Tertiary montane origin of the Central Asian flora, evidence inferred from cpDNA sequences of Atraphaxis (Polygonaceae)

Phytochemical Screening Using LC-MS to Study Antioxidant and Toxicity Potential of Methanolic Extracts of Atraphaxis pyrifolia Bunge

Atraphaxis pyrifolia, a native medicinal plant of Central Asia, has a long history of traditional medicinal use; however, scientific research on its phytochemical and biological properties remains scarce. This paper aims to elucidate its chemical profile and assess its pharmacological potential through a comprehensive investigation of the phytochemical composition of stems and leaves using Liquid Chromatography-Mass Spectrometry (LC-MS), in conjunction with the assessment of its antioxidant (DPPH and ABTS) and cytotoxicity test on Artemia salina. Predominantly, glycosylated flavonoids were detected in stems and leaves extracts, notably including 8-Acetoxy-3',4',5,5'-tetrahydroxy-7-methoxy-3-α-L-rhamno-pyranosyloxyflavone, pyrifolin, and dehydroxypyrifolin. While the latter compound is exclusive to A. pyrifolia, the former compounds serve as shared chemical markers with other Atraphaxis species. The methanolic extracts of A. pyrifolia leaves exhibited significant antioxidant capacity without toxicity against Artemia salina. This study contributes to current research through providing valuable insights into the chemical diversity and potential medicinal properties of this plant species.

Plastid phylogenomics sheds light on divergence time and ecological adaptations of the tribe Persicarieae (Polygonaceae)

Southwestern China, adjacent to the Qinghai-Tibetan Plateau (QTP), is known as a hotspot for plant diversity and endemism, and it is the origin and diversification center of Persicarieae. As one of the major lineages in Polygonaceae, Persicarieae represents a diverse adaptation to various habitats. As a result of morphological plasticity and poorly resolving molecular markers, phylogenetic relationships and infrageneric classification within Persicarieae have long been controversial. In addition, neither plastome phylogenomic studies nor divergence time estimates on a larger sample of Persicarieae species have been made thus far. We sequenced and assembled 74 complete plastomes, including all of the recognized genera within Persicarieae and their relatives. We conducted a comprehensive phylogenetic study of the major clades within Persicarieae and, based on the thus obtained robust phylogeny, also estimated divergence time and the evolution of diagnostic morphological traits. Major relationships found in previous phylogenetic studies were confirmed, including those of the backbone of the tree, which had been a major problem in previous phylogenies of the tribe. Phylogenetic analysis revealed strong support for Koenigia as sister to Bistorta, and together they were sister to the robustly supported Persicaria. Based on the phylogenetic and morphological evidence, we recognize five sections in Persicaria: Persicaria, Amphibia, Tovara, Echinocaulon, and Cephalophilon. It is estimated that the divergence of the Persicarieae began around the late Paleocene, with diversification concentrated in the Eocene and Miocene. In addition, it is suggested that the increasing westerly and monsoon winds in conjunction with the uplift of the QTP may be the driving force for origin and diversification of Persicarieae species. These results provide a valuable evolutionary framework for the study of adaptation in Polygonaceae and insights into plant diversification on the QTP and adjacent areas.

Phylogeny and Historical Biogeography of Veronica Subgenus Pentasepalae (Plantaginaceae): Evidence for Its Origin and Subsequent Dispersal

Simple Summary

The Irano-Turanian phytogeographical region is considered a biodiversity reservoir for adjacent regions. The present phylogeographic study suggests that Veronica subgenus Pentasepalae originated in the Iranian plateau and was dispersed via a North African route to the Mediterranean and the Euro-Siberian regions. These findings highlight the importance of the Iranian plateau as a center of origin for many temperate plant species. Our results also resolve several taxonomic and phylogenetic issues surrounding the Southwest Asian species of this subgenus.

