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Oomycetes, a large group of fungus-like organisms, include some destructive plant pathogens causing enormous economic damage. Phylogenetically, oomycetes belong to the kingdom Straminipila and have diverse lifestyles, including saprotrophs and both general and specialized pathogens of various eukaryotic supergroups. A rapid increase in genomic studies and next-generation sequencing technologies have led to significant progress in understanding oomycete lifestyles. However, their genetics, including transcriptional regulation, have been studied to a much lesser extent. Here, we provide a cross-species analysis of oomycete promoter for providing a first step towards elucidating gene regulation networks related to pathogenicity and life cycle stages. The clustered DNA sequences of Plasmopara halstedii transcriptome time-series expression level dataset from a preliminary study have been used as a core reference for cross-species comparisons. Using a computational pipeline, 46 potential transcription factor binding site (TFBS) motifs in 25 clusters with functionally conserved downstream genes of downy mildew and two Phytophthora species, regardless of the gene expression levels of Phytophthora transcriptomes, were found. This can now be followed up by knock-out experiments in oomycete species amenable for genetic modification. [ABSTRACT FROM AUTHOR]

Plasmopara viticola is the causal agent of grapevine downy mildew (DM). DM resistant varieties deploy effector-triggered immunity (ETI) to inhibit pathogen growth, which is activated by major resistance loci, the most common of which are Rpv3 and Rpv12. We previously showed that a quick metabolome response lies behind the ETI conferred by Rpv3 TIR-NB-LRR genes. Here we used a grape variety operating Rpv12-mediated ETI, which is conferred by an independent locus containing CC-NB-LRR genes, to investigate the defence response using GC/MS, UPLC, UHPLC and RNA-Seq analyses. Eighty-eight metabolites showed significantly different concentration and 432 genes showed differential expression between inoculated resistant leaves and controls. Most metabolite changes in sugars, fatty acids and phenols were similar in timing and direction to those observed in Rpv3-mediated ETI but some of them were stronger or more persistent. Activators, elicitors and signal transducers for the formation of reactive oxygen species were early observed in samples undergoing Rpv12-mediated ETI and were paralleled and followed by the upregulation of genes belonging to ontology categories associated with salicylic acid signalling, signal transduction, WRKY transcription factors and synthesis of PR-1, PR-2, PR-5 pathogenesis-related proteins. [ABSTRACT FROM AUTHOR]

Geranium phaeum is a popular ornamental plant in Europe. Downy mildew disease caused by Plasmopara was found on this plant once 50 years ago in Poland, but at that time attributed to the native species, Plasmopara pusilla. Here we report the recurrence of downy mildew disease on G. phaeum in Germany. Molecular phylogenetic analysis and morphological investigations revealed that the causal agent of the new outbreak is P. wilsonii, but not P. pusilla. Plasmopara wilsonii had previously been found only in the USA and Korea on various hosts of Geranium. The presence of P. wilsonii on G. phaeum in Europe should be closely monitored, as downy mildew caused by this species probably has the potential to become an important emerging disease on its ornamental host, especially, as also the native G. molle is able to sustain the pathogen. [ABSTRACT FROM AUTHOR]

Resistance of grape downy mildew caused by Plasmopara viticola against different fungicide classes has been reported in Europe. The main objective of the present study was to measure the sensitivity status of P. viticola populations to four fungicide active ingredients used in the Luxembourgian vine-growing region and to investigate the presence of resistant populations. Thus, leaf samples with downy mildew symptoms were collected in 19 vineyards along the river Moselle in 2010 and 2011. Samples were analysed in both years for carboxylic acid amides (CAA) and the quinone outside inhibitors (QoI), using a microplate conidia growth inhibition assay. In 2011, a leaf disc assay was used in addition to determine the sensitivity profile of the sampled populations to phenylamides (PA) and to cymoxanil. Results showed that in average, 64% (2010) or 81% (2011) of the zoospores were resistant to QoI fungicides, and 91% (2010) or 85% (2011) to the CAA fungicide dimethomorph. Furthermore, in 2011, all populations were classified as extremely resistant to the PA fungicide kiralaxyl, indicating that the sampled Luxembourgian populations contained at least 50% of resistant strains. No population was controlled by cymoxanil at the rate of 100 mg/l. In average, 84% of the populations showed a minimum inhibitory concentration (MIC) between 300-800 mg/l, and 16% a MIC reaching 800 mg/l. The presented results indicate that fungicide resistance against CAAs, QoIs, PAs and cymoxanil is currently widespread in the Luxembourgian wine-growing area. [ABSTRACT FROM AUTHOR]

