Aleksa Obradovic

Aleksa Obradovic
University of Belgrade · Faculty of Agriculture

PhD

About

107
Publications
31,945
Reads
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1,790
Citations
Citations since 2017
32 Research Items
1053 Citations
2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250
2017201820192020202120222023050100150200250
Additional affiliations
October 2004 - present
University of Belgrade
Position
  • Professor (Full)
April 2001 - November 2002
University of Florida
Position
  • PostDoc Position
March 1989 - March 2001
Institute for Vegetable Crops
Institute for Vegetable Crops
Position
  • Plant pathologist

Publications

Publications (107)
Article
During May 2016 severe blight symptoms were observed in several raspberry and blackberry fields in Serbia. A total of 22 strains were isolated: 16 from symptomatic raspberry shoots, two from asymptomatic raspberry leaves, and four from symptomatic blackberry shoots. Additionally, eight raspberry strains, isolated earlier from two similar outbreaks...
Article
Full-text available
Bacterial fruit blotch and seedling blight, caused by Acidovorax citrulli , 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...
Article
Full-text available
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 ana...
Article
Bacterial diseases of apple are less numerous compared to fungal diseases, but under favorable conditions they can cause enormous damage. This is especially true for fire blight of apple, which can, in some years, cause complete tree death of sensitive cultivars. Fire blight has been present in Serbia for more than 30 years. Growing sensitive apple...
Chapter
Crop yield loss due to bacterial plant pathogens need to be reduced to increase global food production demand. Currently available disease management strategies involving copper-based bactericides and antibiotics are losing efficacy due to development of resistance in bacteria. There is long familiar demand of environmentally friendly and sustainab...
Article
Leaf spot of pepper was observed on different pepper cultivars in central Montenegro during summer and early autumn in three consecutive growing seasons (2017 - 2019). Necrotic spots were numerous, varying in size, irregular in shape, brown, and surrounded by a weak halo. The most intensive symptoms were observed on lower leaves. In conditions cond...
Article
Xanthomonas arboricola pv. corylina is the causal agent of bacterial blight of hazelnut. The bacterium is listed as A2 quarantine pathogen in Europe since 1978 and on the Regulated Non-Quarantine Pest (RNQP) list since 2020. Three strains from various geographic regions and isolated at different times were sequenced using a hybrid approach with sho...
Article
Arugula (Eruca vesicaria subsp. sativa (Miller) Thell., syn. Brassica eruca L.), is an annual cruciferous crop that is increasingly grown for fresh consumption in Serbia. In November 2018, a few detached leaves of cultivated arugula originating from a local producer, showing necrotic lesions, were observed in a fresh vegetable market in Belgrade, S...
Article
During the surveys of stone fruit orchards in 2017 and 2018, yellow, convex and mucoid bacterial colonies were isolated from peach and sweet cherry samples showing leaf and fruit spot and twig necrosis. We selected 37 g negative, HR positive strains. They were strictly aerobic, oxidase negative and catalase positive, hydrolyzed esculin and did not...
Article
Full-text available
Background: The species Xanthomonas arboricola comprises up to nine pathovars, two of which affect nut crops: pv. juglandis, the causal agent of walnut bacterial blight, brown apical necrosis, and the vertical oozing canker of Persian (English) walnut; and pv. corylina, the causal agent of the bacterial blight of hazelnut. Both pathovars share a c...
Article
Full-text available
Xanthomonads, members of the family Xanthomonadaceae, are economically important plant pathogenic bacteria responsible for infections of over 400 plant species. Bacteriophage-based biopesticides can provide an environmentally friendly, effective solution to control these bacteria. Bacteriophage-based biocontrol has important advantages over chemica...
Article
In July 2020, symptoms of leaf and fruit spot were observed on two-year old apricot plants (Prunus armeniaca L.), cultivar Rubista in plantation covering approximately 0,5 ha near Podgorica, central Montenegro. The intensity of infection on leaves was more than 70%. Initially, leaf spots were mainly circular, 2 to 5 mm in diameter, water-soaked, su...
Article
Full-text available
In Montenegro, stone fruit species are grown on intensive and semi-intensive commercial plantations. However, almond production is mainly organized on family gardens and for household consumption. During two seasons (2017–2018), we surveyed apricot, peach, nectarine, sweet cherry, Japanese plum, and almond orchards for the presence of bacterial dis...
Article
"Candidatus Liberibacter solanacearum" is a gram-negative, fastidious bacterium that inhabits and multiplies in the phloem of host plants. The bacterium causes economically important diseases of solanaceous crops such as "zebra chips" of potatoes, and chlorotic weakening of cultivated plants of the Apiaceae family. Beside potatotes, this pathogen c...
Book
Full-text available
The term “endophytes” usually refers to communities of microorganisms, typically bacteria or fungi, which colonize the internal portion of plants, mainly vascular tissues, interacting with the host in either beneficial or neutral mode. The scientific community customarily classifies endophytes into three main subsets based on facultative, obligate...
