RESUMEN
PREMISE: Endoreduplication, nonheritable duplication of a nuclear genome, is widespread in plants and plays a role in developmental processes related to cell differentiation. However, neither ecological nor cytological factors influencing intraspecific variation in endoreduplication are fully understood. METHODS: We cultivated plants covering the range-wide natural diversity of diploid and tetraploid populations of Arabidopsis arenosa in common conditions to investigate the effect of original ploidy level on endoreduplication. We also raised plants from several foothill and alpine populations from different lineages and of both ploidies to test for the effect of elevation. We determined the endoreduplication level in leaves of young plants by flow cytometry. Using RNA-seq data available for our populations, we analyzed gene expression analysis in individuals that differed in endoreduplication level. RESULTS: We found intraspecific variation in endoreduplication that was mainly driven by the original ploidy level of populations, with significantly higher endoreduplication in diploids. An effect of elevation was also found within each ploidy, yet its direction exhibited rather regional-specific patterns. Transcriptomic analysis comparing individuals with high vs. low endopolyploidy revealed a majority of differentially expressed genes related to the stress and hormone response and to modifications especially in the cell wall and in chloroplasts. CONCLUSIONS: Our results support the general assumption of higher potential of low-ploidy organisms to undergo endoreduplication and suggest that endoreduplication is further integrated within the stress response pathways for a fine-tune adjustment of the endoreduplication process to their local environment.
Asunto(s)
Arabidopsis , Arabidopsis/genética , Diploidia , Endorreduplicación/genética , Ploidias , TetraploidíaRESUMEN
Hybrid seed inviability (HSI) is an important mechanism of reproductive isolation and speciation. HSI varies in strength among populations of diploid species but it remains to be tested whether similar processes affect natural variation in HSI within ploidy-variable species (triploid block). Here we used extensive endosperm, seed and F1 -hybrid phenotyping to explore HSI variation within a diploid-autotetraploid species. By leveraging 12 population pairs from three ploidy contact zones, we tested for the effect of interploidy crossing direction (parent of origin), ploidy divergence and spatial arrangement in shaping reproductive barriers in a naturally relevant context. We detected strong parent-of-origin effects on endosperm development, F1 germination and survival, which was also reflected in the rates of triploid formation in the field. Endosperm cellularization failure was least severe and F1 -hybrid performance was slightly better in the primary contact zone, with genetically closest diploid and tetraploid lineages. We demonstrated overall strong parent-of-origin effects on HSI in a ploidy variable species, which translate to fitness effects and contribute to interploidy reproductive isolation in a natural context. Subtle intraspecific variation in these traits suggests the fitness consequences of HSI are predominantly a constitutive property of the species regardless of the evolutionary background of its populations.
Asunto(s)
Arabidopsis , Diploidia , Arabidopsis/genética , Hibridación Genética , Poliploidía , Aislamiento Reproductivo , Tetraploidía , TriploidíaRESUMEN
PREMISE: Whole genome duplication is a major evolutionary event, but its role in ecological divergence remains equivocal. When populations of different ploidy (cytotypes) overlap in space, "contact zones" are formed, allowing the study of evolutionary mechanisms contributing toward ploidy divergence. Multiple contact zones per species' range are often described but rarely leveraged as natural replicates. We explored whether the strength of niche differentiation of diploid and autotetraploid Arabidopsis arenosa varies over distinct contact zones and if the frequency of triploids decreases from seedling to adult stage. METHODS: We characterized ploidy composition and habitat preferences in 264 populations across three contact zones using climatic niche modeling. Ecological differences of cytotypes were also assessed using local vegetation surveys at 110 populations within two contact zones, and at the finer scale within five mixed-ploidy sites. This was complemented by flow cytometry of seedlings. RESULTS: We found no niche differences between diploid and tetraploid populations within contact zones for either climatic or local environmental variables. Comparisons of cytotypes within mixed-ploidy sites found weak niche differences that were inconsistent in direction. Triploid individuals were virtually absent (0.14%) in the field, and they were at a similarly low frequency (0.2%) in ex situ germinated seedlings. CONCLUSIONS: This study demonstrates the strength in investigating different spatial scales across several contact zones when addressing ecological niche differentiation between ploidies. The lack of consistent habitat differentiation of ploidies across the scales and locations supports the recently emerging picture that processes other than ecological differentiation may underlie ploidy coexistence in diploid-autopolyploid systems.
Asunto(s)
Arabidopsis , Diploidia , Arabidopsis/genética , Humanos , Ploidias , Poliploidía , TetraploidíaRESUMEN
Natural polyphenols are a wide class of secondary plant metabolites and represent an abundant antioxidant component of human diet. An important, but often neglected group of natural polyphenols, are tannins. This review offers a general description of chemistry of both hydrolysable and condensed tannins (proanthocyanidins), the mechanisms of their antioxidation action, like free radical scavenging activity, chelation of transition metals, inhibition of prooxidative enzymes and lipid peroxidation. The mechanisms of action of antibacterial, antiviral, anticarcinogenic, cardiovascular system preventing, and antiinflammatory effects as well as the absorption, metabolic fate and positive in vivo effects of tannins are enclosed.