Abstract

Veronica subgenus Pentasepalae is the largest subgenus of Veronica in the Northern Hemisphere with approximately 80 species mainly from Southwest Asia. In order to reconstruct the phylogenetic relationships among the members of V. subgenus Pentasepalae and to test the “out of the Iranian plateau” hypothesis, we applied thorough taxonomic sampling, employing nuclear DNA (ITS) sequence data complimented with morphological studies and chromosome number counts. Several high or moderately supported clades are reconstructed, but the backbone of the phylogenetic tree is generally unresolved, and many Southwest Asian species are scattered along a large polytomy. It is proposed that rapid diversification of the Irano-Turanian species in allopatric glacial refugia and a relatively high rate of extinction during interglacial periods resulted in such phylogenetic topology. The highly variable Asian V. orientalis–V. multifida complex formed a highly polyphyletic assemblage, emphasizing the idea of cryptic speciation within this group. The phylogenetic results allow the re-assignment of two species into this subgenus. In addition, V. bombycina subsp. bolkardaghensis, V. macrostachya subsp. schizostegia and V. fuhsii var. linearis are raised to species rank and the new name V. parsana is proposed for the latter. Molecular dating and ancestral area reconstructions indicate a divergence age of about 9 million years ago and a place of origin on the Iranian Plateau. Migration to the Western Mediterranean region has likely taken place through a North African route during early quaternary glacial times. This study supports the assumption of the Irano-Turanian region as a source of taxa for neighboring regions, particularly in the alpine flora.

Natural Bioactive Cinnamoyltyramine Alkylamides and Co-Metabolites

Natural products are a vital source for agriculture, medicine, cosmetic and other fields. Among them alkylamides are a broad and expanding group found in at least 33 plant families. Frequently, they possess a simple carbon skeleton architecture but show broad structural variability and important properties such as immunomodulatory, antimicrobial, antiviral, larvicidal, insecticidal and antioxidant properties, amongst others. Despite to these several and promising biological activities, up to today, only two reviews have been published on natural alkylamides. One focuses on their potential pharmacology application and their distribution in the plant kingdom and the other one on the bioactive alkylamides specifically found in Annona spp. The present review is focused on the plant bioactive cinnamoyltyramine alkylamides, which are subject of several works reported in the literature. Furthermore, the co-metabolites isolated from the same natural sources and their biological activities are also reported.

Evolutionary history of the Pasque-flowers (Pulsatilla, Ranunculaceae): Molecular phylogenetics, systematics and rDNA evolution

Pulsatilla (Anemoneae, Ranunculaceae) is sister to Anemone s.s. and contains ca 40 perennial species of considerable horticultural and medical importance. We sequenced 31 of those species, plus nine subspecies, two cultivars and six outgroups, for two nuclear regions (high-copy nrITS and low-copy MLH1) and three plastid regions (rbcL, accD-psaI, trnL intron) in order to generate the first comprehensive species-level phylogeny of the genus. Phylogenetic trees were constructed using both concatenation-based (maximum likelihood and Bayesian inference) and coalescence methods. The better supported among the internal nodes were subjected to molecular clock dating and ancestral area reconstruction, and karyotypic characters identified by us using Fluorescence In Situ Hybridization were mapped across the tree. The preferred species tree from the coalescence analysis formed the basis of a new infrageneric classification based on monophyly plus degree of divergence. The earliest divergent of the three subgenera, Kostyczewianae, is represented by only a single species that is morphologically intermediate between Anemone s.s. and 'core' Pulsatilla. Subgenus Pulsatilla is considerably richer in species than its sister subgenus Preonanthus and contains three monophyletic sections. Species possessing nodding flowers and pectinately dissected leaves are phylogenetically derived compared with groups possessing erect flowers and palmately lobed leaves. Pulsatilla separated from Anemone s.s. at ca 25 Ma. Our results indicate a central Asian mountain origin of the genus and an initial diversification correlated with late Tertiary global cooling plus regional mountain uplift, aridification and consequent expansion of grasslands. The more rapid and extensive diversification within subgenus Pulsatilla began at ca 3 Ma and continued throughout the Quaternary, driven not only by major perturbations in global climate but also by well-documented polyploidy.

