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Many species of the subfamily Polygonoideae are economically important. However, phylogenetic relationships and taxonomic treatments of these species remain disputed. In this study, we used highly orthologous nuclear genes and plastome sequence variation extracted from transcriptomes from 98 species of 26 genera of Polygonaceae mainly from the subfamily Polygonoideae to construct a robust phylogeny. We discerned six successively diverged and well‐defined clades and both nuclear and plastome phylogenies are highly consistent with each other in this subfamily. Phylogenetic relationships between all clades and subclades were well resolved within Polygonoideae. Our analyses revealed that the shrub tribe Atraphaxideae and the herbal genera Polygonum, Persicaria, and Fallopia are polyphyletic. The sampled species of Polygonoideae started to diversify around the Cretaceous/Tertiary boundary (70 Ma) when the global climate exhibited large oscillations. Further origins of more herbal and woody species were found to have clearly increased during later climatic oscillations. We found that woody habits, especially shrubs, originated multiple times from ancestral herbs in this subfamily. Local dry climates may have favored such habit shifts from ancestral herbs. Our results deepen our understanding of evolutionary diversification of Polygonoideae. [ABSTRACT FROM AUTHOR]

Both geographic isolation and polyploidization are assumed to play an important role in driving species diversification. However, this is rarely illustrated through phylogenomic analyses. The genus Eutrema (Brassicaceae), which also includes the salt‐resistant species, are distributed mainly in Asia with extensive species diversification in the Qinghai–Tibet Plateau (QTP) and adjacent regions. In this study, we revealed almost fully resolved backbone relationships of the genus with genome re‐sequencing data for genomes of 168 individuals from 28 species. Phylogenetic analyses of both plastomes and single‐copy nuclear genes from the whole genome recovered six well‐supported clades with almost consistent relationships. The first two clades are mainly distributed in central China and central Asia, while the other four in the QTP and adjacent regions. All of them diversified within 12 million years. Within each clade, we recovered numerous conflicts in the interspecific relationships between nuclear and plastome phylogenies, likely suggesting hybridization and incomplete lineage sorting during species diversification. Our estimation of genome size and comparison of the number of the single‐copy nuclear genes demonstrated frequent occurrences of polyploids in the genus. Except for an establishment of the backbone phylogeny, our phylogenomic analyses suggest that in addition to strong geographic isolation, polyploidization may have played an important role in species diversification of this genus. [ABSTRACT FROM AUTHOR]

The development of next‐generation sequencing technologies allows researchers to address complex problems in species delimitation, especially for non‐model organisms. The taxonomic status of North American Nyssa species has long been debated and remains controversial. To elucidate the genetic structure and phylogenetic relationships of the five currently recognized North American Nyssa species, we conducted whole‐genome sequencing of representative individuals and identified genome‐wide single‐nucleotide polymorphisms (SNPs) by utilizing the recently released chromosome‐level assembly of Nyssa sinensis genome. Population genetic and phylogenetic analyses consistently inferred four well‐supported genetic clusters from our sampled individuals, that is, N. aquatica, N. ogeche, N. sylvatica, and N. biflora–N. ursina. Although the identification of N. biflora and N. ursina is primarily based on the morphological characteristics of leaves and drupes, the present evidence, including our principal components analysis of leaf morphological traits, strongly supports the taxonomic designation of N. biflora and N. ursina as a single species. In addition, these four genetic clusters were grouped into two major clades, that is, clade 1 (N. aquatica and N. ogeche) and clade 2 (N. sylvatica and N. biflora–N. ursina). Despite the fact that no evidence of widespread gene flow was found between these two major clades, our analyses revealed the possibility of introgression from N. sylvatica into N. biflora, albeit at a relatively low frequency. This study demonstrates the use of whole‐genome sequences as a promising avenue for delimiting species boundaries and further advocates for an integrative approach in the assessment of species delimitation. [ABSTRACT FROM AUTHOR]

