Center Of Origin Research Articles

Phytochemical Screening and Bioactivities of Cactaceae Family Members Endemic to Mexico.

Mexico is a center of diversification for the Cactaceae family, with 69% of the species recorded as endemic. Certain members of the Cactaceae family have been chemically analyzed to relate their medicinal use with their phytochemistry. Here, the phytochemistry and bioactivity of ethanol extracts of Ferocactus echidne, F. latispinus, and Mammillaria geminispina were evaluated. A preliminary phytochemical analysis was performed, detecting the presence of saponins, tannins, cardiotonic glycosides, and sesquiterpene lactones. The presence of nicotinic acid in F. echidne and F. latispinus was identified by GC-MS. Other compounds found in the extracts of these three species were gentisic acid, diosmetin, chlorogenic acid, N-methyltyramide, and hordenine. The antioxidant activity was estimated with the DPPH free radical scavenging test. To determine the toxicity of the extracts, the in vivo model of Artemia spp. was used. In addition, the cytotoxicity of the extract was tested on C6, HaCaT, THP-1, and U937 cell lines, while the inflammatory activity was tested by measuring the secretion of cytokines using macrophage cells. The three species showed different bioactivities, including antioxidant, antimicrobial, cytotoxic, and anti-inflammatory activities. To the best of our knowledge, the results presented here are the first described for these species.

Development of Genomic Resources in Mexican Bursera (Section: Bullockia: Burseraceae): Genome Assembly, Annotation, and Marker Discovery for Three Copal Species.

Bursera comprises ~100 tropical shrub and tree species, with the center of the species diversification in Mexico. The genomic resources developed for the genus are scarce, and this has limited the study of the gene flow, local adaptation, and hybridization dynamics. In this study, based on ~155 million Illumina paired-end reads per species, we performed a de novo genome assembly and annotation of three Bursera species of the Bullockia section: Bursera bipinnata, Bursera cuneata, and Bursera palmeri. The total lengths of the genome assemblies were 253, 237, and 229 Mb for B. cuneata, B. palmeri, and B. bipinnata, respectively. The assembly of B. palmeri retrieved the most complete and single-copy BUSCOs (87.3%) relative to B. cuneata (86.5%) and B. bipinnata (76.6%). The ab initio gene prediction recognized between 21,000 and 32,000 protein-coding genes. Other genomic features, such as simple sequence repeats (SSRs), were also detected. Using the de novo genome assemblies as a reference, we identified single-nucleotide polymorphisms (SNPs) for a set of 43 Bursera individuals. Moreover, we mapped the filtered reads of each Bursera species against the chloroplast genomes of five Burseraceae species, obtaining consensus sequences ranging from 156 to 160 kb in length. Our work contributes to the generation of genomic resources for an important but understudied genus of tropical-dry-forest species.

Floral synomone components of fruit fly-attracting orchids, Bulbophyllum sinapis and B. hahlianum, in Papua New Guinea

Papua New Guinea (PNG) is known as the center of diversification of the largest orchid genus Bulbophyllum . In order to understand the ecological adaptation mechanisms in two closely related Dacini fruit fly-attracting orchids species, B. sinapis and B. hahlianum, their floral synomone components were examined. Flowers of B. sinapis attract males of various agricultural pest fruit fly species, such as Bactrocera musae and Ba. umbrosa, with methyl eugenol (a phenylpropanoid). However, flowers of B. hahlianum, attract fruit fly males belonging to a more diverse group of cue-lure-responsive species, namely, Ba. frauenfeldi, Ba. bryoniae and Zeugodacus cucurbitae with a mixture of phenylbutanoids including anisyl acetone (AA), raspberry ketone (RK) and zingerone (ZN). Contents of the volatiles in floral parts of both species were quantified. The highest contents of floral volatiles were detected in the lateral sepals of both the Bulbophyllum species. Attractant activity of synthetic AA, RK and ZN was examined in a local habitat in East New Britain. Furthermore, male flies attracted to B. hahlianum were found to sequester RK in the body tissues in varying quantities, which suggests its role as a sex pheromonal component to attract conspecific females as in the case of other Dacini fruit fly species through pharmacophagous acquisition of the orchid synomone. • Papua New Guinean orchids attract males of Dacini fruit flies with floral volatiles (83). • Floral synomone possesses either phenylpropanoid or phenylbutanoid male attractants (83). • Consume floral volatiles used by male flies as sex pheromone to attract females (80). • Biochemical and phylogenetic relationships of daciniphilous orchids are examined (80).

