A. Akkak

Università degli Studi di Torino, Torino, Piedmont, Italy

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Publications (15)20.1 Total impact

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    ABSTRACT: Castanea sativa Mill. is an important multipurpose tree species for north-western Italy, and specially for Piedmont Region. The preservation of its germplasm from the ge-netic erosion due to the changes in socio-economic struc-ture of rural areas and specific pathogen attacks is critical. The principal aims of this work were to characterize the chestnut germplasm grown in Piedmont and investigate its genetic structure. Sixty-eight grafted chestnut trees were evaluated using 10 SSRs (simple sequence repeats) loci and 20 morphological descriptors. Thirty-six different ge-notypes were identified; the analysis of the genetic struc-ture of this germplasm revealed that four gene pools contributed to the formation of the population sampled. In general, cultivars tended to group into a main gene pool on the basis of their prevalent use and growing area. These results are substantially in agreement with those of the cluster analysis that was carried out to estimate the genetic relationships among the cultivars. Morphological analyses showed large variation of traits among the in-dividuals, related with the market destination of the nuts and useful for cultivar and clonal selection. Discriminant analysis was applied to find a correlation between genetic and morphological data: nut and leaf shape, nut hairiness and male flower type resulted to be the most discriminant traits associated with the genetic structure. In the end, this work clarified the genetic structure of the cultivated germ-plasm in Piedmont describing the main cultivars of the region, giving useful information for conservation and breeding purposes.
    Tree Genetics & Genomes 04/2013; 9:1017–1030. · 2.40 Impact Factor
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    ABSTRACT: Sequence Tagged Microsatellite Sites (STMSs) and morphological trait markers were used to evaluate 33 rhododendron germplasm for genetic diversity assessment and discrimination power. The average genetic diversity estimates were 0.724 (morphological traits) and 0.174 (STMSs) marker datasets. The Shannon index was higher for morphological traits (1.797) than STMS (0.302). The correlation coefficients obtained by the Mantel matrix correspondence test, which was used to compare the cophenetic matrices for the two markers, showed that estimated values of relationships given for morphological and STMS were not significantly related (p textgreater 0.05). The dataset from STMS, supported by the total probability of identity (1.13 x 10(-9)) and total paternity exclusion probability (0.9999), allowed all accessions to be uniquely identified. In summary, STMS marker proved to be an efficient tool in assessing the genetic variability among old broad leaf rhododendron genotypes. The pattern of variation appeared to be consistent, and it can be used for germplasm conservation and management for restoration of historical genetic resources. (C) 2010 Elsevier B.V. All rights reserved.
    Scientia Horticulturae 06/2010; 125(3):469-476. · 1.50 Impact Factor
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    ABSTRACT: Forty one simple sequence repeats were isolated from two microsatellite enriched libraries of date palm (Phoenix dactylifera L.). After screening, 17 selected microsatellite loci were characterized and evaluated on a set of 31 cultivars and clones from Algerian and Californian germplasm. All primer pairs produced an amplification product of the expected size and detected high polymorphism among the analysed samples. These nuclear simple sequence repeat (SSR) markers are expected to be a very effective tool for evaluating genetic diversity in date palm germplasm. Acrosstaxa amplification showed the usefulness of most SSR markers in 14 other species across the genus Phoenix.
    Biologia Plantarum 02/2009; 53(1):164-166. · 1.69 Impact Factor
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    ABSTRACT: Establishing genetic origin of food products allows verification of the authenticity of valuable foods and discourages adulteration with material of lower cost and value. This is particularly important for food products that have obtained European recognition. The use of molecular markers could be a solution for species and cultivar identification and for the genetic traceability. The development of efficient DNA-extraction protocols is an essential step for the procedure. In this work, a method for total DNA isolation was developed for hazelnut, almond and walnut seeds. The efficiency and reliability of the method was tested by assessing quantity and quality of the extracted DNA, and by Polymerase Chain Reaction (PCR) amplification, using two decamer primers and three universal primer pairs designed on the chloroplast DNA. The success of amplifications confirmed the presence of both nuclear and chloroplast DNA in the extracted sample.PRACTICAL APPLICATIONSCultivar identification of nuts, based on morphological traits only, is often difficult, and adulterations with seeds of lower cost and quality are easy, above all when they are sold as shelled kernel, as is common for hazelnut. The genetic identification of cultivars is nowadays a routine practice, because of the development of DNA-typing techniques based on molecular markers. An efficient DNA-extraction procedure for hazelnut, almond and walnut seeds is a preliminary step required for enabling the recognition of the cultivar of origin of the nuts and fighting commercial frauds. It will also be useful in marker-assisted selection, applied in breeding.
