The emergence and spread of Quinone outside Inhibitor (QoI) fungicide resistance in the Irish Zymoseptoria tritici population in the early 2000s had immediate impacts on the efficacy of the entire group of fungicides for the control of septoria tritici blotch. As a result, a dramatic reduction in the quantities applied to winter wheat occurred in the following seasons. Even in the absence of these fungicides, the frequency of the resistance allele, G143A in the pathogens mtDNA has remained exceptionally high (>97%), and as such, it can be anticipated that continued poor efficacy of current QoI fungicides will be observed. Amongst the isolates with G143A, differences in sensitivity to the QoI pyraclostrobin were observed in vitro. The addition of the alternative oxidase (AOX) inhibitor salicylhydroxamic acid increased sensitivity in these isolates, suggesting some continued impairment of respiration by the QoI fungicides, albeit weak. Interestingly, amongst those tested, the strains from a site with a high frequency of inserts in the MFS1 transporter gene known to enhance QoI efflux did not exhibit this increase in sensitivity. A total of 19 mtDNA haplotypes were detected amongst the 2017 strain collection. Phylogenetic analysis confirmed the suggestion of a common ancestry of all the haplotypes, even though three of the haplotypes contained at least one sensitive strain.

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Grapevine (Vitis vinifera L.) is a crop of major economic importance. However, grapevine yield is guaranteed by the massive use of pesticides to counteract pathogen infections. Under temperate-humid climate conditions, downy mildew is a primary threat for viticulture. Downy mildew is caused by the biotrophic oomycete Plasmopara viticola Berl. & de Toni, which can attack grapevine green tissues. In lack of treatments and with favourable weather conditions, downy mildew can devastate up to 75% of grape cultivation in one season and weaken newly born shoots, causing serious economic losses. Nevertheless, the repeated and massive use of some fungicides can lead to environmental pollution, negative impact on non-targeted organisms, development of resistance, residual toxicity and can foster human health concerns. In this manuscript, we provide an innovative approach to obtain specific pathogen protection for plants. By using the yeast two-hybrid approach and the P. viticola cellulose synthase 2 (PvCesA2), as target enzyme, we screened a combinatorial 8 amino acid peptide library with the aim to identify interacting peptides, potentially able to inhibit PvCesa2. Here, we demonstrate that the NoPv1 peptide aptamer prevents P. viticola germ tube formation and grapevine leaf infection without affecting the growth of non-target organisms and without being toxic for human cells. Furthermore, NoPv1 is also able to counteract Phytophthora infestans growth, the causal agent of late blight in potato and tomato, possibly as a consequence of the high amino acid sequence similarity between P. viticola and P. infestans cellulose synthase enzymes.

Protein-protein interactions (PPIs) contribute to regulate many aspects of cell physiology and metabolism. Protein domains involved in PPIs are important building blocks for engineering genetic circuits through synthetic biology. These domains can be obtained from known proteins and rationally engineered to produce orthogonal scaffolds, or computationally designed de novo thanks to recent advances in structural biology and molecular dynamics prediction. Such circuits based on PPIs (or protein circuits) appear of particular interest, as they can directly affect transcriptional outputs, as well as induce behavioral/adaptational changes in cell metabolism, without the need for further protein synthesis. This last example was highlighted in recent works to enable the production of fast-responding circuits which can be exploited for biosensing and diagnostics. Notably, PPIs can also be engineered to develop new drugs able to bind specific intra- and extra-cellular targets. In this review, we summarize recent findings in the field of protein circuit design, with particular focus on the use of peptides as scaffolds to engineer these circuits.

varieties, transgenic or knockout lines able to maintain their green color longer than wild-type plants. In these plants, long-lasting leaf coloration is correlated to durable chlorophyll accumulation compared to wild-type plants or standard varieties, and it is often associated with delayed senescence 52. In Arabidopsis, senescence mechanisms induce the expression of ORESARA1 (ORE1) and ORE1 SISTER1 (ORS1) genes. ORE1 activates program cell death and ORS1 participates to salt-induced senescence; the corresponding knockout mutant plants display a stay-green phenotype and delayed senescence 19,20,22,26. Conversely, the disruption of VND-INTERACTING2 (VNI2) and JUNGBRUNNEN1 (JUB1)-which also encode for two NAC proteins-causes early senescence while their overexpression induces a stay-green phenotype 24,53. Recently, it was demonstrated that transgenic tomato lines, with reduced accumulation of SlNAP2 messenger (Solanum lycopersicum NAC-like, activated by Apetala3/ Pistillata), display a stay-green phenotype even upon ABA (abscisic acid) application 33. In this manuscript, we describe the role of Solyc12g036480, which encodes a NAC transcription factor able to modulate leaf senescence in tomato. We demonstrate that Solyc12g036480 downregulation, achieved via Virusinduced gene silencing (VIGS), confers longer life span and delayed overall senescence in tomato plants; for this reason we named this gene HḖBĒ (HEB) after the Greek youth goddess. Results and discussion HEB expression analyses. The tomato NAC TFs family counts 101 members and only few of them have been functionally characterized. As yet, tomato NAC proteins have been described as involved in defense responses, stomata opening and closure, drought tolerance, flower-boundary morphogenesis, leaf senescence and fruit ripening 33,54-57. Among these 101 NAC members, we have selected Solyc12g036480/HEB for a deeper characterization. According to the transcriptome data collection of the Tomato Genome Consortium, HEB is equally transcribed in leaves and roots, but from the experimental data of Huang and Schiefelbein, HEB messenger is not detected in roots 58,59. In order to define temporally and spatially HEB expression pattern, quantitative Real-Time PCRs (qRT-PCRs) were performed. Expression analyses were carried out using organs dissected by Micro-tom plants; UBIQUITIN 3 (UBI3) and ELONGATION FACTOR 1α (EF1α) were used as reference genes 60. HEB transcript was found in young and old leaves and in young floral buds, but its mRNA is barely detected in roots, stem, mature green and red ripe fruits [developmental stages as described in 61 (Fig. 1)].