A new AgOTf‐catalyzed domino reaction of 2‐alkynylbenzaldehyde and 4‐amino‐1‐methyl‐3‐propyl‐1H‐pyrazole‐5‐carboxamide has been reported via a sequential condensation, cyclization, and acetylenic hydroamination process. The developed protocol provides an efficient and modular access to a range of new fused tetracyclic heterocycle 6‐aryl‐9‐methyl‐11‐propyl pyrazolo[4′,3′:4,5]pyrimido[2,1‐a]isoquinolin‐8(9H)‐ones with two new rings in good yields. [ABSTRACT FROM AUTHOR]

It has recently been hypothesized that genetic markers experiencing high rates of gene flow would be better suited to differentiate closely related species. We tested this hypothesis by examining genetic variation in the chloroplast (cp) DNA (trnS-trnG and trnL-trnF) and mitochondrial (mt) DNA (nad5 intron 4 and nad7 intron 1) of two fir species, Abies nephrolepis (Trautv.) Maxim. and Abies holophylla Maxim., with overlapping distributions in northeastern China. Two mitotypes were identified; one was common to both species, whereas the other occurred only in A. holophylla. How-ever, four chlorotypes were identified, clustered into two species-specific groups exhibiting distinct mutations; species delimitation using these generated genetic variants was congruent with those obtained by morphological delimitation. Our findings supported the hypotheses that cpDNA, with its high rates of gene flow, is more useful than mtDNA for species de-limitation in fir trees. In addition, the low intraspecific diversity observed for both species may result from their repeated range retractions and expansions in response to climatic oscillations in the history. Resume: Certains ont recemment emis l'hypothese que les marqueurs genetiques caracterises par un taux eleve de flux genique seraient plus aptes a differencier des especes etroitement apparentees. Les auteurs ont teste cette hypothese en etudiant la variation genetique de l'ADN chloroplastique (cp) (trnS-trnG et trnL-trnF) et de l'ADN mitochondrial (mt) (nad5 intron 4 et nad7 intron 1) de deux especes de sapin, Abies nephrolepis (Trautv.) Maxim. et Abies holophylla Maxim., dont les aires de repartition se chevauchent dans le nord-est de la Chine. Deux mitotypes dont un etait commun aux deux especes et l'autre apparaissait uniquement chez A. holophylla ont ete identifies. Toutefois, quatre chlorotypes qui se regroupaient en deux groupes specifiques aux especes et demontraient des mutations distinctives ont ete identifies. La delimitation des especes ba-see sur ces polymorphismes genetiques correspondait a celle obtenue a l'aide des caracteres morphologiques. Nos resultats supportent l'hypothese que l'ADNcp, avec son taux eleve de flux genique, est plus utile que l'ADNmt pour delimiter les especes chez le sapin. Egalement, la faible diversite intraspecifique notee chez les deux especes pourrait resulter de cycles repetes de contraction et d'expansion des aires naturelles de repartition en reponse aux oscillations climatiques passees. [Traduit par la Redaction], Introduction Genetic delineating of the diverse species is a key issue in biology, particularly in the conservation and utilization of natural resources (Comes and Abbott 2001; Van Dyke 2008). However, [...]

A CuI/L‐proline‐catalyzed reaction of 2‐(2‐bromophenyl)‐4,5‐diaryl‐1H‐imidazole and potassium ethylxanthate unexpectedly gave bis(2‐(4,5‐diaryl‐1H‐imidazol‐2‐yl)phenyl)sulfane derivatives in high yields, rather than 2,3‐diphenyl‐5H‐benzo[e]imidazo[1,2‐c]thiazine‐5‐thione. This cascade procedure provided an efficient method to synthesize diphenylsulfanes using potassium ethylxanthate as a new type of sulfur source via the Csp2S bond Ullmann reaction twice. [ABSTRACT FROM AUTHOR]