Newcastle disease virus (NDV) is one of the most serious contagions affecting domestic poultry and other avian species. It causes high morbidity and mortality, resulting in huge economic losses to the poultry industry worldwide. Despite vaccination, NDV outbreaks increase the need for alternative prevention and control means. In this study, we have screened fractions of Buthus occitanus tunetanus (Bot) scorpion venom and isolated the first scorpion peptide inhibiting the NDV multiplication. It showed a dose dependent effect on NDV growth in vitro, with an IC₅₀ of 0.69 µM, and a low cytotoxicity on cultured Vero cells (CC50 > 55 µM). Furthermore, tests carried out in specific pathogen-free embryonated chicken eggs demonstrated that the isolated peptide has a protective effect on chicken embryos against NDV, and reduced by 73% the virus titer in allantoic fluid. The N-terminal sequence, as well as the number of cysteine residues of the isolated peptide, showed that it belongs to the scorpion venom Chlorotoxin-like peptides family, which led us to designate it “BotCl”. Interestingly, at 10 µg/mL, BotCl showed an inhibiting effect three times higher than its analogue AaCtx, from Androctonus australis (Aa) scorpion venom, on NDV development. Altogether, our results highlight the chlorotoxin-like peptides as a new scorpion venom AMPs family.

Salt stress was applied to tomato commercial genotypes to study adverse effects on their phenotypic traits. Three were saline tolerant (San Miguel, Romelia and Llanero), two were mildly tolerant (Perfect peel HF1 and Heinz 1350) whereas the remaining were sensitive. Genotyping cultivars using 19 polymorphic SSRs out of 25 tested produced a total of 70 alleles with an average of 3.68 alleles per locus and PIC values ranging from 0.22 (SSR 26, 92, 66 and TG35) to 0.82 (SSR 356). Principal component analysis (PCA) showed two contrasting panels discriminating tolerant and sensitive groups and one panel with scattered genotypes. STRUCTURE analysis clustered genotypes within three groups in accordance with their salt stress behavior. The success of tomato salt-tolerance breeding programs can be enhanced through molecular characterization of diversity within commercial cultivars that adapt differently to stress conditions. To this end, we combined phenotypes and SSR marker-genotypes to seek sources of salt tolerance that might be tomato species-specific. We integrated and represented genotype-phenotype associations from multiple loci into a multi-layer network representation. It is a systemic view linking discriminating genotypes to salt stress phenotypes, which may guide strategies for the introgression of valuable traits in target tomato varieties to overcome salinity.

During recent decades, global warming has intensified, altering crop growth, development and survival. To overcome changes in their environment, plants undergo transcriptional reprogramming to activate stress response strategies/pathways. To evaluate the genetic bases of the response to heat stress, Conserved DNA-derived Polymorphism (CDDP) markers were applied across tomato genome of eight cultivars. Despite scattered genotypes, cluster analysis allowed two neighbouring panels to be discriminate. Tomato CDDP-genotypic and visual phenotypic assortment permitted the selection of two contrasting heat-tolerant and heat-sensitive cultivars. Further analysis explored differential expression in transcript levels of genes, encoding heat shock transcription factors (HSFs, HsfA1, HsfA2, HsfB1), members of the heat shock protein (HSP) family (HSP101, HSP17, HSP90) and ascorbate peroxidase (APX) enzymes (APX1, APX2). Based on discriminating CDDP-markers, a protein functional network was built allowing prediction of candidate genes and their regulating miRNA. Expression patterns analysis revealed that miR156d and miR397 were heat-responsive showing a typical inverse relation with the abundance of their target gene transcripts. Heat stress is inducing a set of candidate genes, whose expression seems to be modulated through a complex regulatory network. Integrating genetic resource data is required for identifying valuable tomato genotypes that can be considered in marker-assisted breeding programmes to improve tomato heat tolerance.

