phage KΦ1, a member of
family, was isolated from the rhizosphere of pepper plants showing symptoms of bacterial spot. The phage strain expressed antibacterial activity to all
strains tested and did ...not lyse other
spp., nor other less related bacterial species. The genome of KΦ1 is double-stranded DNA of 46.077 bp including 66 open reading frames and an average GC content of 62.9%, representing the first complete genome sequence published for a phage infecting xanthomonads associated with pepper or tomato. The highest genome similarity was observed between phage KΦ1 and the
pv.
specific phage OP2. On the other hand, when compared with other members of the genus
, the genome similarity was lower. Forty-four (67%) predicted KΦ1 proteins shared homology with
phage OP2, while 20 genes (30%) were unique to KΦ1. Phage KΦ1, which is chloroform resistant and stable in different media and in the pH range 5-11, showed a high titer storage ability for at least 2 years at +4°C. Copper-hydroxide and copper-oxychloride reduced phage activity proportionally to the used concentrations and the exposure time. UV light was detrimental to the phage strain, but skim milk plus sucrose formulation extended its survival
. The phages survived for at least 7 days on the surface of pepper leaves in the greenhouse, showing the ability to persist on the plant tissue without the presence of the host bacterium. Results of three repeated experiments showed that foliar applications of the unformulated KΦ1 phage suspension effectively controlled pepper bacterial spot compared to the standard treatment and the untreated control. The integration of the phage KΦ1 and copper-hydroxide treatments resulted in an increased efficacy compared to the copper-hydroxide alone.
Bacterial fruit blotch and seedling blight, caused by
, is one of the most destructive diseases of melon and watermelon in many countries. Pathogen-free seed and cultural practices are major pillars ...of the disease control. However, use of bacteriophages as natural biocontrol agents might also contribute to the disease management. Therefore, we isolated 12 bacteriophages specific to
, from phyllosphere and rhizosphere of diseased watermelon plants. The phage strains were characterized based on their host range, plaque and virion morphology, thermal inactivation point, adsorption rate, one step growth curve, restriction fragment length polymorphism (RFLP), and genomic analysis. Transmission electron microscopy of three phage strains indicated that they belong to the order
, family
All phages lysed 30 out of 32 tested
strains isolated in Serbia, and did not lyse other less related bacterial species. They produced clear plaques, 2 mm in diameter, on bacterial lawns of different
strains after 24 h of incubation. The thermal inactivation point was 66 or 67°C. They were stable at pH 5-9, but were sensitive to chloroform and inactivated in either 5 or 10 min exposure to ultraviolet (UV) light. RFLP analysis using
RI,
I and
HI enzymes did not show genetic differences among the tested phages. Adsorption rate and one step growth curve were determined for the
phage ACF1. Draft genome sequence of the ACF1 phage was 59.377 bp in size, with guanine-cytosine (GC) content 64.5%, including 89 open reading frames. This phage shared a very high genomic identity with
phage ACPWH, isolated in South Korea. Evaluation of systemic nature of ACF1 strain showed that it can be absorbed by roots and translocated to upper parts of watermelon plants where it survived up to 10 days.
Tomatoes encounter many pathogens, such as fungi and bacteria, which reduce the yield and quality of plants and lead to large losses in production. The application of plant protection products (PPPs) ...is still an important and most effective measure to control plant diseases. However, the use of chemicals in agriculture contributes to environmental pollution and biodiversity loss, and it can also threaten non-target living organisms. Biological control is a widely accessible, environmentally safe, and cost-efficient alternative for the prevention and suppression of plant diseases.
species with antimicrobial and plant growth-promoting effects are most frequently used as biocontrol agents to increase the resilience of agricultural production against biotic stresses. The present review discusses the antagonistic mechanisms and the biocontrol potential of
spp. against tomato diseases caused by different pathogens. The main mechanisms of
spp. include the production of antimicrobial compounds (antibiotics, extracellular enzymes, siderophores, and volatile compounds), competition for nutrients and space, and induced systemic resistance (ISR). Although
-based PPPs have been developed and commercialised worldwide for various crops and pathogens, the efficiency issues are still subject to debate. Additionally, a combined strategy for controlling tomato diseases based on
spp. and other available methods (conventional or natural-based) is a promising research field.