Article
Full-text available
With the increasing social concern in avoiding, or at least reducing, the application of pesticides and chemical fertilizers, in favor of sustainable eco-friendly alternatives, the search for beneficial microorganisms and microbial-derived compounds has become one of the most popular Research Topics in the field of plant-microbe interactions (Cardo...
Article
Bacterial stalk soft rot have been repeatedly observed on maize plants in several commercial fields in northern part of Serbia in the period of 1990 to 2014. The occurrence of the disease corresponded with warm weather and increased humidity. Etiological studies of the diseased tissue constantly resulted in isolation of pectolytic bacterial strains...
Article
Bacterial spot caused by Xanthomonas euvesicatoria is one of the most devastating pepper diseases in Serbia. Questionable seed quality, climatic conditions, and frequent irrigation during summer favour the disease occurrence and spread. The available management practices do not provide adequate disease control. Therefore, development of alternative...
Article
Full-text available
Pseudomonas syringae sensu stricto (phylogroup 2; referred to as P. syringae) consists of an environmentally ubiquitous bacterial population associated with diseases of numerous plant species. Recent studies using multilocus sequence analysis have indicated the clonal expansion of several P. syringae lineages, located in phylogroups 2a and 2b, in a...
Article
Full-text available
Three PCR methods, referred in this study as „conventional“, „nested“ and „chromosomal“ PCR and suggested for routine detection of Erwinia amylovora in pure culture and plant material, were evaluated according to their specificity and sensitivity. Specificity of PCR methods was analyzed by using 42 strains of E. amylovora, originating from differen...
Article
Full-text available
Xanthomonas euvesicatoria phage KΦ1, a member of Myoviridae family, was isolated from the rhizosphere of pepper plants showing symptoms of bacterial spot. The phage strain expressed antibacterial activity to all X. euvesicatoria strains tested and did not lyse other Xanthomonas spp., nor other less related bacterial species. The genome of KΦ1 is do...
Article
Full-text available
The diversity of 30 Erwinia amylovora strains, isolated from quince, pear and apple trees on 14 localities in Serbia, was studied using bacteriological and molecular methods. In pathogenicity tests, all strains caused necrosis and oozing of bacterial exudate on inoculated immature pear, cherry and plum fruits, and induced hypersensitive reaction in...
Chapter
This book contains 20 chapters and is divided into 4 parts focusing on genetic resources and improvement, ecophysiology and production, pests and diseases and their management and harvesting, processing and utilization of sweet and sour cherries.
Conference Paper
Full-text available
The International Research Consortium POnTE (Pest Organisms Threatening Europe) is being funded by the European Commission under the Horizon 2020 programme to investigate four pathogens (i.e. Xylella fastidiosa, Candidatus Liberibacter solanacearum, Hymenoscyphus fraxineus and Phythophthora spp.) representing a major threat to strategic crops and n...
Article
Full-text available
The International Research Consortium POnTE (Pest Organism Threatening Europe) is being funded by the European Commission under the Horizon 2020 programme to investigate four pathogens (i.e. Xylella fastidiosa, Candidatus Liberibacter solanacearum, Hymenoscyphus fraxineus and Phythophtora spp.) representing a major threat to strategic crops and nat...
Conference Paper
Full-text available
The International Research Consortium POnTE (Pest Organism Threatening Europe) is being funded by the European Commission under the Horizon 2020 programme to investigate four pathogens (i.e. Xylella fastidiosa, Candidatus Liberibacter solanacearum, Hymenoscyphus fraxineus and Phythophtora spp.) representing a major threat to strategic crops and nat...
Article
Grapevine crown gall caused by Allorhizobium vitis, or less frequently by Agrobacterium tumefaciens complex and Rhizobium rhizogenes, may seriously impact production in nurseries and vineyards worldwide. Although rapid and efficient detection and identification of tumorigenic bacteria is facilitated by PCR-based methods, high genetic diversity of t...
Article
Bacterial spot, caused by Xanthomonas euvesicatoria, is widely spread disease of pepper in Serbia. When weather conditions are favorable for disease development, pepper producers do not have adequate resources to control this pathogen. Copper based bactericides registered in our country are not effective enough. However, effective protection could...
Article
During the last 3 years, crown gall disease was observed in some young raspberry plantations throughout Serbia, causing considerable economic losses. Based on biochemical and physiological tests, PCR targeting the 23S rRNA gene, and 16S rRNA and recA gene sequence analysis, at least two different species were identified as causal agents of disease....
Article
Two plant-tumorigenic strains KFB 330(T) and KFB 335 isolated from galls on raspberry (Rubus idaeus) in Serbia, and a non-pathogenic strain AL51.1 recovered from a cherry plum (Prunus cerasifera) tumor in Poland, were genotypically and phenotypically characterized. Phylogenetic reconstruction based on 16S rDNA placed them within the genus Agrobacte...
