Genetic diversity and population structure of Teucrium polium (Lamiaceae) in Tunisia

The impact of environmental and climatic variables on genetic diversity and plant functional traits of the endangered tuberous orchid (Orchis mascula L.)

Understanding how environmental factors shape patterns of genetic and phenotypic variations in a species is necessary for conservation and plant breeding. However, these factors have not yet been completely understood in tuberous orchid species used to make 'Salep', an important ingredient in traditional medicine and beverages in middle eastern countries and India. In many areas, increasing demand has pushed species to the brink of extinction. In this study, 198 genotypes from 18 populations of the endangered species Orchis mascula L. spanning a large-scale climatic gradient in northern Iran were used to investigate patterns of genetic diversity and plant functional traits. Populations were sampled from three land cover types (woodland, shrubland, and pastureland/grassland). Plant height, stem length, number of flowers, bulb fresh and dry weight, glucomannan, and starch concentrations showed high variation among populations and were significantly related to land cover type. In general, genetic diversity was high, particularly in those from eastern Hyrcanian; additionally, populations showed a high level of genetic differentiation (G'_st = 0.35) with low gene flow (Nm = 0.46). The majority of genetic differentiation occurred within populations (49%) and land cover types (20%). The population structural analysis using the AFLP marker data in K = 4 showed a high geographical affinity for 198 O. mascula genotypes, with some genotypes having mixed ancestry. Temperature and precipitation were found to shape genetic and phenotypic variation profoundly. Significant isolation by the environment was observed, confirming the strong effect of environmental variables on phenotypic and genetic variation. Marker-trait association studies based on MLM1 and MLM2 models revealed significant associations of P-TGG + M-CTT-33 and E-AGG + M-CGT-22 markers with plant height and glucomannan content. Overall, a combination of large-scale climatic variables and land cover types significantly shaped genetic diversity and functional trait variation in O. mascula populations.

DNA Barcoding, GIS-Facilitated Seed Germination and Pilot Cultivation of Teucrium luteum subsp. gabesianum (Lamiaceae), a Tunisian Local Endemic with Potential Medicinal and Ornamental Value

In the context of plant conservation and sustainable use of unique neglected and underutilized phytogenetic resources, this study focused on the Tunisian local endemic Teucrium luteum subsp. gabesianum (Lamiaceae). Using Geographical Information Systems and online databases, detailed taxon-specific ecological profiling was produced for the first time, which illustrated the temperature and climate conditions in its wild habitats and facilitated the investigation of how temperature affects its seed germination, thus making its cultivation in anthropogenic environments possible. Following the seed propagation first reported herein (77.5−81.25% at temperatures between 15 and 25 °C), species-specific in situ and ex situ conservation efforts or sustainable exploitation strategies can be enabled. This study also reported for the first time how chemical and integrated nutrient management (INM) fertilizers affect the growth and pilot cultivation of its seedlings (INM more advantageous). The firstly-reported herein DNA barcoding may enable its traceability, allowing future product design. The multidisciplinary approach followed has paved the way to bridge important research gaps hindering conservation efforts and/or the sustainable exploitation of this local Tunisian endemic plant to date. Based on the aforementioned results, the feasibility and readiness timescale for its sustainable exploitation was overviewed and re-evaluated herein, upgrading (>two-fold) its potential value for the medicinal-cosmetic, agro-alimentary, and ornamental-horticultural sectors.

Chemical and genetic diversity of two Mediterranean subspecies of Teucrium polium L

Chemical and genetic diversity of Teucrium polium L. subsp. polium from western Algeria and T. polium L. subsp. capitatum from Corsica were investigated. Diversity within and among the two populations of subspecies was assessed according to the chemical composition of their essential oils and the genetic diversity. Chemical analysis was performed using a combination of capillary GC-RI and GC/MS after fractionation using column chromatography. Genetic structures were mapped using three polymorphic genetic markers: two chloroplast markers (RPL32-TRNL and TRNL-F) and ribosomal nuclear markers (ITS region). The statistical analysis showed that both subspecies were clearly distinguished by these chemical and genetic markers. The oil chemical compositions differed qualitatively and quantitatively between the subspecies. Both collective oils were dominated by hydrocarbon compounds however the Algerian sample oils exhibited higher amounts of hydrocarbon sesquiterpenes than those of Corsica (31.2 g/100 g vs. 4.4 g/100 g) while the latter displayed higher amounts of hydrocarbon monoterpenes than the first (59.3 g/100 g vs. 34.3 g/100 g). Neighbor-joining, Maximum likelihood and Bayesian trees constructed from chloroplast markers and nuclear ITS region sequences showed the existence of two groups associated with taxonomic and chemical characteristics. The study indicated that variation in the essential oil composition within subspecies depends on genetic background. The samples of subsp. capitatum from Corsica are a homogeneous group, in contrast to samples of subsp. polium from Algeria which were clustered in two groups. Chemical and genetic diversity of Algerian populations could be explained by geographical isolation of the populations. In addition, the morphological polymorphism observed throughout the colour of flowers could be explained by environmental parameters as well as the soil pH.

