleshy and edible seed appendages dispersed by ants. Lipids are the primary components of elaiosomes. Chelidonium majus is a well-known plant, the seeds of which are dispersed by ants. Previous studies have identified the presence of primary fatty acids in its elaiosomes and seeds. However, the molecular mechanisms underlying fatty acid biosynthesis in elaiosomes remain unknown., Methods: In order to gain a comprehensive transcriptional profile of the elaiosomes and seeds of C. majus , and understand the expression patterns of genes associated with fatty acid biosynthesis, four different developmental stages, including the flower-bud (Ch01), flowering (Ch02), young seed (Ch03), and mature seed (Ch04) stages, were chosen to perform whole-transcriptome profiling through the RNA-seq technology (Illumina NGS sequencing)., Results: A total of 63,064 unigenes were generated from 12 libraries. Of these, 7,323, 258, and 11,540 unigenes were annotated with 25 Cluster of Orthologous Groups, 43 Gene Ontology terms, and 373 Kyoto Encyclopedia of Genes and Genomes pathways, respectively. In addition, 322 genes were involved in lipid transport and metabolism, and 508 genes were involved in the lipid metabolism pathways. A total of 41 significantly differentially expressed genes (DEGs) involved in the lipid metabolism pathways were identified, most of which were upregulated in Ch03 compared to Ch02, indicating that fatty acid biosynthesis primarily occurs during the flowering to the young seed stages. Of the DEGs, acyl-ACP thioesterases, acyl carrier protein desaturase ( DESA1 ), and malonyl CoA-ACP transacylase were involved in palmitic acid synthesis; stearoyl-CoA desaturase and DESA1 were involved in oleic acid synthesis, and acyl-lipid omega-6 desaturase was involved in linoleic acid synthesis., Competing Interests: The authors declare that they have no competing interests.

The seeds of Salix and Populus (Salicaceae) are characterized by having numerous long hairs which loosely accompanying the seeds and a small annular appendage which surrounding the base of the seed along with tufted hairs. In this study, the complete development and detailed structure of the hairs and annular appendage in Salix matsudana were investigated using standard techniques for plant anatomy and histochemistry. The results show that the hairs originate successively from the single epidermal cells of the placenta (in megaspore mother cell phase) and funiculus (in eight-nucleate phase), and that their development consists of a progressive increase in cell size and an absence of cell division. The annular appendage is initiated from four to five rows of cells at the distal end of the funiculus in octant proembryo phase and its development is characterized by reactivated meristematic activity and a size increase of these cells. The initiation and development of the hairs are irrelevant to ovule development but fertilization and a developed embryo is necessary for the annular appendage to occur. Considering the reliable fossils, we inferred that the feature of seeds surrounded by long hairs is an ancestral character, and that the detachment of hairs from the funiculus and the occurrence of an annular appendage with tufts of hairs may be the more derived states for seed dispersal in Salix and Populus., Competing Interests: The authors have declared that no competing interests exist.