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Abstract Background Priming plants with natural products is extensively studied in the agricultural field to reduce the use of synthetic and copper-based pesticides. Previous studies have shown that Oregano essential oil vapour (OEOV) is an effective priming agent against downy mildew (DM) in grapevine (Vitis vinifera L. cv. Chasselas), activating different transcriptomic regulated defence mechanisms. Results In the present study, we complement transcriptomic data with metabolomic insights, confirming some previous regulating patterns and highlighting new mechanisms underlying OEOV-induced resistance. A significant modulation of the phenylpropanoid pathway was noted. The data also confirmed the induction of an oxidative stress response indicated by an up-regulation of reactive oxygen species (ROS)-related genes and a congruent depletion of putative L-glutathione. Interestingly, OEOV promoted the accumulation of organic metabolites such as terpenes and other potential phytoalexins, which could potentially contribute to grapevine innate immune response to Plasmopara viticola. Conclusion Overall, this study uncovered a diverse influence of OEOV on V. vinifera defence mechanisms against DM, enhancing our comprehension of the mode of action of essential oils. This insight offers various prospects for crafting innovative biocontrol products, fostering a more dynamic and sustainable approach to agriculture.

Chilling requirement (CR) for bud dormancy completion determines the time of bud break in apple (Malus × domestica Borkh.). The molecular control of bud dormancy is highly heritable, suggesting a strong genetic control of the trait. An available Infinium II SNP platform for genotyping containing 8,788 single nucleotide polymorphic markers was employed, and linkage maps were constructed in a F1 cross from the low CR M13/91 and the moderate CR cv. Fred Hough. These maps were used to identify quantitative trait loci (QTL) for bud break date as a trait related to dormancy release. A major QTL for bud break was detected at the beginning of linkage group 9 (LG9). This QTL remained stable during seven seasons in two different growing sites. To increase mapping efficiency in detecting contributing genes underlying this QTL, 182 additional SNP markers located at the locus for bud break were used. Combining linkage mapping and structural characterization of the region, the high proportion of the phenotypic variance in the trait explained by the QTL is related to the coincident positioning of Arabidopsis orthologs for ICE1, FLC, and PRE1 protein-coding genes. The proximity of these genes from the most explanatory markers of this QTL for bud break suggests potential genetic additive effects, reinforcing the hypothesis of inter-dependent mechanisms controlling dormancy induction and release in apple trees.

Transcriptional regulation, a multiple-step process, is still poorly understood in the important pig pathogen Mycoplasma hyopneumoniae. Basic motifs like promoters and terminators have already been described, but no other cis-regulatory elements have been found. DNA repeat sequences have been shown to be an interesting potential source of cis-regulatory elements. In this work, a genome-wide search for tandem and palindromic repetitive elements was performed in the intergenic regions of all coding sequences from M. hyopneumoniae strain 7448. Computational analysis demonstrated the presence of 144 tandem repeats and 1,171 palindromic elements. The DNA repeat sequences were distributed within the 5' upstream regions of 86% of transcriptional units of M. hyopneumoniae strain 7448. Comparative analysis between distinct repetitive sequences found in related mycoplasma genomes demonstrated different percentages of conservation among pathogenic and nonpathogenic strains. qPCR assays revealed differential expression among genes showing variable numbers of repetitive elements. In addition, repeats found in 206 genes already described to be differentially regulated under different culture conditions of M. hyopneumoniae strain 232 showed almost 80% conservation in relation to M. hyopneumoniae strain 7448 repeats. Altogether, these findings suggest a potential regulatory role of tandem and palindromic DNA repeats in the M. hyopneumoniae transcriptional profile.