Spatial distribution of species richness and endemism of Solanum (Solanaceae) in Mexico

The spatial distribution of the species richness is not aleatory. It responds to evolutionary, geographical, and climatic events, and it is important to establish biodiversity management and conservation priorities. The mountainous zones around the globe have been identified as centers of plant diversification. In Mexico, the Mexican Transition Zone (MTZ) which comprises the main mountainous chains is recognized as an area of high species richness and endemism. The genus Solanum (Solanaceae) includes 1228 accepted species distributed all over the world, but with centers of species richness and endemism in the neotropical mountains. Based on patterns observed in geographical distribution of Mexican biodiversity, we expect the MTZ to host the highest species richness and endemism of Solanum. Here, we evaluated the spatial distribution of the species richness and endemism of Solanum in Mexico. For that purpose, we used 10043 unique georeferenced records obtained from herbarium specimens, specimens cited in literature and electronic databases. Then, we quantified species richness and endemism using biogeographical regions and provinces, a grid-cell of 50 × 50 km, political division, vegetation types, elevational, latitudinal, as well as longitudinal gradients. In addition, we analyzed endemism through weighted endemism and corrected weighted endemism. In Mexico, there were 134 species of Solanum including 43 endemics. The species richness and endemism were concentrated along the MTZ, specifically in the Chiapas Highlands, Sierra Madre del Sur (SMS), and Transmexican Volcanic Belt (TVB). Eight cells containing 63.43% of the species were obtained in the grid-cell analysis. The species richness distribution assessment by vegetation type, elevation, and political division confirmed the MTZ as the richest region. Likewise, the endemism was found along the MTZ in the Sierra Madre Oriental, SMS, TVB as well as in Chihuahuan Desert. Complex geological and paleoclimatic history, irregular topography, current climate diversity, dispersal, and persistence influenced these patterns. Lastly, we confirmed the remarkable importance of the MTZ as a center of origin, diversification and endemism of Mexican plants, using one of the most representative genera in Mexico.

Phenotypic and Genotypic Diversity of the Tomato Germplasm From the Lazio Region in Central Italy, With a Focus on Landrace Distinctiveness.

Italy is a recognized secondary center of diversification for cultivated tomato (Solanum lycopersicum L.). The study of phenotypic and genetic diversity in landrace collections is important for germplasm conservation and valorization. Here, we set up to study the tomato germplasm collected in the region of Lazio in Central Italy, with a focus on the distinctiveness among landraces and the attribution of membership to unnamed accessions. Our regional collection included 32 accessions belonging to eight different locally recognized landraces and 19 unnamed accessions. All accessions were gathered from local farmers and are preserved in the collection held at the Regional Agency for the Development and the Innovation of Lazio Agriculture (ARSIAL) and at the University of Tuscia. We included 13 control genotypes comprising nine landraces from neighbor regions and four reference cultivars. The collection showed wide phenotypic variability for several qualitative and quantitative traits, such as leaf border and shape, inflorescence type, fruit shape, green shoulder, fruit weight (range 14–277 g), locule number (2–12), shape index (0.54–2.65), yield (0.24–3.08 kg/plant), and soluble solids (3.4–7.5°B). A few landraces showed uncommon phenotypes, such as potato leaf, colorless fruit epidermis, or delayed ripening. Multivariate analysis of 25 cardinal phenotypic variables separated the accessions into two distinct groups; accessions showing a flattened-ribbed fruit were distinguished from those with round to elongate fruits with smooth structure. Genotyping analysis of 7,720 SNPs was performed using the tomato array platform SolCAP, to point out the genetic relationship among the studied accessions. A neighbor-joining tree analysis allowed to confirm or deny phenotypic data and to assign some of the unnamed accessions to recognized groups. Allelic status at marker loci linked to resistance genes commonly used in breeding identified accessions putatively derived from modern material or commercial hybrids, thus not classifiable as landraces. Overall, this study provided the information useful to preserve, valorize, and juridically protect tomato local landraces from the Lazio region and will in addition be helpful to their improvement by breeding.