Insight into Central Asian flora from the Cenozoic Tianshan montane origin and radiation of Lagochilus (Lamiaceae)

The Tianshan Mountains play a significant role in the Central Asian flora and vegetation. Lagochilus has a distribution concentration in Tianshan Mountains and Central Asia. To investigate generic spatiotemporal evolution, we sampled most Lagochilus species and sequenced six cpDNA locations (rps16, psbA-trnH, matK, trnL-trnF, psbB-psbH, psbK-psbI). We employed BEAST Bayesian inference for dating, and S-DIVA, DEC, and BBM for ancestral area/biome reconstruction. Our results clearly show that the Tianshan Mountains, especially the western Ili-Kirghizia Tianshan, as well as Sunggar and Kaschgar, was the ancestral area. Ancestral biome was mainly in the montane steppe zone of valley and slope at altitudes of 1700–2700 m, and the montane desert zone of foothill and front-hill at 1000–1700 m. Here two sections Inermes and Lagochilus of the genus displayed “uphill” and “downhill” speciation process during middle and later Miocene. The origin and diversification of the genus were explained as coupled with the rapid uplift of the Tianshan Mountains starting in late Oligocene and early Miocene ca. 23.66~19.33 Ma, as well as with uplift of the Qinghai-Tibetan Plateau (QTP) and Central Asian aridification.

Antioxidant Flavonols and Phenolic Compounds from Atraphaxis frutescens and Their Inhibitory Activities against Insect Phenoloxidase and Mushroom Tyrosinase

Chemical investigation of the aerial parts of Atraphaxis frutescens resulted in the isolation of five 7-methoxyflavonols with pyrogallol B-ring moieties (1-5), a fisetinidol glucoside (13), and a benzyl glycoside (18), together with 26 known compounds including flavonoids, phenylpropanoid amides, anthraquinone glycosides, lignans, and a benzyl derivative. The principal chemical structural feature of the isolated compounds was either a pyrogallol or catechol B-ring moiety, and they showed potent 1,1-diphenyl-2-picrylhydrazyl radical scavenging activities. To assess the effects of these antioxidants on biological enzymes, their inhibitory effects against an insect phenoloxidase and a mushroom tyrosinase were evaluated. This study indicated that insect phenoloxidase was inhibited by phenylpropanoid amides and that mushroom tyrosinase was inhibited by the characteristic 7-methoxyflavonol 3-O-rhamnopyranosides.

Phylogeographic History of Atraphaxis Plants in Arid Northern China and the Origin of A. bracteata in the Loess Plateau

In China, species of Atraphaxis (Polygonaceae) primarily inhabit arid zones across temperate steppe and desert regions. The complex geologic history (e.g., expansion of deserts) and extreme climate shifts of the region appear to have played an important role in shaping the phylogeography of Atraphaxis. The present study focuses on species-level phylogeographic patterns of Atraphaxis in China, with the goal of determining the impact of past environmental changes, in northern China, on the evolutionary history of the genus. Five hundred and sixty-four individuals distributed among 71 populations of 11 species of Atraphaxis from across the geographic range of the genus were studied using sequence data from two plastid spacers, psbK-psbI and psbB-psbH. The results demonstrate that most chloroplast haplotypes are species-specific, except for some present among widespread species. The phylogeny of Atraphaxis was well structured, and molecular dating analyses suggest that the main divergence events occurred during the late Pliocene and Pleistocene (5.73–0.03 million years ago). The statistical dispersal-vicariance analysis (S-DIVA) results provide evidence that phylogeographic patterns for the genus were characterized by both vicariance events and regional dispersal. The presented data suggest that the rapid expansion of deserts and climatic changes in northern China during the late Pliocene and Pleistocene have driven the diversification and spread of Atraphaxis in the region. The expansion of the Tengger Desert provided appropriate conditions for the origin of A. bracteata. Additionally, a contact zone in the north of the Hexi Corridor was identified as having played a significant role as a migratory route for species in adjacent areas.

What is Atraphaxis L. (Polygonaceae, Polygoneae): cryptic taxa and resolved taxonomic complexity instead of the formal lumping and the lack of morphological synapomorphies

BACKGROUND

The recently proposed recircumscription of the genus Atraphaxis (incl. Atraphaxis section Ovczinnikovia O.V. Yurtseva ex. S. Tavakkoli and Polygonum sect. Spinescentia Boissier (=A. sect. Polygonoides S. Tavakkoli, Kaz. Osaloo & Mozaff.) makes this genus fairly heterogeneous and therefore almost undefinable based on morphology. A critical comprehensive reappraisal of the group is necessary.

