Combat phytopathogenic bacteria employing Argirium-SUNCs: limits and perspectives.

Bacterial plant diseases are difficult to control as the durability of deployed control measures is thwarted by continuous and rapid changing of bacterial populations. Although application of copper compounds to plants is the most widespread and inexpensive control measure, it is often partially efficacious for the frequent appearance of copper-resistant bacterial strains and it is raising concerns for the harmful effects of copper on environment and human health. Consequently, European Community included copper compounds in the list of substances candidates for substitution.

Dodine an effective alternative to copper for controlling , the causal agent of pea-cock eye disease, in highly infected olive trees.

A trial was carried out in central Italy in an olive orchard of cultivar Moraiolo, highly infected by . The aim of the investigation was to evaluate the effects of autumn and spring applications of copper oxychloride or dodine to control the disease. Non treated trees were used as the control.

No- or Low-Content Copper Compounds for Controlling , the Causal Agent of Olive Leaf Spot Disease.

The efficacy of using a synthetic (azoxystrobin + difenoconazole), copper-based (copper oxychloride) and low-content copper compound (copper complexed with gluconate and lignosulphonate) fungicides for controlling , the causal agent of olive spot disease, was evaluated in an olive (cv. Nabali) orchard located in the Kafr Qud area (Palestine) in 2017-2018. Treatments were applied at three different times (February, April, and August).

Race-specific genotypes of pv. tomato are defined by the presence of mobile DNA elements within the genome.

pv. tomato is the causal agent of bacterial speck of tomato, an important disease that results in severe crop production losses worldwide. Currently, two races within phylogroup 01a (PG01a) are described for this pathogen.

Silver nanoclusters with Ag oxidative states are a new highly effective tool against phytopathogenic bacteria.

The main measure worldwide adopted to manage plant bacterial diseases is based on the application of copper compounds, which are often partially efficacious for the frequent appearance of copper-resistant bacterial strains and have raised concerns for their toxicity to the environment and humans. Therefore, there is an increasing need to develop new environmentally friendly, efficient, and reliable strategies for controlling plant bacterial diseases, and among them, the use of nanoparticles seems promising. The present study aimed to evaluate the feasibility of protecting plants against attacks of gram-negative and gram-positive phytopathogenic bacteria by using electrochemically synthesized silver ultra nanoclusters (ARGIRIUM‑SUNCs) with an average size of 1.

Olive leaf spot caused by : An updated review.

Olive leaf spot (OLS) caused by is widespread in all olive-growing areas and continents, where can cause severe yield losses. The disease is often underestimated for the difficulty to reveal early leaf symptoms and for the pathogen-induced phylloptosis, which creates the illusion of healthy and restored plants. The present review provide updated information on taxonomy, pathogen life style and cycle, epidemiology, diagnosis, and control.

Comparative genomics to examine the endophytic potential of Pantoea agglomerans DAPP-PG 734.

Pantoea agglomerans DAPP-PG 734 was isolated as endophyte from knots (tumors) caused by Pseudomonas savastanoi pv. savastanoi DAPP-PG 722 in olive trees. To understand the plant pathogen-endophyte interaction on a genomic level, the whole genome of P.

Synergistic interaction between the type III secretion system of the endophytic bacterium Pantoea agglomerans DAPP-PG 734 and the virulence of the causal agent of olive knot Pseudomonas savastanoi pv. savastanoi DAPP-PG 722.

The endophytic bacterium Pantoea agglomerans DAPP-PG 734 was previously isolated from olive knots caused by infection with Pseudomonas savastanoi pv. savastanoi DAPP-PG 722. Whole-genome analysis of this P.

A Spectrofluorophotometrical Method Based on Fura-2-AM Probe to Determine Cytosolic Ca Level in Complex Bacterial Cells.

Calcium signaling is an emerging mechanism by which bacteria respond to environmental cues. To measure the intracellular free-calcium concentration in bacterial cells, [Ca], a simple spectrofluorometric method based on the chemical probe Fura 2-acetoxy methyl ester (Fura 2-AM) is here presented using Pseudomonad bacterial cells. This is an alternative and quantitative method that can be completed in a short period of time with low costs, and it does not require the induction of heterologously expressed protein-based probes like Aequorin.

A Na /Ca exchanger of the olive pathogen Pseudomonas savastanoi pv. savastanoi is critical for its virulence.

In a number of compatible plant-bacterium interactions, a rise in apoplastic Ca levels is observed, suggesting that Ca represents an important environmental clue, as reported for bacteria infecting mammalians. We demonstrate that Ca entry in Pseudomonas savastanoi pv. savastanoi (Psav) strain DAPP-PG 722 is mediated by a Na /Ca exchanger critical for virulence.

Molecular detection of field predation among larvae of two ladybird beetles is partially predicted from laboratory experiments.