DNA barcoding, phylogeny and phylogeography of the cyst nematode species of the Humuli group from the genus Heterodera (Tylenchida: Heteroderidae)

Summary The Humuli group of the genus Heterodera contains species that parasitise dicotyledons and are characterised by a lemon-shaped cyst having a bifenestrate vulval cone (ambifenestrate for H. fici), long vulval slit and weak underbridge. Presently, the Humuli group includes seven species: H. amaranthusiae, H. fici, H. humuli, H. litoralis, H. ripae, H. turcomanica and H. vallicola. In this study we provided comprehensive phylogenetic analyses of COI and ITS rRNA gene sequences of species from the Humuli group using Bayesian inference, maximum likelihood, and maximum and statistical parsimony. All seven valid species from the Humuli group, one putatively new species belonging to this group and the willow cyst nematode, H. salixophila, sharing a common ancestor with the Humuli group, were analysed. Some 84 COI and 5 ITS rRNA new gene sequences from 37 nematode populations collected from 12 countries were obtained in this study. Our results confirmed that the COI gene is a powerful DNA barcoding marker for identification of populations and species from the Humuli group. Based on the results of phylogeographical analysis and age estimation of clades with a molecular clock approach, it was hypothesised that some species of the Humuli group primarily originated and diversified in Western and Middle Asian regions during the Pleistocene and Holocene periods and then dispersed from this region across the world. Two secondary diversification centres of the Humuli group were likely located in East and Southeast Asia, Russian Far East, and Oceania.

Review on Heterosis and Combining Ability Study for Yield and Morphological Characters of Coffee (Coffea arabica L) in Ethiopia

Ethiopia is both the center of origin and diversification of Coffee arabica. Despite the existence of high genetic diversity in coffee population that provides immense opportunities for improvement program, shortage of improved varieties (pure line and hybrid varieties) is the major one. It is obvious that research work carried out so far on coffee genetics and breeding was not adequate to address these diverse agro-ecologies of the country. Heterosis and combining ability studies are some of the basic breeding tools to address such problems. Some studies had been focused on assessment of heterosis and combining ability analysis for yield and morphological characters of coffee in Ethiopia and the presence of heterosis was reported in crosses of selected indigenous C. arabica L. varieties in Ethiopia under different set of studies mainly due to presence of diverse parental lines. These results clearly suggested that the possibility to bring significant coffee improvement through heterosis and combining ability analysis. Therefore, continuous crossing program should be required to acquire many more cross combinations for intensive and extensive evaluation to develop better performing and high yielding hybrids for Ethiopian origin coffee. Keywords: Coffee Arabica, morphological traits, yield, Heterosis and combining ability DOI: 10.7176/JEES/12-7-02 Publication date: July 31 st 2022

Cross-Species Transmission of Bat Coronaviruses in the Americas: Contrasting Patterns between Alphacoronavirus and Betacoronavirus.

