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Dominant mutations in the Arabidopsis ETR1 gene block the ethylene signal transduction pathway. The ETR1 gene has been cloned and sequenced. Using the ETR1 cDNA as a probe, we identified a cDNA homologue (eTAE1) from tomato. eTAE1 contains an open reading frame encoding a polypeptide of 754 amino acid residues. The nucleic acid sequence for the coding sequence in eTAE1 is 74% identical to that for ETR1, and the deduced amino acid sequence is 81% identical and 90% similar. Genomic Southern blot analysis indicates that three or more ETR1 homologues exist in tomato. RNA blots show that eTAE1 mRNA is constitutively expressed in all the tissues examined, and its accumulation in leaf abscission zones was unaffected by ethylene, silver ions (an inhibitor of ethylene action) or auxin.

Amplified fragment length polymorphism (AFLP) analysis was used to assess genetic inter-relationships among olive varieties cultivated in the Eastern Mediterranean Basin. The genotypes sampled included most of the important cultivars from Turkey, Greece and the Middle East and selected genotypes from the Western Mediterranean area. A total of 119 polymorphic markers were generated from five selective primer-pair combinations. The combined data sets generated by just two primer-pairs were adequate to discriminate between all 65 genotypes, while each primer-pair could individually identify up to 64 genotypes. A factorial correspondence analysis (FCA) plot indicated that the cultivars clustered into two relatively modestly defined groups. The first broad group was dominated by cultivars from Turkey but also included genotypes originating from the Middle East (Syria and Lebanon) that collectively formed a tight subcluster. The second group comprised Greek cultivars and those originating from the Western Mediterranean. A significant genetic distance value between Greek and Turkish cultivars was provided by an analysis of molecular variance (AMOVA). There was also evidence of substructure here, with an apparent separation of most Spanish and Italian clones. These findings are in general accordance to previous suggestions of an East-West divergence of olive cultivars, although the dichotomy is less extensive than reported previously and complicated by regional variation within each group.

Abscission, organ separation, is accompanied by cell wall breakdown in separation layer cells. In tomato (Lycopersicon esculentum), ethylene-induced abscission is correlated with an increase in polygalacturonase (PG) and endo-beta-1,4-D-glucanase (cellulase) activity. We have identified a putative, abscission-specific cDNA clone for PG, pTAPG1. The TAPG1 cDNA has 43% identity at the amino acid level with the tomato fruit PG. Genomic blot analysis suggests that the gene for TAPG1 is a member of a small subfamily of PG genes that is distinct from the tomato fruit PG. The TAPG1 cDNA hybridizes to mRNA expressed during the course of ethylene-induced leaf and flower abscission. A high level of PG transcript accumulation coincides with the occurrence of abscission. Auxin, an abscission inhibitor, and silver thiosulfate, an ethylene action inhibitor, suppressed accumulation of mRNA in leaf abscission zones complementary to the TAPG1 cDNA. Expression of TAPG1 transcripts is several-fold higher in flower abscission zones than in leaf abscission zones. The identification of cDNAs that encode abscission-specific PG provide and additional tool to study the regulation of abscission and cell wall dissolution in separation layer cells.

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Bar-HRM analysis is a more accurate, faster and less costly alternative method to authenticate vegetable oils, including olive oil, and to detect mixtures of oils.

Prolyl 4‐hydroxylases (P4H; EC 1.14.11.2) have been studied extensively in various organisms and recently in relation to oxygen deficiency while little is known about their role in response to similar stresses in plants. To this direction, we investigated the expression patterns of Arabidopsis P4Hs under hypoxia, anoxia and mechanical wounding. The 13 Arabidopsis P4Hs are low‐abundance transcripts with differential patterns of expression in response to two hypoxic, 1.5% and 5% O2, anoxic conditions and mechanical wounding. The majority of AtP4Hs showed higher levels of expression in roots compared with shoots under hypoxia and anoxia. Hypoxia of 1.5% O2 induced the expression of six AtP4Hs, while hypoxia of 5% O2 and anoxia induced the expression of three and two AtP4Hs, respectively. Moreover, we identified in silico, 308 Arabidopsis genes among the differentially expressed genes under hypoxia that contain proline hydroxylation motifs. It is likely that the AtP4Hs hydroxylate proline residue(s) of the 308 polypeptides suggest involvement in their post‐translational modification process. This modification might serve as an alternative level of regulation for the function of these polypeptides in the context of hypoxic response. Furthermore, six AtP4Hs were upregulated in response to mechanical wounding, suggesting involvement in this stress response.