Asunto(s)
Antioxidantes/farmacología , Salud , Taninos Hidrolizables/farmacología , Animales , Antiinfecciosos/química , Antiinfecciosos/farmacología , Antiinfecciosos/uso terapéutico , Antiinflamatorios no Esteroideos/química , Antiinflamatorios no Esteroideos/farmacología , Antiinflamatorios no Esteroideos/uso terapéutico , Anticarcinógenos/química , Anticarcinógenos/farmacología , Anticarcinógenos/uso terapéutico , Antioxidantes/química , Antioxidantes/uso terapéutico , Peroxidasa de Rábano Silvestre/antagonistas & inhibidores , Humanos , Taninos Hidrolizables/química , Taninos Hidrolizables/uso terapéutico , Peroxidación de Lípido/efectos de los fármacos , Lipooxigenasa/efectos de los fármacos , Óxido Nítrico Sintasa/antagonistas & inhibidoresRESUMEN
A simple and sensitive high-performance liquid chromatography method for the determination of four Leuzea carthamoides flavonoids, namely eriodictyol, patuletin, eriodictyol-7-beta-glucopyranoside, and 6-hydroxykaempferol-7-O-(6"-O-acetyl-beta-D-glucopyranoside), is presented. Using this method, quantitative composition of flavonoids ranged from 0.011% to 0.574% in dried plant material was determined. This method could be used in the future for the quantitative evaluation of major phenolic compounds in L. carthamoides.
Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Flavonoides/análisis , Leuzea/química , Cromonas/análisis , Flavanonas/análisisRESUMEN
In recently, there has been a great interest in natural antioxidants as bioactive components of food, nutraceuticals or potential drugs against several diseases. In our study, 88 extracts from various parts of plants from European Asteraceae and Cichoriaceae were assayed for radical scavenging activity by means of DPPH (1,1-diphenyl-2-picryl hydrazyl radical) test using the SIA (Sequential injection analysis) method developed for this purpose in our laboratory. DPPH radical scavenging activity of all tested plant extracts was evaluated according to the IC(50) parameter. 29 extracts exhibited IC(50) value lower than 0.1 mg/mL. The leaves of Leuzea carthamoides (IC(50) = 0.046 mg/mL) were chosen as the most promising sample for a subsequent phytochemical study, which resulted in isolation of seven natural compounds, namely, 4',5,7-trihydroxy-6-methoxyflavone (hispidulin) (1), 5, 7, 3', 4'- tetrahydroxyflavanone (eriodictyol) (2), 3',4',5,7-pentahydroxy-6-methoxyflavonol (patuletin) (3), eriodictyol-7-beta-glucopyranoside (4), 6-hydroxykaempferol-7-O-(6''-O-acetyl-beta-D-glucopyranoside) (5), 4-hydroxybenzoic acid (6) and 3,4-dihydroxybenzoic acid (protocatechuic acid) (7). Antioxidant activity of the isolated compounds was evaluated by DPPH test and ferric reducing antioxidant power (FRAP) test and compared with trolox and quercetin. Both tests evaluated the flavonoid (5) as the most active antioxidant. This result was confirmed by comparison with known data concerning the structure/activity relationships of flavonoids.
Asunto(s)
Antioxidantes/química , Antioxidantes/farmacología , Asteraceae/química , Productos Biológicos/química , Productos Biológicos/farmacología , Leuzea/química , Rhodophyta/química , Compuestos de Bifenilo , Cromanos/química , Cromanos/aislamiento & purificación , Evaluación Preclínica de Medicamentos , Europa (Continente) , Hidrazinas , Estructura Molecular , Picratos , Extractos Vegetales/química , Extractos Vegetales/aislamiento & purificación , Extractos Vegetales/farmacología , Quercetina/química , Quercetina/aislamiento & purificación , Relación Estructura-ActividadRESUMEN
Plants and their secondary metabolites, including flavonoids, exhibit a wide range of biological effects. Consequently, natural substances are receiving an increased attention in medicinal research. Owing to these facts, in vitro antiplatelet activity of ethanol summary extract and four flavonoids from Leuzea carthamoides was determined in human platelet-rich plasma. Arachidonic acid (AA), adenosine diphosphate (ADP), collagen (COL), and thrombin were used as agonists of platelet aggregation. The summary extract showed a significant inhibition of the aggregation induced by COL and ADP. Of the tested flavonoids, eriodictyol (1) and patuletin (2) influenced COL- and AA-induced aggregation. Their IC(50) values are presented. Flavonoid glycosides eriodictyol-7-beta-glucopyranoside (3) and 6-hydroxykaempferol-7-O-(6''-O-acetyl-beta-D[small cap]-glucopyranoside) (4) were found to be weak antiplatelet agents. These results confirmed the fact that glucosylation decreases the antiplatelet activity. Quantitative composition of tested flavonoids in L. carthamoides extract was also determined. Though two of the tested flavonoids inhibited platelet aggregation, further evaluation of L. carthamoides, in order to discover other antiplatelet active compounds and possible adverse health effects, is needed.