ABSTRACTBats harbor the largest number of coronavirus (CoV) species among mammals, serving as major reservoirs of alphaCoVs and betaCoVs, which can jump between bat species or to different mammalian hosts, including humans. Bat-CoV diversity is correlated with host taxonomic diversity, with the highest number of CoV species found in areas with the highest levels of bat species richness. Although the Americas harbor a unique and distinctive CoV diversity, no cross-species transmission (CST) or phylogeographic analysis has yet been performed. This study analyzes a large sequence data set from across the Americas through a Bayesian framework to understand how codivergence and cross-species transmission have shaped long-term bat-CoV evolution and ultimately identify bat hosts and regions where the risk of CST is the highest. Substantial levels of CST were found only among alphaCoVs. In contrast, cospeciation prevailed along the evolution of betaCoVs. Brazil is the center of diversification for both alpha and betaCoVs, with the highest levels of bat species richness. The bat family Phyllostomidae has played a key role in the evolution of American bat-CoVs, supported by the highest values of host transition rates. Although the conclusions drawn from this study are supported by biological/ecological evidence, it is likely that novel lineages will be discovered, which could also reveal undetected CSTs given that sequences are available from 11 of the 35 countries encompassing the Americas. The findings of this study can be useful for conducting targeted discovery of bat-CoVs in the region, especially in countries of the Americas with no reported sequences.IMPORTANCE Coronaviruses (CoVs) have a strong zoonotic potential due to their high rates of evolvability and their capacity for overcoming host-specific barriers. Bats harbor the largest number of CoV species among mammals, with the highest CoV diversity found in areas with the highest levels of bat species richness. Understanding their origin and patterns of cross-species transmission is crucial for pandemic preparedness. This study aims to understand how bat-CoVs diversify in the Americas, circulate among and transmit between bat families and genera, and ultimately identify bat hosts and regions where the risk of CoV spillover is the highest.

Comparing Wild and Cultivated Food Plant Richness Between the Arid American and the Mesoamerican Centers of Diversity, as Means to Advance Indigenous Food Sovereignty in the Face of Climate Change

Climate change is aggravating agricultural crop failures, and the paucity of wild food harvests for Indigenous desert dwellers in Mexico and the U.S. This food production crisis challenges ongoing efforts by Indigenous communities in obtaining greater food security, prompting them to reconsider the value of traditional Indigenous food systems in both Mesoamerica and Arid America, two adjacent centers of crop diversity. While food production strategies in these two centers share many features, the food plant diversity in the Western Mesoamerican region appears to be greater. However, a higher percentage of plants in Arid America have adapted to water scarcity, heat, and damaging radiation. The phytochemical and physiological adaptations of the food plants to abiotic stresses in arid environments offer a modicum of resilience in the face of aggravated climate uncertainties. By comparing food plant genera comprising Western Mesoamerican and Arid American diets, we detected a higher ratio of CAM succulents in the wild and domesticated food plant species in the Arid American food system. We conclude that food plant diversity in the ancestral diets of both centers can provide much of the resilience needed to advance Indigenous food sovereignty and assure food security as climate change advances.

A new cynodont from the Upper Triassic Los Colorados Formation (Argentina, South America) reveals a novel paleobiogeographic context for mammalian ancestors

Probainognathia is a derived lineage of cynodonts which encompass Mammalia as their crown-group. The rich record of probainognathians from the Carnian of Argentina contrasts with their Norian representation, with only one named species. Here we describe a new probainognathian, Tessellatia bonapartei gen. et sp. nov., from the Norian Los Colorados Formation of the Ischigualasto-Villa Unión Basin of Argentina. The new taxon, represented by a partial cranium with associated lower jaws, was analyzed through neutron and X-rays micro-tomography (μCT). The high-resolution neutron μCT data allowed the identification of a unique character combination, including features inaccessible through traditional techniques. We constructed the largest phylogenetic data matrix of non-mammalian cynodonts. The new species and its sister taxon, the Brazilian Therioherpeton cargnini, are recovered as probainognathians, closely related to Mammaliamorpha. We conducted the first quantitative paleobiogeographic analysis of non-mammalian cynodonts, focusing in probainognathians. The results indicate that Probainognathia and Mammaliamorpha originated in southwestern Gondwana (in the Brazilian Paraná Basin), which was an important center of diversification during the Triassic. Finally, the Chinese Lufeng Basin is identified as the ancestral area of Mammaliaformes. These new findings, besides adding to the knowledge of the poorly represented Norian cynodonts from the Los Colorados Formation, are significant to improve our understanding of probainognathian diversity, evolution, and paleobiogeographic history.