Chemical and genetic differentiation of two Mediterranean subspecies of Teucrium scorodonia L

Chemical and genetic diversity of Teucrium scorodonia L. subsp. scorodonia from Corsica and T. scorodonia L. subsp. baeticum from western Algeria were investigated. Diversity within and among the two populations of subspecies was assessed according to the chemical composition of their essential oils, and genetic diversity was evaluated using three polymorphic genetic markers. Chemical analysis was performed using a combination of capillary GC-RI and GC/MS after fractionation using column chromatography. Genetic structures were mapped using two chloroplast markers (RPL32-TRNL and TRNL-F) and ribosomal nuclear markers (ITS region). The statistical analysis showed that the two subspecies were clearly distinguished by these chemical and genetic markers. The chemical composition of oil differed qualitatively and quantitatively between the subspecies. Corsican oil samples contained germacrene B (4.2-8.8%) and γ-elemene (2.6-5.7%), which were not detected in Algerian oil samples. The oils of the scorodonia and baeticum subspecies were dominated by sesquiterpene hydrocarbon compounds (75.6-82.9% and 69.6-79.4%, respectively), but they differed in oxygenated sesquiterpene content (3.1-8.9% and 8.4-20.3%, respectively). Neighbor-joining trees constructed from chloroplast DNA and ITS region sequences showed the existence of two groups associated with taxonomic and chemical characteristics. One group consisted of T. scorodonia subsp. scorodonia and the other of T. scorodonia subsp. baeticum, indicating that variation in the essential oil composition of T. scorodonia subspecies depends more on genetic background than environmental characteristics.

Analysis of the Essential Oil of Teucrium polium ssp. capitatum from the Balkan Peninsula

The chemical composition of the essential oil of the aerial parts of Teucrium polium ssp. capitatum collected during the flowering period from rocky places and dry pastures, (Serbia, Niŝ, Kamenica), and dunes along the sea-side, (Bulgaria, Burgas, Primorsko) has been studied by GC and GC/MS. The identified compounds, 45 for the oil from Serbia and 44 for that from Bulgaria, amounted to 97.3% and 96.4% of the oils, respectively. The dominant constituents of the Serbian oil were sesquiterpenes {59.6%, the most abundant components being germacrene D (31.8%), trans-caryophyllene (8.8%) and bicyclogermacrene (6.2%)}, while monoterpenes accounted for 37.5% {the most abundant components being linalool (14.0%) and β-pinene (10.7%)}. The essential oil from Bulgaria was characterized by a high percentage of monoterpenes, amounting to 62.9% {the most abundant components being β-pinene (26.8%), α-pinene (9.3%) and limonene (6.4%)}, while sesquiterpenes accounted for 33.5% (the most abundant component was germacrene D 17.7%)}.

Genetic structure of the carnivorous plant Pinguicula moranensis (Lentibulariaceae) on the transvolcanic Mexican belt

Most species of Pinguicula present a montane distribution with populations located at high altitudes. In this context, we proposed that populations of Pinguicula species could be genetically differentiated even at a local scale. This study supported that prediction, as a RAPD-based analysis of molecular variance revealed a high degree of genetic structure (Φ (st) = 0.157, P = 0.001) and low gene flow (Nm = 1.0) among four central populations of Pinguicula moranensis in Mexico, with a maximum geographic separation of about 140 km. The four populations also exhibited high levels of genetic diversity (mean Nei's genetic diversity = 0.3716; % polymorphism = 95.45%). The evolutionary implications of the genetic structure found in P. moranensis for other species in the genus are discussed in the context of the naturally fragmented distribution and a set of life history traits shared by most Pinguicula species that could promote geographic isolation and limited gene flow.

Genetic diversity of tufted ducks (Aythya fuligula, Anatidae) in Eastern Europe

The tufted duck (Aythya fuligula, Anatidae) is widespread in the Palaearctic across Northern Eurasia. Birds breeding in Northern and Eastern Europe are highly migratory, while populations from Western Europe are partially migratory or resident. The aim of this study is to explore genetic variation within and between ducks breeding in Latvia and migrants sampled in North West Russia and Belarus. The technique of random amplified polymorphic DNA was applied using five random primers (ol-1, ol-9-12). Genetic variability was measured for all tufted ducks investigated and for different sub-populations from various regions. Individual genetic structure and genetic variability was higher in ducks collected from Latvia. Gene diversity of amplified DNA bands in birds of Latvian origin was 24% with 80% polymorphism. Means of gene diversity and polymorphism for tufted ducks sampled in other countries varied from 12 to 14% and from 27 to 40%, respectively. A high number of unique bands characterized ducks breeding in Latvia. The oligonucleotide primers used in this study were suitable to analyze differences among tufted ducks of different origin. Possible explanations for the variation observed among the studied ducks are discussed.

Chemical and genetic differentiation of Corsican subspecies of Teucrium flavum L

Corsica Island exhibited the particularity to display Teucrium flavum subsp. glaucum and subsp. flavum on the same territory with the same bioclimatic conditions. For the first time, volatile components extracted from aerial parts and genetic diversity of both Corsican T. flavum L. subspecies have been investigated through (i) the characterization of the chemical composition of essential oils and (ii) the study of three polymorphic genetic markers. Chemical analysis were performed using combination of capillary GC/RI, GC-MS after fractionation on column chromatography and the definition of the genetic structure were carried out using two chlororoplast markers (RPL32-TRNL and TRNL-F) and ribosomal nuclear markers (ITS region). According to statistical analysis, both subspecies were clearly distinguished by the chemical and genetic studies. Chemical compositions of oils from both subspecies were qualitatively similar but they differed by the normalized% abundances of their major components; oils from subsp. flavum were dominated by large amounts of hydrocarbon monoterpenes while oils obtained from subsp. glaucum were characterized by higher amounts of oxygenated compounds. The genetic analysis divided T. flavum L. populations in two groups, the first displayed subsp. glaucum populations and the latter group exhibited subsp. flavum populations. The presence of two groups is weakly consistent with chemical differentiation. These data suggest that the differences in the volatile composition of the two T. flavum subspecies depends more on the genetic background and less on environmental factors.