    Journal of Food Quality 07/2008; 31(4):549 - 557. · 0.76 Impact Factor
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    A Akkak, P Boccacci, R Botta
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    ABSTRACT: The grapevine (Vitis vinifera L.) is one of the most widely grown fruit plants, with table grapes accounting for at least 20% of the total world production. A few traditional table grape cultivars have achieved great international prominence. Among the most important cultivars is 'Cardinal', a historical Californian grapevine obtained by E. Snyder and F. Harmon in 1939 by crossing 'Flame Tokay' (syn. 'Ahmer Bou Amer') with 'Ribier' (syn. 'Alphonse Lavallée') at the Horticultural Field Station of Fresno, Calif.. In the course of DNA typing grapevine varieties collected in Algeria and other Mediterranean countries, we found, surprisingly, that 'Cardinal'could not result from this cross. Here, we present molecular genetic evidence that 'Cardinal' has no parentage relationship with 'Flame Tokay'. We also show, for the first time, that 'Flame Tokay' is a mutant version, at the VVS5 microsatellite locus, of the table grape 'Ahmer Bou Amer', which is considered its synonym.
    Genome 04/2007; 50(3):325-8. · 1.67 Impact Factor
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    P Boccacci, A Akkak, R Botta
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    ABSTRACT: In this work, 78 hazelnut (Corylus avellana L.) cultivars from various germplasm repositories were studied at 16 simple sequence repeat (SSR) loci in order to identify the genotypes and investigate their genetic relations. Polymorphism at SSR loci was evaluated on the basis of number of alleles (mean: 9.4), expected heterozygosity (mean: 0.78), and power of discrimination (mean: 0.91). Several synonyms reported in the literature were confirmed, and new cases of synonymy were identified. The parentage of North American cultivars 'Butler', 'Ennis', and 'Royal', the French selection 'Fercoril-Corabel', and 'Impératrice Eugenie' was investigated on the basis of the alleles present at 16 loci and analysis at 8 additional loci. A dendrogram generated from cluster analysis using the unweighted pair group method with arithmetic mean grouped cultivars according to their pedigrees or geographical origins. There was an evident differentiation of the northern European cultivars from the southern European ones and from the Turkish cultivars. The latter clustered close to but separate from the Italian and Spanish clusters. It is very likely that exchanges of cultivars occurred between the central and western Mediterranean basin as a result of human migration and trade. A database containing the SSR profiles of the most important hazelnut cultivars will be useful for identification of cultivars and synonyms, legal protection, and parentage analysis.
    Genome 07/2006; 49(6):598-611. · 1.67 Impact Factor
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    V Scariot, A Akkak, R Botta
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    ABSTRACT: Six polymorphic sequence-tagged microsatellite sites (STMSs) were used to characterize 65 accessions of old garden roses [OGRs (Rosa L. spp.)] from seven botanical sections and 13 horticultural groups. Aims of the study were to define the genetic profiles of accessions and to provide information useful for the classification and pedigree reconstruction of OGRs. In roses, a precise botanical classification is difficult due to repeated hybridization carried out in breeding; OGRs are classified in horticultural groups on the basis of their original parentage or of their morphological traits. A total of 82 alleles were detected at six loci. The number of alleles per locus ranged from six to 21, with an average of 13.7 alleles per locus. A dendrogram was constructed by cluster analysis, displaying the relative genetic similarities between species' accessions, hybrids, and cultivars. Cluster analysis grouped the genotypes into seven major clusters that were substantially consistent with their classification into botanical sections and horticultural groups. Several hypotheses of apportionment of accessions to horticultural groups were evaluated on the basis of the relative position in the dendrogram of the analyzed individuals. Results demonstrated that DNA analyses can contribute to drawing the botanic classification of rose accessions, improving the genetic knowledge on the background of modern rose, and providing the basis for breeding programs.