Is the genetic integrity of wild Coffea canephora from Ivory Coast threatened by hybridization with introduced coffee trees from Central Africa?

Robusta coffee (Coffea Canephora) is an important source of income and employment, contributing significantly to the economies of many developing countries. This species is split into two genetic groups: Guinean and Congolese. Côte-d’Ivoire is the primary diversification center of the Guinean pool, which offers great potential for genetic improvement. However, genetic erosion of this group is currently a threat in this country because of the massive introduction of Congolese accessions done in the previous decades. In this work, we analyzed the progenies of isolated population of C. canephora composed of a mix of Guinean and Congolese using SNP markers. The analysis is focus on the male parents’ contribution in open pollination. The results show that the introduction of cultivars from the Congolese gene pool threat the genetic integrity of wild populations from the Guinean gene pool. Indeed, this analysis showed that Congolese pollens have more ability to pollinate the Guinean group than the Guinean pollen perform on Congolese trees. We recommend that a program be put in place to ensure the conservation of wild population of C. canephora through in situ or ex situ conservation.

Characterization of Bolivian chili peppers; antioxidant capacity, total phenolic compounds, capsaicin and β-carotene concentration

Purpose Chili pepper pods are a worldwide used and cultivated spice with a high economic and cultural importance. Bolivia is a center of origin and diversification of important crops including wild pepper varieties, but little is known about the chemical composition, antioxidant activity and the Scoville and bioactive compounds of these chili peppers. The purpose of this study was to contribute with new data about the chemical composition and the Scoville scale of Bolivian Chili peppers. Design/methodology/approach A total of 26 samples of Bolivian Chili peppers were extracted using distilled water and methanol. Total antioxidant capacity was determined by the ferric-reducing antioxidant power (FRAP) and by the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) methods. The total phenolic content was determined by Folin and Ciocalteu. Carotene, protein and ashes were determined by Bolivian analytical norms. Capsaicin was determined by high-performance liquid chromatography. All determinations were expressed as mean values± standard deviation of six replicates measured over three days of one extract. All values were less than 5% of coefficient of variation. Principal component analysis was applied to reveal patterns in the data. PC1 and PC2 together explained 78% of the total variance. Findings The protein content (3.8–6.3 g/100 g of dw) and the antioxidant activity (88.2 to 374 by FRAP and 87.0 to 172 evaluated by ABTS) studied in these species revealed that the values were above the average reported in the literature. The amount of pungency or capsaicin content expressed as Scoville Heat Units were reported moderately highly and very highly pungent (5,696–148,800 g dw) in several of the Bolivian peppers which demonstrates a good potential for capsaicin extraction and different applications for industry and as food ingredients. Originality/value This manuscript presents an important and novel contribution to the knowledge of the chili peppers in the region.

Historical biogeography of a rapid and geographically wide diversification in Neotropical mammals

