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Maria G. Emmanouilidou, Marios C. Kyriacou, and Isabel Trujillo

Implementation of the recently developed Cyprus National Register of Commercial Varieties mandates proper cataloguing of the material conserved in the ex situ Olive Collection at the Agricultural Research Institute of Cyprus. A total of 125 trees belonging to 32 accessions were analyzed using 11 morphological endocarp traits and 14 microsatellite [simple sequence repeat (SSR)] markers. The SSR variability allowed segregation of 16 genotypes among accessions, which were clustered into three main groups based on genetic similarity. Similarity indexes among groups ranged from 0.63 to 0.65 and within groups were ≥0.9. Lower morphological variability was detected among accessions, which conformed to three morphological profiles; moreover, the three morphological profiles corresponded to the three groups of genetic similarity obtained by SSR markers. The identification, based on the unique combination of SSR genotypes and endocarp morphologies, revealed the presence of three cultivars and 15 molecular variants that presented limited molecular differences but morphological profiles identical to their catalogued cultivars. Two cultivars, ‘Ladoelia’ and ‘Kato Drys’, demonstrated molecular variation. The current study underpins the efficient management of olive germplasm collections based on combined molecular and phenotypic characterization of their accessions. The complete cataloguing of olive germplasm ensures the correct distribution of identified and authenticated material across national or international institutions.

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Marios C. Kyriacou, David J. Hannapel, and Richard J. Gladon

Tomato fruit ripening is characterized by a decrease in chlorophyll content and an increase in lycopene synthesis. 5-Aminolevulinic acid (ALA) dehydratase (ALAD) is the fruit committed enzyme in the chlorophyll and heme biosynthetic pathways, and it catalyzes the dimerization of two ALA molecules into porphobilinogen We have focused our attention on the potential pivotal role of ALAD in the developmental regulation of chlorophyll biosynthesis during tomato fruit growth, development, and ripening. We have standardized an assay procedure for measuring the enzymatic activity of ALAD in tomato fruit tissues. The activity of ALAD was assayed from ten days past anthesis to day 60, when fruits where void of chlorophyll. We observed a several-fold decline in ALAD activity to residual levels during fruit ontogeny. Our data also show greater ALAD activity in chlorophyllous organs (leaves, stems, immature fruits) than in nonchlorophyllous organs (roots, ripe fruits), where heme production is predominant.

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Marios C. Kyriacou, Gary F. Polking, David J. Hannapel, and Richard J. Gladon

Activity of 5-aminolevulinic acid (ALA) dehydratase [ALAD, (EC 4.2.1.24)] and soluble protein content were determined in `Rutgers' tomato (Lycopersicon esculentum Mill.) fruit pericarp extracts during development and ripening. ALAD activity in several organs of tomato plant also was determined. Fruit tissue was analyzed at 5-day intervals between days 10 and 60 postanthesis. ALAD activity in fruit tissue declined over time, with the most pronounced decrease occurring between days 10 and 25. At the mature green stage (day 40), and before the breaker stage (day 45), activity of ALAD had declined to a steady-state minimum, and it remained detectable at residual levels throughout ripening (days 40 to 60). Soluble protein content declined less rapidly than did ALAD activity. Immunoblot analysis showed that ALAD protein existed as a doublet of isozymes. One isozyme decreased in abundance, whereas the other isozyme remained constant during development and ripening. ALAD activity was greatest in extracts of chlorophyllous organs (stems, leaves, immature fruit) but only marginally detectable in extracts of nonchlorophyllous organs (roots, overripe fruit). The pH optimum and Km for tomato fruit ALAD were similar to those of ALAD isolated from other sources. Abbreviations: ALA, 5-aminolevulinic acid; ALAD, ALA dehydratase; PBG, porphobilinogen; SDS-PAGE, sodium dodecyl sulfate-polyacry - lamide gel electrophoresis.