BackgroundThe Mediterranean olive tree (Olea europaea subsp. europaea) was one of the first trees to be domesticated and is currently of major agricultural importance in the Mediterranean region as the source of olive oil. The molecular bases underlying the phenotypic differences among domesticated cultivars, or between domesticated olive trees and their wild relatives, remain poorly understood. Both wild and cultivated olive trees have 46 chromosomes (2n).FindingsA total of 543 Gb of raw DNA sequence from whole genome shotgun sequencing, and a fosmid library containing 155,000 clones from a 1,000+ year-old olive tree (cv. Farga) were generated by Illumina sequencing using different combinations of mate-pair and pair-end libraries. Assembly gave a final genome with a scaffold N50 of 443 kb, and a total length of 1.31 Gb, which represents 95 % of the estimated genome length (1.38 Gb). In addition, the associated fungus Aureobasidiumpullulans was partially sequenced. Genome annotation, assisted by RNA sequencing from leaf, root, and fruit tissues at various stages, resulted in 56,349 unique protein coding genes, suggesting recent genomic expansion. Genome completeness, as estimated using the CEGMA pipeline, reached 98.79 %.ConclusionsThe assembled draft genome of O. europaea will provide a valuable resource for the study of the evolution and domestication processes of this important tree, and allow determination of the genetic bases of key phenotypic traits. Moreover, it will enhance breeding programs and the formation of new varieties.

The origin and transport of the IAA responsible for rooting was studied in carnation (Dianthus caryophyllus L.) cuttings obtained from secondary shoots of the mother plants. The presence of mature leaves in the cuttings was essential for rooting. Removal of the apex and/or the youngest leaves did not reduce the rooting percentage as long as mature leaves remained attached. Removal of mature leaves inhibited rooting for a 24-day period during which the basal leaves grew and reached maturity. After this period rooting progressed as in intact cuttings. Auxin (NAA + IBA) applied to the stem base of defoliated cuttings was about 60% as effective as mature leaves in stimulating rooting. Application of NPA to the basal internode resulted in full inhibition of rooting. The view, deduced from these results, that auxin from mature leaves is the main factor controlling the rooting process was reinforced by the fact that mature leaves contained IAA and exported labelled IAA to the stem. The distribution of radioactivity after application of (5-3H)-IAA to mature leaves showed that auxin movement in the stem was basipetal and sensitive to NPA inhibition. The features of this transport were studied by applying 3H-IAA to the apical cut surface of stem sections excised from cuttings. The intensity of the transport was lower in the oldest node than in the basal internode, probably due to the presence of vascular traces of leaves. Irrespective of the localization of the sections and the carnation cultivar used, basipetal IAA transport was severely reduced when the temperature was lowered from 25 to 4 degrees C. The polar nature of the IAA transport in the sections was confirmed by the inhibition produced by NPA. Local application of IAA to different tissues of the sections revealed that polar auxin transport was associated with the vascular cylinder, the transport in the pith and cortex being low and apolar. The present results strongly support the conclusion that IAA originating from the leaves and transported in the stem through the polar auxin transport pathway was decisive in controlling adventitious rooting.

Aim The biogeographical congruence hypothesis, that similar spatiotemporal patterns of geographical distribution exist across lineages, is revisited in this study, and biogeographical processes in presumed Madrean-Tethyan plants are investigated by employing phylogenetic analyses.Location Mediterranean and Californian floristic regions.Methods The snapdragons (tribe Antirrhineae, Plantaginaceae) are one of the plant groups that best illustrate disjunctions between the New World (14 genera) and the Old World (15 genera). A time-calibrated phylogeny (ndhF sequences) and ancestral-area reconstructions were used to test the hypothesis of biogeographical congruence. We estimated support for sister-group relationships together with the probability of temporal congruence of snapdragons and five additional angiosperm groups using a biogeographical approach based on Bayesian inference, parsimony and maximum-likelihood methods.Results Synchronous divergences of four phylogenetically independent Mediterranean/Californian lineages within Antirrhineae were inferred for the Miocene. This result constitutes the first example of high biogeographical congruence within the same plant group. Analyses of five additional angiosperm groups previously considered exemplars of Madrean-Tethyan disjunctions revealed a total of 10 Mediterranean/Californian sister-group lineages, mostly with Miocene divergence times. In particular, our contrasting biogeographical analysis favoured a prevalent colonization process post-dating the separation of America and Eurasia (Eocene) for at least eight angiosperm lineages.Main conclusions Explicit testing of the Madrean-Tethyan hypothesis did not support predominant vicariance for Mediterranean/Californian sister groups as previously proposed. Instead, eight Mediterranean/Californian sister-group lineages displayed a Miocene divergence, including considerable biogeographical congruence within Antirrhineae (four independent lineages) and Cistaceae (two lineages).

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