AbstractAimTropical South America, in particular Amazonia, has been identified as the area of the basal diversification of several large mammal clades. Whether this scenario also holds for younger and widely distributed clades remains unclear. Here, we assessed the historical biogeography of a young but diverse and widely distributed mammal clade.LocationThe Neotropics.TaxonLong‐tailed mice of the genus Oligoryzomys.MethodsWe estimated a dated species tree by sampling five genes (one mitochondrial and four nuclear) from 30 of the 32 living species of the genus. We inferred the distribution of the most recent common ancestors (MRCAs) of distinct species groups, using a 13 ecoregion scheme and fitting three biogeographical models, to simulate dispersal events under the selected model.ResultsThe DEC model best explained the diversification of Oligoryzomys. The MRCA of the genus had an age of ~2.64 Mya and its ancestral area was inferred as a large region encompassing Boreal and Southern Amazonia, Chaco and Tropical Andes. Subsequent vicariance events, followed by dispersal events towards the present, account for its diversification and wide distribution.Main conclusionThe biogeographical history of Oligoryzomys is complex. It originated in the northern half of South America; and then after a series of vicariant events, a series of dispersion events allowed it to colonize southern South America, the Andes and closer to the present Central and North America. This radiation, which constitutes one of the fastest and largest Pleistocene diversifications of Neotropical mammals, involves events previously suggested for other groups (e.g. Andean diversification), others that are novel for rodents and for the most part for South American mammals (e.g. the identification of the Chaco as a centre of diversification).

Identification of conserved and new miRNAs that affect nodulation and strain selectivity in the Phaseolus vulgaris-Rhizobium etli symbiosis through differential analysis of host small RNAs.

Phaseolus vulgaris plants from the Mesoamerican centre of genetic diversification establish a preferential and more efficient root nodule symbiosis with sympatric Rhizobium etli strains. This is mediated by changes in host gene expression, which might occur either at the transcriptional or at the post-transcriptional level. However, the implication of small RNA (sRNA)-mediated control of gene expression in strain selectivity has remained elusive. sRNA sequencing was used to identify host microRNAs (miRNAs) differentially regulated in roots at an early stage of the symbiotic interaction, which were further characterized by applying a reverse genetic approach. In silico analysis identified known and new miRNAs that accumulated to a greater extent in the preferential and more efficient interaction. One of them, designated as Pvu-miR5924, participates in the mechanisms that determine the selection of R. etli strains that will colonize the nodules. In addition, the functional analysis of Pvu-miR390b verified that this miRNA is a negative modulator of nodule formation and bacterial infection. This study not only extended the list of miRNAs identified in P. vulgaris but also enabled the identification of miRNAs that play relevant functions in nodule formation, rhizobial infection and the selection of the rhizobial strains that will occupy the nodule.

Morphological Diversity and Taxonomic Importance of Fruits and Seeds of the Genus Spigelia (Loganiaceae) in Mexico

Abstract— The genus Spigelia (Loganiaceae) is a Neotropical genus that includes more than 80 species distributed from the United States to Argentina. Systematic studies of the group have rarely considered the carpological characters, so their taxonomic importance has not been analyzed in detail. The aim of this study is to analyze the morphological characteristics of these organs to provide more information for a better species separation and for a more robust infra-generic classification. We provide a detailed description of Spigelia fruits and seeds of the Mexican species since the country represents one of its main centers of diversification. Fruits and seed samples from 54 individuals across 14 species were measured and photographed to describe each one, maintaining as much detail as possible. With the morphological matrix a DFA, PCA, and a dendrogram using the NJ method was performed. The fruits and seeds of the Mexican Spigelia species proved to be taxonomically useful, allowing the differentiation of four main clusters of species separated by the size of the analyzed structures in the three analyses (DFA, PCA, NJ). The results show the variation in size and shape of the structures analyzed, which shows the taxonomic importance of fruits and seeds of the genus Spigelia. Our work represents an advance in the detailed knowledge of structures, which are rarely considered in the descriptions, and which allows us to have a separation of species. A taxonomic treatment and photographs of the fruits and seeds are also included.

