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The genotyping of cultivated varieties using molecular markers is a crucial aim of modern plant breeding programmes, germplasm collection management and product traceability. Methods for DNA extraction from olive oil are now available, and the DNA extracted is suitable for PCR applications. The aim of this work was to identify simple and reliable PCR markers useful for cultivar identification and oil traceability. We chose to analyse 13 cultivars and one feral accession of Olea europaea for polymorphism in the intergenic spacer of chloroplast DNA (cpDNA). The spacer analysed in this work showed a pattern of variation that was sufficient to discriminate four out of the 13 cultivars analysed. We propose an identification protocol for these cultivars based on the amplification and subsequent sequencing of the chloroplast trnT-trnD intergenic spacer. The ability to design primers pairs capable of amplifying very small fragments makes these markers useful in traceability protocols, even where the quality, yield and size of the DNA recovered from the oil may be very low. [ABSTRACT FROM AUTHOR]

With the aim of understanding better the distribution and evolution of Agrobacterium rhizogenes genes transferred in the genus Nicotiana, 42 species were screened for presence of rolB, rolC, ORF13, and ORF14. The transferred sequences were then compared within the genus and with current bacterial sequences. The results obtained showed the presence of at least one bacterial gene in 15 species belonging to different subgenera. Sequence analyses supported the hypothesis of coevolution of bacterial and plant sequences, thus suggesting a possible role for the transferred genes in the early events of Nicotiana species differentiation. The high level of conservation of Agrobacterium sequences and the dependence of their expression from the plant physiological context along with previous data suggesting their involvement in the determination of the plant hormonal balance were all consistent with this hypothesis. The results are finally discussed also as to their relevance for the hypothesis of mono and multi ancient infection by Agrobacterium., (Copyright 2001 Academic Press.)

An analysis of the evolution of the genus Nicotiana was carried out with physiological and molecular tools. The capacity of explants from seedlings of several species of Nicotiana to differentiate roots or shoots or to habituate was used to ascertain whether the in vitro behavior of species has a nonrandom distribution in the genus. The results obtained allowed us to identify two groups of species, one root-forming prone composed of Paniculatae (subgenus Rustica) and the other composed of Alatae, Repandae, and Noctiflorae (subgenus Petunioides), with a major tendency toward the production of shoots. Habituation capacity was characteristic of species randomly distributed throughout the phylogenetic tree. These data suggest fixation throughout the evolution of coadapted gene complexes (hormone-related genes) involved in the control of developmental processes. RAPDs, on the other hand, used as molecular markers for the clustering of related species, seem entirely coherent both with classical morphological and karyological studies and with in vitro physiological methods, supporting an early subdivision of the whole genus into two diverging developmental patterns.