    Journal of the American Society for Horticultural Science. American Society for Horticultural Science 01/2006; 131(1):66-73. · 1.12 Impact Factor
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    ABSTRACT: In this work, 18 microsatellite loci were developed in the European hazelnut (Corylus avellana L.) using three enriched genomic libraries. They were evaluated on a set of 20 accessions of this species on the basis of number of alleles (mean: 7.1), expected heterozygosity (mean: 0.67), power of discrimination (mean: 0.77) and polymorphism information content (mean: 0.64). Cross-species transferability was evaluated using seven other Corylus species. All primer pairs amplified in all species, except for CaT-C505 in Corylus ferox and CaT-A114 in Corylus californica.
    Molecular Ecology Notes 11/2005; 5(4):934 - 937. · 2.38 Impact Factor
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    ABSTRACT: The general objective of the CASCADE project was to develop a strategy for long-term gene conservation and management of European Chestnut. The distribution area of chestnut was described by climate and edaphic conditions. Eighty-two populations, naturalised – coppice – fruit orchards, were analysed with respect to genetic markers to describe diversity and gene flow. Six naturalised populations from a broad span of climate conditions were included in studies of early growth, drought tolerance, and tolerance against Phytophthora cambivora. Six field trials were established. To identify the socio-economic impact of commodities from chestnut forests and orchards enquiries were distributed to regions, in which chestnut plays a role in the local economy. It was noted that chestnut is demanding with respect to edaphic conditions. A xerothermic index considering precipitation and mean temperature during the growth period was developed. European chestnut stands retain a fairly large amount of marker-based genetic variation. The effective number of alleles is fairly abundant in southern European regions, decreasing toward north and west. Mating probability dropped below 0.01 for distances larger than 2 km, and increased up to about 10% for distances closer than 300 meters according to the gene flow study. Genetic variability among and within populations was observed for juvenile growth, phenology, carbon isotope discrimination, and Phythophthora cambivora susceptibility. The latter variability was lower between domestication levels than within populations. Based on an inventory a distribution map for different Phytophthora species was provided. The enquiries disclosed that restoration of high forests was a top-ranked preference and so was the willingness to pay. Based on the data collected conservation values were derived for adaptive traits and markers. One suggestion for gene conservation was developed in the form of a network of gene resource populations covering the different climatic conditions of the sweet chestnut distribution area.
    Acta horticulturae 01/2005; 693.
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    ABSTRACT: Summary Algeria represents a great resource of almost unknown genetic diversity for all the Mediterranean species, in particular for grapevine (Vitis vinifera L). Often, different local names were given to plant material that resulted identical from the genetic point of view. In this work 12 SSR markers were used to study the relationships and the genetic diversity among 60 autochtonous and cultivated grape varieties coming from the Mediterranean Basin.
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    ABSTRACT: Simple sequence repeat (SSR) markers from Quercus and Castanea were used for comparative mapping between Quercus robur (L.) and Castanea sativa (Mill.). We tested the transferability of SSRs developed in Quercus to Castanea and vice-versa. In total, 47% (25) of the Quercus SSRs and 63% (19) of the Castanea SSRs showed a strong amplification product in the non-source species. From these 44 putative comparative anchor tags, 19 (15 from Quercus and 4 from Castanea) were integrated in two previously established genetic linkage maps for the two genera. SSR loci were sequenced to confirm the orthology of the markers. The combined information from both genetic mapping and sequence analysis were used to determine the homeology between seven linkage groups, aligned on the basis of pairs or triplets of common markers, while two additional groups were matched using a single microsatellite marker. Orthologous loci identified between Q. robur and C. sativa will be useful as anchor loci for comparative mapping studies within the Fagaceae family.
