Evaluation of genetic diversity in Sulla coronaria from different geographical populations in Tunisia by inter simple sequence repeat (ISSR)

Five oligonucleotides generating 116 markers complementary to simple sequence repeats were used in order to characterize wild and cultivated ecotypes of Sulla coronaria and assess genetic diversity suitable in breeding programs. While analysing populations, a large genetic variability was revealed and supported by the preferentially allogamous mating system of the species. Moreover, the highest level of intra-population variations (Hpop/Hsp = 69.9) either of wild or cultivated accessions have been strongly evidenced by a significant adaptation to variety of habitats. In addition, the structure of populations was independent from the bioclimatic stages and was not affected by environmental factors as shown by the non correlation between the geographic and the Nei and Li’s genetic distances (r= 0.461 and p=0.068>0.05). The unweighted pair group method with arithmetic mean (UPGMA) genetic relationships showed that some local spontaneous accessions characterised by an orthotropic port (Jebel Zit and Beja) were also molecularly similar to other cultivars.Key words: Sulla coronaria, wild and cultivated forms, intra and inter-populations variability, microsatellites (ISSRs), bioclimatic stages

Influence of climate variation on phenolic composition and antioxidant capacity of Medicago minima populations

peer reviewedMedicago minima is a pasture legume that grows almost all over the world. In Tunisia, it occupies various climatic environments and is considered the most abundant annual Medicago plant. However, this species is unconsumed and unused by humans. This study aimed to explore the phytochemical characteristics of Medicago minima selected from diferent provenances in Tunisia and subsequently investigate the infuence of environmental factors on their phenolic composition and antioxidant activity. Therefore, a calorimetric method and DPPH tests provided the total phenolic and totalfavonoid contents and antioxidant potential in roots, stems, leaves and seeds. High performance liquid chromatography (HPLC) identifed and quantifed four phenolic acids and three favonoids in the studied organs. Roots and leaves showed the greatest phenolic compound content and had high antioxidant activity. Rutin and syringic acid (leaves) represent a characteristic for this species. For each organ, principal component analysis of phenolic profles showed that the root’s phenolic composition could be an indication of the plant adaptation to even small changes in its environments. Plants originating from a cold climate, higher altitude or semi-arid environment had the highest phenolic compound contents in their organs. Our fndings provide useful information for the exploitation of the phenolic compounds in these weeds for the development of environmental sustainability

Screening for Astragalus hamosus Triterpenoid Saponins Using HPTLC Methods: Prior Identification of Azukisaponin Isomers

International audienceDue to their particular structural characteristics, the extraction and isolation of saponins from plants present a serious challenge. In this study, specific extraction protocols were first implemented to extract the secondary metabolites from Astragalus hamosus and, more precisely, the saponins. Subsequent purification of the extracts was based on a single chromatographic technique, high-performance thin-layer chromatography, applying two development systems: a one-step system that separated molecules according to their polarity and a multiple development system that made it possible to detect the triterpenoid saponins, azukisaponin or soyasapogenol at a retarded Rf of 0.2. The difficulties of detecting the Astragalus hamosus saponins encountered during the extraction and purification of the extracts have been highlighted and the strategy carried out to isolate the saponins has been discusse

Variation of Bio-Morphometric Traits and Antioxidant Compounds of <i>Brassica oleracea</i> L. Accessions in Relation to Drought Stress

Drought tolerance of Brassica crops can be genetically improved by establishing plant ideotypes with improved yield responses associated with agronomic traits and biochemical markers. The objective of this study was to compare 20 Brassica oleracea L. accessions grown under two different water treatments (100% and 35% reintegration of evapotranspiration by irrigation) to select potential tolerant genotypes for organic cultivation based on several agronomic and biochemical parameters measured in response to drought stress. Significant differences were registered for the genotype and the irrigation regime and for their interaction (p < 0.0001 ***). A principal component analysis was performed to summarize the correlations among the analyzed phytochemicals and the stressed and not stressed genotypes and highlighted the importance of the antioxidant compounds as stress biomarkers. The present results showed that drought significantly reduces growth parameters and increases the amount of ascorbic acid and polyphenols compared to the irrigated control. Additionally, the results show that antioxidant metabolism increased by drought in some genotypes while others maintained a good biomass production by increasing the value of growth parameters considered. Based on the average sum of ranks (ASR) of morpho-physiological and biochemical parameters, the genotypes CR, CC, and BH were determined to be the most drought tolerant, whereas CI5, BU, and CV1 were determined to be the most susceptible. Due to the potential of these genotypes, further molecular and cellular research will be carried out to identify the genetic marker associated with the water stress response

The Effect of Water Stress on the Glucosinolate Content and Profile: A Comparative Study on Roots and Leaves of <i>Brassica oleracea</i> L. Crops

Drought is one of the major challenges of global crop production, and its severity is increasing because of climate change. This abiotic stress is an important target for Brassica species, which are generally grown in arid and semi-arid climates. This study was conducted to investigate the effects of water deficit on a set of accessions belonging to the Brassica core collection of the EU H2020 BRESOV project, represented by Brassica oleracea L. crops and Brassica oleracea complex species (n = 9). In particular, the variation in the amount and profile of the glucosinolates (GLSs) compounds was analyzed on the root and the leaf tissues. The plant morphometric traits and GLSs amount and profile were detected for the plants grown in cold greenhouse in Catania (Sicily) during the autumn–winter season for ten weeks. The results showed a wide qualitative and quantitative variation among the Brassica accessions. The GLSs profile varied qualitatively and quantitively among both genotypes and portions of the plants (hypogenous-root and epigeous-leaf). Plants grown under drought stress, for the last two weeks of the growing cycle under consideration, showed a higher amount of GLS in their leaves (190.1 ± 8.9 µmol. g−1 d.w.) compared to their roots (17.3 ± 1.9 µmol. g−1 d.w.). Under water stress conditions, the highest increase in the glucosinolate amount was detected in broccoli (the accession BR1) with 85.4% and in cauliflower (the accession CV1) with 72.8% in the roots and leaves, respectively. Positive correlations were found between the major leaf and root GLSs identified. The selection of chemotypes allows for an important time reduction during the breeding programs after crossing accessions with the specific profiles of glucosinolates

Integrated analysis for identifying <i>Portulaca oleracea</i> and its sub-species based on chloroplastic and nuclear DNA barcoding

<p>The taxonomy of <i>Portulaca oleracea</i> has been considered as being complex since the aggregate is composed of many subspecies or a group of micro-species based on seed-coat characters, seed size, and chromosome number. In order to enlarge the background of the extent of genetic variability between and within Tunisian <i>P. oleracea</i> accessions, a combined morphological and molecular approach was adapted, in the present survey. The morphological analyses of the spontaneous Tunis population display high intra population variability characterized by two distinct morphotypes corresponding to the botanical forms (wild and cultivated plant). Furthermore, the molecular approach based on sequences data related to chloroplastic and ribosomal DNA, was used to understand this variability. The obtained results highlighted the greater molecular variability of this plant and allowed to segregate between morphotypes and genotypes of <i>Portulaca</i>. Mostly, this work shows the important contribution of DNA barcoding approach in resolving low-level-taxonomy problems to distinguish between natural populations and varieties.</p