Functionalized polyhedral carboranes, including amino acid analogs, have unique physicochemical properties and are used as experimental anticancer agents. However, our current knowledge on their effect in nonmammalian biological systems is limited. We investigated the activity spectrum in vitro of o-carboranylalanine ( o-Cba), considered to be a highly lipophilic analog of phenylalanine, against representative plant pathogenic bacteria and fungi of various taxonomic position. The antibacterial effect of o-Cba against some species was comparable to that of the widely used agricultural antibiotic, streptomycin. The sensitivity of individual bacterial species to o-Cba within the same genus varied to a greater extent than the average sensitivity of various genera. In general, this carborane-containing amino acid was more toxic to Gram positive bacteria ( Bacillus, Corynebacterium, Curtobacterium, Micrococcus, Rhodococcus, and Staphylococcus) than to Gram negative ones ( Agrobacterium, Erwinia, Escherichia, Pseudomonas, Rhizobium, and Xanthomonas). Compared to the commercial fungicide, prochloraz, o-Cba was weakly toxic against various fungi (Zygo- and Ascomycota). It was also inferior to the commercial fungicide metalaxyl in inhibiting the vegetative growth of oomyceteous plant pathogens ( Pythium irregulare, Phytophthora cryptogea and Plasmopara halstedii). Against the asexual spores of P. halstedii, o-Cba, however, was over a thousandfold more active than tridemorph, a selective zoospore inhibitor fungicide. For all taxonomic groups, the observed antimicrobial effect of o-Cba could be diminished with histidine, but not with phenylalanine. In studies on healthy and mildew-infected sunflower and tobacco plants o-Cba showed neither fungicidal nor phytotoxic effects at 500ppm. This is the first report on the biological activity spectrum of a carborane-containing amino acid. [ABSTRACT FROM AUTHOR]

Three important phytopathogenic spores which cause serious fungal diseases on vines ( Botrytis, Uncinula and Plasmopara) were monitored from June 2, 1994 to September 21, 1994, in vineyards belonging to ‘Estación de Enoloxía e Viticultura’ of Ponte San Clodio-Leiro (Ourense), one of the most important vine growing areas of northwest of Spain. The concentrations for each of the genera were correlated with rainfall, humidity, maximum, minimum and average temperatures. These meteorological parameters are currently used to determine chemical sprays to be applied to the vines. The aim was to establish the behaviour of airborne concentrations of spores of these taxa during the period from the flowering to harvest because these are the periods of greatest susceptibility to attack by these pathogens. [ABSTRACT FROM AUTHOR]

Vale dos Vinhedos appellation of origin has a very recent history as industrial wine making region. In this study we investigated the genetic and phenotypic variability of Saccharomyces cerevisiae strains isolated from South-Brazilian vineyards in order to evaluate strain fermentation aptitude and copper and sulphites tolerance. Merlot grape bunches were collected from three vineyards and yeast isolation was performed after single bunch fermentation. High genotypic variability was found and most of the genotypes revealed to be vine-specific. No industrial strain dissemination was present in the sampled vineyards, although it has been wildly reported in traditional winemaking countries. From the phenotypic traits analysis these Brazilian native strains showed good fermentation performances, good tolerance to sulphites and, in particular, a high copper tolerance level. Copper is the most important metal in the formulation of fungicides against downy mildew (Plasmopara viticola), one of the most harmful disease of the vines, and other fungal pests. The high tolerance to copper suggests an environmental adaptation to the strong use of copper-based fungicides, requested by the wet subtropical climate.Graphical Abstract: [ABSTRACT FROM AUTHOR]

An abstract of the article "First Report owny Mildew (Plasmopara Obducens) on Impatiens Walleriana in Italy " by A. Garibaldi and Colleagues is presented.