Despite the fact that natural enemies can synergistically contribute to herbivore pest suppression, sometimes predators engage in intraguild predation (IGP) that might dampen trophic cascades. DNA-based gut-content analysis has become common in assessing trophic connections and biocontrol potential by predators in field systems. Here, we developed a molecular technique that can be used to unravel predation among two ladybirds, Coccinella septempunctata and Hippodamia variegata, and their shared prey, Aphis gossypii.

Peach leaf curl disease shifts sugar metabolism in severely infected leaves from source to sink.

Peach leaf curl is a disease that affects the leaves of peach trees, and in severe cases all of the leaf can be similarly affected. This study investigated some effects of this disease on the metabolism of peach leaves in which all parts of the leaf were infected. These diseased leaves contained very little chlorophyll and performed little or no photosynthesis.

Draft Genome Sequence of Erwinia oleae, a Bacterium Associated with Olive Knots Caused by Pseudomonas savastanoi pv. savastanoi.

Erwinia oleae is a nonpathogenic bacterial species isolated from olive knots caused by Pseudomonas savastanoi pv. savastanoi. Since the presence of E.

Draft Genome Sequence of Pseudomonas savastanoi pv. savastanoi Strain DAPP-PG 722, Isolated in Italy from an Olive Plant Affected by Knot Disease.

Olive knot disease, caused by the bacterium Pseudomonas savastanoi pv. savastanoi, seriously affects olive trees in the Mediterranean basin. Here, we report the draft genome sequence of P.

Draft Genome Sequence of a Hypersensitive Reaction-Inducing Pantoea agglomerans Strain Isolated from Olive Knots Caused by Pseudomonas savastanoi pv. savastanoi.

Pantoea agglomerans strains inducing a hypersensitive reaction in tobacco leaves are frequently isolated inside olive knots caused by Pseudomonas savastanoi pv. savastanoi. Here, we report the draft genome sequence of the Italian P.

Bacterial multispecies studies and microbiome analysis of a plant disease.

Although the great majority of bacteria found in nature live in multispecies communities, microbiological studies have focused historically on single species or competition and antagonism experiments between different species. Future directions need to focus much more on microbial communities in order to better understand what is happening in the wild. We are using olive knot disease as a model to study the role and interaction of multispecies bacterial communities in disease establishment/development.

Draft Genome Sequence of Erwinia toletana, a Bacterium Associated with Olive Knots Caused by Pseudomonas savastanoi pv. Savastanoi.

Erwinia toletana was first reported in 2004 as a bacterial species isolated from olive knots caused by the plant bacterium Pseudomonas savastanoi pv. savastanoi. Recent studies have shown that the presence of this bacterium in the olive knot environment increases the virulence of the disease, indicating possible interspecies interactions with P.

Calendula officinalis: A New Natural Host of Pseudomonas viridiflava in Italy.

In November 2010, small necrotic spots surrounded by chlorotic halos, which sometimes enlarged and coalesced to form large dead areas, were observed on leaves of marigold (Calendula officinalis L.) plants grown in the Medieval Garden at the Agricultural Faculty of Perugia (central Italy). Cream-colored bacterial colonies were consistently isolated on nutrient agar (NA) from the diseased leaf tissues.

The Arabidopsis thaliana cysteine-rich receptor-like kinase CRK20 modulates host responses to Pseudomonas syringae pv. tomato DC3000 infection.

In plants, the cysteine-rich repeat kinases (CRKs) are a sub-family of receptor-like protein kinases that contain the DUF26 motif in their extracellular domains. It has been shown that in Arabidopsis thaliana, CRK20 is transcriptionally induced by pathogens, salicylic acid and ozone (O(3)). However, its role in responses to biotic and abiotic stress remains to be elucidated.

Sharing of quorum-sensing signals and role of interspecies communities in a bacterial plant disease.

Pathogenic bacteria interact not only with the host organism but most probably also with the resident microbial flora. In the knot disease of the olive tree (Olea europaea), the causative agent is the bacterium Pseudomonas savastanoi pv. savastanoi (Psv).

Erwinia oleae sp. nov., isolated from olive knots caused by Pseudomonas savastanoi pv. savastanoi.

Three endophytic bacterial isolates were obtained in Italy from olive knots caused by Pseudomonas savastanoi pv. savastanoi. Phenotypic tests in combination with 16S rRNA gene sequence analysis indicated a phylogenetic position for these isolates in the genera Erwinia or Pantoea, and revealed two other strains with highly similar 16S rRNA gene sequences (>99 %), CECT 5262 and CECT 5264, obtained in Spain from olive knots.

PCR-based assay for the detection of Xanthomonas euvesicatoria causing pepper and tomato bacterial spot.

Aims: To develop a PCR-based assay for Xanthomonas euvesicatoria detection in culture and in planta.

Methods And Results: A fragment of 1600 bp specific for X. euvesicatoria was found by repetitive extragenic palindromic sequence-PCR.