Nodulation competitiveness and diversification of symbiosis genes in common beans from the American centers of domestication

Phaseolus vulgaris (common bean), having a proposed Mexican origin within the Americas, comprises three centers of diversification: Mesoamerica, the southern Andes, and the Amotape-Huancabamba Depression in Peru-Ecuador. Rhizobium etli is the predominant rhizobium found symbiotically associated with beans in the Americasalthough closely related Rhizobium phylotypes have also been detected. To investigate if symbiosis between bean varieties and rhizobia evolved affinity, firstly nodulation competitiveness was studied after inoculation with a mixture of sympatric and allopatric rhizobial strains isolated from the respective geographical regions. Rhizobia strains harboring nodC types α and upgamma, which were found predominant in Mexico and Ecuador, were comparable in nodule occupancy at 50% of each in beans from the Mesoamerican and Andean gene pools, but it is one of those two nodC types which clearly predominated in Ecuadorian-Peruvian beans as well as in Andean beans nodC type upgamma predominated the sympatric nodC type δ. The results indicated that those beans from Ecuador-Peru and Andean region, respectively exhibited no affinity for nodulation by the sympatric rhizobial lineages that were found to be predominant in bean nodules formed in those respective areas. Unlike the strains isolated from Ecuador, Rhizobium etli isolated from Mexico as well from the southern Andes was highly competitive for nodulation in beans from Ecuador-Peru, and quite similarly competitive in Mesoamerican and Andean beans. Finally, five gene products associated with symbiosis were examined to analyze variations that could be correlated with nodulation competitiveness. A small GTPase RabA2, transcriptional factors NIN and ASTRAY, and nodulation factor receptors NFR1 and NFR5- indicated high conservation but NIN, NFR1 and NFR5 of beans representative of the Ecuador-Peru genetic pool clustered separated from the Mesoamerican and Andean showing diversification and possible different interaction. These results indicated that both host and bacterial genetics are important for mutual affinity, and that symbiosis is another trait of legumes that could be sensitive to evolutionary influences and local adaptation.

Fossil Capsular Valves ofKoelreuteria(Sapindaceae) from the Eocene of Central Tibetan Plateau and Their Biogeographic Implications

Premise of research. Koelreuteria encompasses three extant species that are discontinuously distributed in East Asia and the Fiji Islands. Koelreuteria had a wide distribution in the Northern Hemisphere during the Paleogene, with the first known fossil record being from the early Eocene of western North America. This study reports early fossil occurrences of Koelreuteria in Asia with a detailed morphological investigation and considers the history of its biogeographical dispersal in light of these finds.Methodology. Four capsular valve fossil species of Koelreuteria are recognized from the early middle Eocene of the Niubao Formation at the Jianglang site (present altitude 4850 m), Bangor County, central Tibetan Plateau, China. They are compared with previous fossil occurrences using existing literature and herbarium records of extant material.Pivotal results. We describe a new species, Koelreuteria kvacekii P.-R. Chen, C. Del Rio & T. Su sp. nov., characterized by its oblate capsular valve, lobed apex, and cordate base of the valve, as well as one or two suborbicular seeds per locule. Other material is assigned to species previously described from other locations, extending the geographic and stratigraphic ranges for K. miointegrifoliola, K. allenii, and K. lunpolaensis.Conclusions. Fossil records of Koelreuteria and other co-occurring plants evidence a subtropical climate in central Tibet during the middle Eocene, contrasting with the present cold and dry climate in this region. These are the earliest fossil records of Koelreuteria from what is now the Tibetan Plateau. It seems that the Tibetan region served as an early diversification center for Koelreuteria during the Paleogene in Asia. All species of this flora disappeared locally because of the formation of the Tibetan Plateau by the Neogene.

The species of Oxytropis DC. of section Gloeocephala Bunge (Fabaceae) from Northeast Asia: genetic diversity and relationships based on sequencing of the intergenic spacers of cpDNA and ITS nrDNA.