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at the post-transcriptional level and play a crucial role in numerous disease processes, including infections. Although intracellular microbial pathogens are known to modulate host cell gene expression to establish permissive conditions for infection, the specific role of host-encoded miRNAs underlying such subversion remains poorly understood. In this study, we employed the protozoan parasite Leishmania amazonensis as a model system to investigate how infection of macrophages modifies the host cell miRNA profile to evade antimicrobial functions and to establish permissive conditions for intracellular proliferation. Dual RNA-seq analyses using matched mRNA and miRNA-enriched samples from uninfected and L. amazonensis -infected bone marrow-derived macrophages (BMDMs) revealed 102 differentially expressed miRNAs (padj<0.05), with 18 miRNAs showing reduced and 84 miRNAs showing increased abundance in infected BMDMs. Mapping putative networks of miRNA-mRNA interactions based on the observed expression changes, combined with Gene Ontology enrichment analyses, allowed us to identify potential miRNA target genes involved in key biological processes and metabolic pathways that permit parasite intracellular survival and proliferation. Our analyses predict the existence of a large miRNA-mRNA network affecting the expression level of numerous transcription factors that indicates inhibition of the NF-κB-dependent inflammatory response or the promotion of cholesterol biosynthesis during infection. In particular, the over 10e3-fold increase in the abundance of mmu-miR-686 in infected BMDMs was correlated with a reduced abundance of putative target transcripts implicated in miRNA biogenesis itself, in RNA binding, and in regulation of apoptosis, such as Caspase 12 , the mRNA decay activator protein Zfp36l1 or Leukemia Inhibitory Factor Receptor Alpha . Likewise, the over 200-fold increase in abundance of mmu-miR-6546-3p was associated with a reduced abundance of putative target mRNAs implicated in cytokine-mediated signaling, positive regulation of apoptotic process and regulation of gene expression, affecting, for example, the MADS box transcription enhancer factor 2 , the transformation related protein 53 inducible nuclear protein 1 , or the G protein-coupled receptor 35 . Interestingly, both miRNAs are predicted to simultaneously target 32 mRNAs that showed reduced abundance in infected BMDMs, including Maturin Neural Progenitor Differentiation Regulator ( Mturn ), a regulator of NF-κB transcription factor activity. In conclusion, our approach provides novel insight into molecular mechanisms that may govern macrophage subversion and intracellular Leishmania survival. Our results shed new light on the complex relationship among miRNAs, macrophage gene expression and Leishmania infection, proposing regulatory feed-forward loops (FFLs) and feedback loops (FBLs) between miRNAs and TFs as a novel target of Leishmania immune subversion. These findings open exciting new avenues for the development of intervention strategies aimed at disrupting such crucial interactions, for example using an anti-miR (antagomir) approach against mmu-miR-686 and mmu-miR-6546-3p.

Pyrenophora teres f. maculata is the causal agent of barley spot form net blotch (SFNB), a major stubble-borne disease in many barley-growing areas worldwide. In plants, the Nucleotide-Binding Site-Leucine-Rich Repeat (NBS-LRR) gene family functions in immunity against a variety of pathogens and pests. From a pre-established set of NBS-type resistance gene candidates, we have selected three candidate genes, HvNBS10, HvNBS72 and HvNBS85, to analyze their possible involvement in P. teres f. maculata resistance. The studied genes were mapped on chromosomes 5H and 7H. Expression profiles using qRT-PCR, 48 hours after infection by P. teres. f. maculata, revealed that the transcription of all genes acted in the same direction (down-regulation) in both resistant and susceptible cultivars, although they showed a variation in transcript dosage. This result suggests that coordinated transcriptional responses of multiple barley NBS genes would be required to an efficient response against P. teres f. maculata. Moreover, the phylogenetic analysis revealed that the studied barley candidate R genes were characterized by a high homology with the barley Nbs2-Rdg2a gene conferring resistance to the fungus Pyrenophora graminea, suggesting a common origin of P. graminea and P. teres resistance genes in barley, following pathogens evolution. The genes characterized in the present study hold potential in elucidating the molecular pathways and developing novel markers associated with SFNB resistance in barley.

Staphylococcus aureus is a pathogen that has developed resistance to each new antibiotic introduced for half a century especially through the acquisition of the mecA gene. This bacterial resistance to antibiotics represents a major public health problem. New revolutions are underway, in particular the design of drugs and vaccines targeting the system for detecting the regulatory quorum of the accessory gene ( agr ). It has been shown that the pathogenicity and resistance of S. aureus can be modulated through the intervention of this system. For this reason, we propose in this present work, a new therapeutic design based on an in silico study to identify plant miRNAs that could target this system as well as the mecA gene based on recent studies showing the inter-realm regulation of human transcripts by plant miRNAs. Out of a total of 20643 miRNAs from mature plants, we identified 29 miRNAs, obtained by the selection criteria MFE ≥ -25 kcal / mol, which could potentially target selected genes of S. aureus . Fifteen of them were selected on the basis of their thermodynamic stability. Interestingly, The seeds of ptc - miR171g and ptc - miR171h ( Populus trichocarpa ) both of which almost similar mature miRNA sequence was found to target UCCC region of RNAIII gene. miRNAs from plants targeting S. aureus have the potential to be developed as an alternative therapy of the future. To our knowledge, it is the first therapeutic alternative of the future via the in silico identification of plant miRNAs targeting pathogenic bacteria. Graphical