    Theoretical and Applied Genetics 03/2004; 108(3):558-66. · 3.66 Impact Factor
  • Convegno Internazionale sul Vitigno Nebbiolo, Sondrio, Valtellina, Italy, 23-25 June 2004; 01/2004
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    ABSTRACT: Thirty-three simple sequence repeat (SSR) markers were isolated andcharacterized in Castanea sativa (Mill.) from the cultivarGarrone Nero. For the identification of SSR loci, primers were designed on eachside flanking the repeat region and they were initially tested on 5 chestnutsamples using chemiluminescence detection. Twenty four loci where shown to bepolymorphic and the number of alleles detected per locus varied from 2 to 7.Fourteen loci were chosen for the analysis of 20 cultivars grown in North Italyusing the semi-automatic system ABI PRISM 377. These 14 markers showed a highlevel of genetic polymorphism with a total of 90 alleles; the number of allelesranged from 4 to 10 per locus, with an average level of 6.4. The mean expectedand observed heterozygosity were 0.724 (range: 0.649–0.835) and 0.793(range: 0.350–0.950) respectively. The estimated frequency of nullallelesshowed a positive value for 3 loci, but except for 1 locus, the values wereverylow. The total value for the probability of identity was 7.04 10–11. Paternity exclusion probability was very high (0.999),sufficiently high to study pollen flow.
    Molecular Breeding 01/2003; 11(2):127-136. · 3.25 Impact Factor
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    ABSTRACT: Setting up a system for the genetic certification of chestnut cultivars requires the development of a reliable and inexpensive method of DNA typing. Microsatellite (= Simple Sequence Repeats) markers are considered particularly suitable for parentage studies and effective for the cultivar fingerprinting of tree species. The aim of the present work was to obtain a multiplex analysis of chestnut SSR loci by amplifying and electrophoretically separating several loci mixed together, using a semi-automated DNA sequencer and fluorochrome technology for the primer labeling. Initial results indicate the effectiveness of microsatellite analysis for DNA-typing of chestnut cultivars, and multiplex techniques can be used to reduce the cost of the work. Five SSR loci were characterized for size range and number of alleles in 96 individuals. In total 68 alleles were ident -ified. These SSR loci are currently being used in multiplex analyses for the study of gene-flow between chestnut stands. 1 Introduction Castanea sativa Mill., the European chestnut, is wide spread in all the countries along the Mediterranean basin. Its forests extend from the Caucasus through Turkey, Greece, the Balkans to Italy, France, Spain, Portugal and South England. The chestnut declined in Europe during the twentieth century due to the spread of fungal diseases (Phytophthora spp. and Cryphonectria parasitica) and to social-economic changes, such as the depopulation of mountains areas and changes in food habits. In recent times, however, there has been a renewed demand for the nuts and for the wood (BOUNOUS et al. 2000), so that there is now more interest in the cultivation of this species both as a horticul-tural crop and as a forest tree. The demand for selected varieties of chestnut has increased. Thus methods for the reliable characterization and identification of the cultivars have become necessary. The identification of chestnut cultivars has been traditionally based on the observation of morphological characters whose expression is largely influenced by developmental and environmental factors. The setting up of a DNA typing system for cultivar characterization (MULCAHY BERGAMINI et al. 1996, BOTTA et al. 1999) would therefore be very useful. It should have several objectives, including: – to study the existing germplasm and evaluate its genetic variability; – to detect errors in accession names and discover cases of homonymy and synonymy; – to improve the quality of planted material by certifying cultivar true-to-typeness; – to protect breeders' rights; – to exploit local productions (traceability of origin). An efficient genetic identification system should: – use a reliable and standardized technique based on suitable molecular markers; – be affordable; – meet with international acceptance.
    For. Snow Landsc. Res. 01/2001; 76(3):425-428.
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    A. Akkak, V. Scariot, R. Botta
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    ABSTRACT: Summary Simple Sequence Repeats were isolated from a genomic library of Phoenix dactylifera L. All primer pairs produced an amplification product of the expected size and detected high polymorphism among the analysed samples. SSR genetic markers are expected to be a very effective tool for evaluating genetic diversity in date palm germplasm. Cross-transferability in different species and genera was evaluated.