Phylogenetic relationships within Oxytropis DC. sect. Gloeocephala Bunge from Northeast Asia were studied using plastid intergenic spacers (psbA-trnH + trnL-trnF + trnS-trnG) and ITS nrDNA. Populations of O. anadyrensis Vass., O. borealis DC., O. middendorffii Trautv., O. trautvetteri Meinsh., and O. vasskovskyi Jurtz. were monomorphic or characterised by a low level of chloroplast genetic diversity (h varied from 0.143 to 0.692, and π from 0.0001 to 0.0005). Presumably, the low genetic diversity was a result of the severe bottlenecks during Pleistocene glaciation-interglacial cycles. Twenty chlorotypes were identified; species studied had no shared chlorotypes. Chlorotypes of O. anadyrensis, O. borealis, and O. middendorffii formed two lineages each, while the chlorotypes of O. trautvetteri and O. vasskovskyi formed one separate lineage each in the phylogenetic network. There were specific diagnostic markers of cpDNA in each lineage, excluding O. vasskovskyi. The presence of a species-specific diagnostic marker in O. trautvetteri and specific markers in two lineages of O. anadyrensis support circumscribing these taxa as independent species. Regarding ITS nrDNA polymorphism, five ribotypes were detected. The differences revealed in plastid and nuclear genomes of Oxytropis sect. Gloeocephala confirmed that the Asian sector of Megaberingia was the main centre of diversification of arctic legumes.

Transgene Flow: Challenges to the On-Farm Conservation of Maize Landraces in the Brazilian Semi-Arid Region.

Brazil is one of the largest global producers of genetically modified crops and a center of origin and diversification of relevant species for agriculture and food. Transgenic monocultures occupy around 50 million hectares, whereas smallholder farmers, indigenous people, and traditional communities are responsible for in-situ/on-Farm conservation of local genetic resources. Based on 15 years of expertise in regulating GMOs and in cross-institutional agrobiodiversity conservation projects, this article discusses the challenges regarding the coexistence of these two agricultural models based on transgene flow detection in maize landraces. As part of a broad and unique participatory transgene-flow-monitoring process, 1098 samples of maize landraces were collected in the Brazilian Semi-arid Region between 2018 and 2021 and analyzed using immunochromatographic strips. The tests revealed 34% of samples with presence of GM proteins. It is concluded that the biosafety standards in force in Brazil do not allow the assurance of on-Farm conservation of maize. The sectors that contribute to agrobiodiversity conservation and do not benefit from using GM seeds are taking on the burden of this process. Transgene flow can be reduced by approving and enforcing more effective coexistence rules that consider maize landraces crop areas also as seed-producing areas added to full disclosure of commercial seeds origin.

Genetic differentiation and evolutionary history of two medicinal gentians (Gentiana stipitata Edgew. and Gentiana szechenyii Kanitz) in the Qinghai-Tibet Plateau

Understanding how alpine medicinal plants responded to environmental changes in the past may improve our ability to predict and mitigate the threats posed by global warming. The region of the Qinghai-Tibet Plateau (QTP) acted as a biogeographic source area and centre of diversification for Gentiana, but there, the genetic divergence and evolutionary processes underlying this diversification are still poorly understood. Focusing on two medicinal Gentiana species (Gentiana stipitata and G. szechenyii) in the QTP region, we assessed their genetic structure, demographic history and range shift to explore their genetic differentiation and evolutionary processes. Using both nuclear and plastid markers, high level of genetic differentiation was observed in both gentians. Both species showed signatures of recent population expansion. Furthermore, hybridization between G. stipitata and G. szechenyii was detected in one population. Species distribution modelling showed that both species continuously expanded range from the Last Interglacial to the present day. Divergence time estimates suggested that the onset of intraspecific diversification in the two gentians both occurred in the Late Miocene and the Pliocene. The results indicated that their intraspecific divergence should be related to topographical complexity and geological features of the Hengduan Mountains as well as geographical isolation in glaciations. This study outlines the patterns of genetic structure in two medicinal gentians, explores how these patterns are shaped, and provides insights into conservation management of medicinal gentians in the QTP region.