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Evolution and perspectives of cultivar identification and traceability from tree to oil and table olives by means of DNA markers
No full textIn recent years, an increasing number of typicality marks has been awarded to high-quality olive oils produced from local cultivars. In this case, quality control requires effective varietal checks of the starting materials. Moreover, accurate cultivar identification is essential in vegetative-propagated plants distributed by nurseries and is a pre-requisite to register new cultivars. Food genomics provides many tools for cultivar identification and traceability from tree to oil and table olives. The results of the application of different classes of DNA markers to olive with the purpose of checking cultivar identity and variability of plant material are extensively discussed in this review, with special regard to repeatability issues and polymorphism degree. The characterization of olive germplasm from all countries of the Mediterranean basin and from less studied geographical areas is described and innovative high-throughput molecular tools to manage reference collections are reviewed. Then the transferability of DNA markers to processed products – virgin olive oils and table olives – is overviewed to point out strengths and weaknesses, with special regard to (i) the influence of processing steps and storage time on the quantity and quality of residual DNA, (ii) recent advances to overcome the bottleneck of DNA extraction from processed products, (iii) factors affecting whole comparability of DNA profiles between fresh plant materials and end-products, (iv) drawbacks in the analysis of multi-cultivar versus single-cultivar end-products and (v) the potential of quantitative polymerase chain reaction (PCR)-based techniques
Host influence on patulin production by Penicillium expansum strains causing blue mould and consequent effect on their aggressiveness
No full textA MOLECULAR SURVEY FOR DETECTING TABLE GRAPE CULTIVARS IN COMMERCIAL MUSTS AND WINES OF APULIA REGION.
No full textMolecular traceability and oxidative and hydrolytic degradation of the lipid fraction of PDO Italian table olives
No full textCHARACTERIZATION OF A VITIS VINIFERA GH3 GENE FAMILY INVOLVED IN THE CONTROL OF HORMONE LEVELS
No full textGrapevines (Vitis vinifera L.) produce non-climacteric fruit that exhibit a double sigmoidal
pattern of growth. Ripening occurs during the second growth phase when grapes change colour,
start to soften, accumulate reducing sugars, metabolise organic acids and synthesise flavour
compounds. All these biochemical and physiological changes affect the quality of the fruit and
therefore of the wine. Although the physiological processes underlying the ripening have been
described the mechanisms that control the ripening of grape berries are not well known. Abscisic
acid, ethylene and brassinosteroids are considered as promoters of ripening, as treatments of
immature berries with these hormones can advance ripening. In grape, auxin levels are high early in
development, then decline towards the onset of ripening (veraison). Indole-3-acetic acid (IAA) is
the most abundant auxin in grape berries. Auxins can delay ripening when applied at an appropriate
time prior to veraison. One important mechanism for controlling the levels of free, biologically
active IAA is its enzymatic conjugation to amino acids. GH3 enzymes, encoding IAA-amido
synthetases, are responsible for this conjugation. Previous phylogenetic analyses of Arabidopsis
thaliana GH3 proteins classified them into three groups based on sequence similarity. Group II
enzymes have been shown to be active on IAA and a member of group I conjugates jasmonic acid
to amino acids.
In order to elucidate the involvement of GH3 genes in grape berry ripening, we studied seven
GH3 genes, six of which are IAA-amido synthetases, the other is a jasmonic acid-amido synthetase.
The primary objective was to determine the subcellular localization of these enzymes. GFP-protein
fusion constructs for all seven enzymes were transiently expressed in capsicum by biolistic
bombardment and the transformed cells were scanned by fluorescence microscopy. All of these
proteins displayed a cytosolic localization, confirming the in silico prediction. In order to further
understand the likely function of these genes their expression patterns were analysed in different
tissues comparing the varieties Shiraz and Cabernet Sauvignon. All of the IAA-amido synthetase
genes showed different patterns of expression suggesting that although they all conjugate IAA to
amino acids there is a degree of specialisation at the organ level
Genetic structure and natural variation associated with host of origin in Penicillium expansum strains causing blue mould.
No full textBlue mould, caused by Penicillium expansum, is one of the most economically damaging postharvest diseases
of pome fruits, although it may affect a wider host range, including sweet cherries and table grapes. Several
reports on the role of mycotoxins in plant pathogenesis have been published, but few focussed on the
influence of mycotoxins on the variation in host preference amongst producing fungi. In the present study
the influence of the host on P. expansum pathogenicity/virulence was investigated, focussing mainly on the
relationship with patulin production. Three P. expansum strain groups, originating from apples, sweet cherries,
and table grapes (7 strains per host) were grown on their hosts of isolation and on artificial media derived
from them. Strains within each P. expansum group proved to be more aggressive and produced more patulin
than the other two groups under evaluation when grown on the host from which they originated. Table grape
strains were the most aggressive (81% disease incidence) and strongest patulin producers (up to 554 μg/g).
The difference in aggressivenessamongst strainswas appreciable only in the presence of a living host, suggesting
that the complex pathogen–host interaction significantly influenced the ability of P. expansum to cause the
disease. Incidence/severity of the disease and patulin production proved to be positively correlated, supporting
the role of patulin as virulence/pathogenicity factor. The existence of genetic variation amongst isolates was
confirmed by the High Resolution Melting method that was set up herein, which permitted discrimination of
P. expansum from other species (P. chrysogenum and P. crustosum) and, within the same species, amongst the
host of origin. Host effect on toxin production appeared to be exerted at a transcriptional level
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