Abstract
Fire blight is the most devastating disease affecting pome fruit production globally. The pathogen is native to North America and was imported to western Europe in the 1950s, progressively ...spreading over the continent in the ensuing decades. Previous phylogenetic studies have revealed the extreme genetic homogeneity of the pathogen outside its center of origin, which makes epidemiological studies difficult. These are generally only possible using hypervariable regions of the genome such as those represented by CRISPRs (Clustered Regularly Interspaced Short Palindromic Repeats), which are, however, not practical to sequence due to their size and variability. Here, we present a simple PCR assay targeting the duplication of a single CRISPR spacer in
Erwinia amylovora
that was found to be an important marker to discriminate between two main European populations of the pathogen. We implemented the assay on a total of 582 isolates to follow the spread of fire blight across the continent over several decades and, wherever possible, within single countries. The results obtained point to the occurrence of two major separate introduction events for
E. amylovora
in Europe that occurred approximately 20 years apart, and confirmed the existence of two principal distribution areas located in Northeastern Europe and the Eastern Mediterranean Basin from which the pathogen moved on to colonize the Eurasian continent.
Acidovorax citrulli, the causal agent of bacterial fruit blotch (BFB), is an economically important pathogen of watermelon and related plant species worldwide. In the period 2014–2018, several ...outbreaks of BFB were observed in major watermelon production regions in Serbia. A total of 43 strains, isolated from symptomatic watermelon tissue, were analyzed by biochemical, pathogenic and molecular tests. Based on the phenotypic characteristics, PCR assay, and 16S rRNA gene sequence analysis, all strains were identified as A. citrulli. A multilocus sequence analysis of the four housekeeping (adk, gyrB, pilT and gltA) and three virulence genes (Aave_1548, avrRx01 and luxR) revealed that studied A. citrulli strains represent the homogeneous population and they clustered together with group II reference strain AAC00-1. Strain affiliation to group II was confirmed by PCR based on the putative type III secretion effector gene and by duplex PCR test. High homogeneity of studied strains was also confirmed by BOX-PCR. Differences were observed for two strains in their pathogenicity as well as susceptibility to copper compounds. Moreover, six major watermelon varieties grown in Serbia showed high sensitivity to the pathogen, while cross inoculation assay revealed that the strains were able to infect other species within the Cucurbitaceae family.
The objective of this study was to investigate whether the sensitivity of E. necator populations to several important fungicide groups has changed in Serbia. Field trials, bioassays, and molecular ...tests were conducted from 2019 to 2022. Samples were collected from commercial, experimental and extensive vineyards. Low efficacy of QoIs, azanaphthalenes and aryl-phenyl-ketones was observed in the field trials. A total of 110 isolates were analyzed by qPCR for the presence of the G143A mutation. The mutation was positively detected in 61.8% of the isolates, therefore isolates containing >95% of the G143A allele were QoI-resistant in bioassays. Contrary, QoI-sensitive isolates contained <5% of the G143A allele. Of the 54 isolates tested in bioassays, 46 grew significantly at the recommended concentration, whereas 36 were able to grow at a fourfold higher concentration of quinoxyfen. Proquinazid showed more significant inhibition than quinoxyfen, suggesting that there is no cross-resistance between these two members of the azanaphthalene group. Unsatisfactory effect of metrafenone and pyriofenone at recommended concentrations was observed in 29 of 41 isolates. These isolates grew readily at four times higher concentrations of metrafenone and pyriofenone, indicating the cross-resistance between them. Overall, the results of this study suggest that resistance to QoIs has developed and is widespread in commercial vineyards, requiring growers to exclude them completely from powdery mildew management. The performance of proquinazid in the field was not affected, making it suitable for powdery mildew control. Special attention and extensive monitoring should be directed to metrafenone and pyriofenone, as cross-resistance has been found at certain sites where they have been used intensively over the past decade.
•Sensitivity of Erysiphe necator populations to different fungicides was studied.•Low efficacy of QoI, azanaphthalene and aryl-phenyl ketone fungicides was found.•The G143A mutation detected by qPCR analysis was prevalent in most samples.•Cross-resistance between metrafenone and pyriofenone was observed.•Proquinazid was effective for quinoxyfen-resistant powdery mildew populations.
This paper points out benefits for the national economy from construction of biogas plants (BgP ) - especially important for countries of the Pannonia Plain. Research data show that BgP has the most ...favorable effects on GDP of the national economy - compared to other renewable sources. Benefits from BgP for the national economy are: reducing CO2 emissions and municipal waste disposing, fewer imports of electricity, gas, and oil, significantly better economic performance in energy sector, balancing functioning of the national electricity system, hiring domestic companies and activating domestic resources and use of biogas in transport.
This paper points out the benefits for the local community from the construction of biogas power plants (BgP) - which are no from using other renewable energy sources. Benefits from BgP for local ...community are: additional income to local farmers, higher level of agro technologies in the village, strengthening social cohesion, ecological disposal of rural waste, electricity and heat production, organic fertilizer, hiring local labor and better quality of life for all inhabitants. In paper presented and important elements for planning the construction of biogas power plants.
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