Evaluation of genetic diversity among Tunisian grapevines by RAPD markers

Thirty-three native Tunisian grapevine varieties (Vitis vinifera L.), previously analysed with biochemical tools, were surveyed with RAPD markers, Eleven primers amplified 54 clear and unambiguous markers. Five groups of varieties were clearly resolved by UPGMA cluster analysis. These results allowed the discrimination of groups of varieties that could not be discriminated by biochemical analyses. In addition, the dendrogram obtained could be shown being independent from both the phenotypic characters and the origin of the accessions.

The use of phosphinothricin resistance as selectable marker for genetic transformation of grapevine

A transformation procedure with the bar gene as a selectable marker was established via Agrobacterium-mediated transformation using strain LBA4404 harbouring the vector pPZP200-bar-gus-intron. Recreation of embryogenic cells from transformation stress in PPT free medium for four weeks improved viability and number of GUS expressing cells. Concentration of 2.5 mg·l-1 PPT yielded highest selection efficiency. Transgenicity of the regenerated grapevine plants was confirmed by histochemical GUS assay and bar specific PCR and RT/PCR. With the described procedure, 20 % of regenerated embryos could be converted into transgenic grapevines.

CuO–water mhd mixed convection analysis and entropy generation minimization in double-lid–driven u-shaped enclosure with discrete heating

The present study explores magnetic nanoliquid mixed convection in a double lid–driven U-shaped enclosure with discrete heat-ing using the lattice Boltzmann method (LBM) numerical method. The nanoliquid thermal conductivity and viscosity are calculated using the Maxwell and Brinkman models respectively. Nanoliquid magnetohydrodynamics (MHD) and mixed convection are analyzed and entropy generation minimisation has been studied. The presented results for isotherms, stream isolines and entropy generation describe the interaction between the various physical phenomena inherent to the problem including the buoyancy, magnetic and shear forces. The operating parameters’ ranges are: Reynolds number (Re: 1–100), Hartman number (Ha: 0–80), magnetic field inclination (γ: 0°–90°), nanoparticles volume fraction (ϕ: 0–0.04) and inclination angle (α: 0°–90°). It was found that the and the total entropy generation augment by increasing Re, ϕ: and γ. conversely, an opposite effect was obtained by increasing Ha and α. The optimum magnetic field and cavity inclination angles to maximum heat transfer are γ = 90° and α = 0

Preservation of endangered Tunisian grapevine cultivars using embryogenic cultures

The preservation of embryogenic lines derived from several endangered local grapevine cultivars was studied. Embryogenic calluses were obtained from immature anthers of eight cultivars, sampled on both fruity-cuttings and field grown vines. Anthers at the 'separated flower' stage, derived from fruity-cuttings, resulted in an increased induction of somatic embryogenesis, compared to those derived from the The preservation of embryogenic lines derived from several endangered local grapevine cultivars was studied. Embryogenic calluses were obtained from immature anthers of eight cultivars, sampled on both fruity-cuttings and field grown vines. Anthers at the 'separated flower' stage, derived from fruity-cuttings, resulted in an increased induction of somatic embryogenesis, compared to those derived from the 15.6% and 34.8% in 'Kahli Kerkennah' and 'Muscat Raf-raf' cultivars, respectively. Although, morphological diversifications of pro-embryogenic calluses (several necrosis and spontaneous maturation) were observed on the induction mediumafter 5 subcultures. The reduction of 2,4-D and TDZ levels to 4.52 μM and 2.89 μM respectively, induced granular and yellowish embryogenic material. Thus, Chée and Pool (1987) (CP) enriched with 4.52 μM of 2,4-D and 2.89 μM of TDZ revealed to be the most appropriate for long-term maintenance. In fact, all the cultivars presented high and regular embryo maturation rates after 12, 24, 36 and 48 months of cultivation on this medium, under light conditions. After 4 years, they still exhibit high germination and regeneration abilities. Germination of somatic embryos was achieved on Murashige and Skoog (1962) basal-medium, with rates ranging from 69% to 96%. Only 5% of somatic embryos were concerned by morphological variations. The regenerated plantlets presented a normal phenotype under controlled greenhouse conditions, compared to mother plants

Crystal structure of nanocrystalline Pr5Co19 compound and its hydrogen storage properties

International audienc

Origin and genetic diversity of Tunisian grapes as revealed by microsatellite markers

Contact: [email protected] audienceTen SSR loci, previously developed for grapevine, were analyzed to evaluate the genetic variability, cultivar relatedness, and parentage in a collection of 61 autochthonous Vitis vinifera cultivars from Tunisia. The number of alleles per locus ranged from 6 to 11, while the number of genotype patterns varied between 10 and 21. The expected heterozygosity varied between 0.621 and 0.855 and the observed heterozygosity was higher than 0.9 at 4 loci (VVMD28, VVMD5, VVIP31 and VVS2) indicating that the SSRs were highly informative. Cluster analysis using unweighted pair group method with arithmetic averaging (UPGMA) suggested 14 groups among Studied cultivars and 53 grapevine denominations Out Of 61 Were unequivocally distinguished, with all accessions showing at least one-specific combination of alleles. On the other hand, in order to overcome the existing confusion in Tunisian grapevine nomenclature, of the analyzed homonymous pairs of cultivars, only 'Balta 2' and 'Balta 3' have shown identical allelic profiles, consistent with their being the same genotype. Hence, nomenclature distinction is meaningless and only one denomination should be retained. Due to the high overall power of exclusion (Q) (greater than 99.99%) and to the absence of null alleles, the set of microsatellite loci used is appropriate to determine parentage in Tunisian grapevines beyond any reasonable doubt. The analysis of fingerprints indicated that the Tunisian grape vines have evolved through out crossing between five possible parents: Balta 1, Beldi Baddar, Beldi Rafraf, Belch Local Rafraf and khedhiri

Molecular characterization and evolutionary pattern of the 9-cis-epoxycarotenoid dioxygenase NCED1 gene in grapevine

This study provides the first analysis of the level and patterns of nucleotide polymorphism of the NCED1 gene in grapevine (Vitis vinifera L.). A total of 123 sequences of the gene were analyzed to give a sample of 50 wild accessions and 73 cultivars. A high single nucleotide polymorphism and haplotype diversity was revealed in the cultivars studied, especially Tunisian germplasms which present an important and diverse reservoir of genetic diversity for grape breeding and conservation. The haplotype distribution highlights two origins of the cultivars studied: one may be related to primary grapevine gene pool domestication while the second seems to be more recent. Thus, besides domestication, gene introgression has also played a role in shaping the current varietal landscape of grape cultivars. Higher nucleotide and haplotype polymorphism was recorded for cultivars. This was accompanied by a higher recombination rate in cultivated grapevines for this gene, a recent selective sweep in wild samples and a balancing selection in cultivars. The conservation of genetic diversity of the endangered wild germplasm is important to ensure that the wild population can be used in future breeding programs of the domesticated cultivars. The high number of alleles discovered can be used as a valuable source for association studies between allele frequencies and phenotypic variations in this gene. In addition to natural selection, molecular evidence shows that genetic variation in this locus appears to be shaped by a combination of mutation and recombination events