METHODS

Using the DNA sequence data (ITS1&2 regions of nrDNA and combined trnL intron + trnL-F IGS and rpl32-trnL((UAG)) IGS regions of plastid genome), Maximum Likelihood (ML) and Bayesian analyses (BI) were applied for phylogenetic reconstructions of the tribe Polygoneae with special attention to Atraphaxis, and related taxa. Maximum parsimony reconstructions of the evolution of perianth morphology and sporoderm ornamentation in the tribe Polygoneae were also performed. Life history, morphology of shoots, leaf blades, ocreas, perianth and achene morphology, ultrasculpture of achene surface, and pollen morphology were compared, and SEM and LM images were provided.

PRINCIPAL FINDINGS

The genera Atraphaxis and Polygonum were found to be widely polyphyletic. The rarest and morphologically remarkable endemic of Tian-Shan and Pamir Atraphaxis ovczinnikovii (Atraphaxis sect. Ovczinnikovia O.V. Yurtseva ex. S. Tavakkoli) was confirmed to be a sister of the clade (Atraphaxis + Polygonum sect. Spinescentia) in plastid topology. The genus Bactria (=Atraphaxis sect. Ovczinnikovia), which circumscribes two species, is newly established as a result of this analyses. Morphological data confirm the originality of the taxon.

DISCUSSION

We are arguing for a narrow delimitation of Atraphaxis with petalloid segments and striato-perforate sporoderm ornamentation as morphological synapomorphies. The recently proposed inclusion of Polygonum sect. Spinescentia in Atraphaxis is fairly questionable from a morphological standpoint. The rank of Polygonum sect. Spinescentia requires further clarification. The generic composition of the tribe Polygoneae also requires future reappraisals.

Evolution of Asian Interior Arid-Zone Biota: Evidence from the Diversification of Asian Zygophyllum (Zygophyllaceae)

The Asian interior arid zone is the largest desert landform system in the Northern Hemisphere, and has high biodiversity. Little is currently known about the evolutionary history of its biota. In this study, we used Zygophyllum, an important and characteristic component of the Asian interior arid zone, to provide new insights into the evolution of this biota. By greatly enlarged taxon sampling, we present the phylogenetic analysis of Asian Zygophyllum based on two plastid and one nuclear markers. Our phylogenetic analyses indicate that Asian Zygophyllum and Sarcozygium form a clade and Sarcozygium is further embedded within the shrub subclade. An integration of phylogenetic, biogeographic, and molecular dating methods indicates that Zygophyllum successfully colonized the Asian interior from Africa in the early Oligocene, and Asian Zygophyllum became differentiated in the early Miocene and underwent a burst of diversification in the late Miocene associated with the expansion of Asian interior arid lands due to orogenetic and climatic changes. Combining diversification patterns of other important components of the Asian interior arid zone, we propose a multi-stage evolution model for this biota: the late Eocene-early Oligocene origin, the early Miocene expansion, and the middle-late Miocene rapid expansion to the whole Asian interior arid zone. This study also demonstrates that, for Zygophyllum and perhaps other arid-adapted organisms, arid biomes are evolutionary cradles of diversity.

Young dispersal of xerophil Nitraria lineages in intercontinental disjunctions of the Old World

Many cases of intercontinental disjunct distributions of seed plants have been investigated, however few have concerned the continents of Eurasia (mainly Central Asia), Africa, and Australia, especially the xerophytic lineages are lacking. Nitraria (Nitrariaceae) is just one of these xerophytic lineages. Previous Nitraria studies have hypothesized either Africa as the ancient center, with dispersals to Australia and Eurasia, or alternatively Central Asia, due to a concentration of endemism and diversity there. Our findings show eastern Central Asia, i.e. the eastern Tethys, to be the correct place of origin. Dispersal westward to Africa occurred during the late Oligocene to Pliocene, whereas dispersal to Australia from western Central Asia was young since Pliocene 2.61 Ma. Two related tetraploids are indicated to have diversified in eastern Central Asia at approximately 5.89 Ma, while the Australian tetraploid N. billardieri, is an independently derived, recent dispersal from western Central Asia.