Article
Full-text available
The antifungal effects of thyme, cinnamon bark and clove bud essential oils (EOs) were investigated in vitro on Colletotrichum acutatum mycelial growth, conidial germination, appressoria formation, and in vivo on strawberry fruit disease incidence. All tested EOs, incorporated in potato-dextrose agar, inhibited C. acutatum mycelial growth, and had...
Article
Aims:To analyze genetic diversity and epidemiological relationships among 54 strains of Allorhizobium vitis isolated in Europe during an eight-year period and to assess the relative contribution of mutation and recombination in shaping their diversity. Methods and results: By using random amplified polymorphic DNA (RAPD) PCR, strains studied were d...
Article
Full-text available
Tumorigenic strains of Agrobacterium spp. are responsible for crown gall disease of numerous plant species. We present here draft genome sequences of nonpathogenic Agrobacterium nepotum strain 39/7T (CFBP 7436T, LMG 26435T), isolated from crown gall tumor on Prunus cerasifera, and tumorigenic Agrobacterium sp. strain KFB 330 (CFBP 8308, LMG 28674),...
Article
Serious outbreaks of grapevine crown gall disease were observed in major Serbian viticultural regions during the last five years. Tumorigenic Agrobacterium vitis was identified as a causal agent by using conventional bacteriological and molecular tests. The 36 studied strains of A. vitis showed homogeneous biochemical and physiological characterist...
Article
Full-text available
Recent genome analysis of Erwinia amylovora, the causal agent of fire blight disease on Rosaceae, has shown that the chromosome is highly conserved among strains and that plasmids are the principal source of genomic diversity. A new circular plasmid, pEA68, was found in E. amylovora strain 692 (LMG 28361), isolated in Poland from Sorbus (mountain a...
Article
Full-text available
Soft rot symptoms were observed on broccoli plants in several commercial fields in the western part of Serbia. Six strains of bacteria were isolated from diseased tissues and identified as Pectobacterium carotovorum subsp. carotovorum using conventional bacteriological and molecular methods. All strains were non-fluorescent, gram-negative, facultat...
Article
In this study, three bacterial DNA extraction procedures were compared prior to real-time PCR. Healthy pear leaves and twigs were crushed in antioxidant maceration buffer and spiked with Erwinia amylovora to final concentrations from 2.1 × 106 to 2.1 × 101 cells ml-1. Bacterial DNA was extracted from aliquots of spiked crude extracts using (i) isop...
Article
In search for an alternative to chemical control of fire blight, we isolated seven bacteriophages specific to E. amylovora. Three phages were isolated from water, three from symptomless pear leaves and one from apple leaves with characteristic fire blight symptoms. Host-range studies showed that the phages differed in the ability to lyse 40 strains...
Article
In September 2012, soft rot symptoms on broccoli (Brassica oleracea L. var. italica Plenck) were observed in several commercial fields in the western part of Serbia. Following the first harvest, water-soaked areas developed on broccoli stem tissue and progressed into soft rot decay of entire plants. The incidence of disease was approximately 30%. I...
Article
Crown gall, caused by tumorigenic strains of Agrobacterium spp., is considered one of the most important diseases in stone fruit nurseries throughout the world. Since the crown gall disease has not been studied extensively in Serbia for more than 30 years, the objective of this study was to isolate, identify and characterize the bacterium associate...
Article
Full-text available
The use of bacteriophages as an effective phage therapy strategy faces significant challenges for controlling plant diseases in the phyllosphere. A number of factors must be taken into account when considering phage therapy for bacterial plant pathogens. Given that effective mitigation requires high populations of phage be present in close proximit...
Article
Full-text available
Soil-based root applications and attenuated bacterial strains were evaluated as means to enhance bacteriophage persistence on plants for bacterial disease control. In addition, the systemic nature of phage applied to tomato roots was also evaluated. Several experiments were conducted applying either single phages or phage mixtures specific for Rals...
Article
Forty Erwinia amylovora strains originating from different host plants and locations in Serbia and one strain from Montenegro were characterized by conventional, automated and molecular techniques. All strains were Gram-negative, nonfluorescent, facultative anaerobes, oxidase negative, levan positive, produced necrotic lesions followed by bacterial...
Article
Monilinia fructicola (G. Winter) Honey is a causal agent of brown rot of stone fruits, occasionally affecting pome fruits as well. The pathogen is commonly present in North and South America, Oceania, and Asia, but listed as a quarantine organism in Europe (4). After its first discovery in France in 2001, its occurrence has been reported in Germany...
Article
In November 2010, a serious outbreak of crown gall disease was observed on 3-year-old grapevine (Vitis vinifera L.) cv. Cabernet Sauvignon grafted onto Kober 5BB rootstock in two commercial vineyards located in the South Banat District in Serbia. Large, aerial tumors were visible above the grafting point on grapevine trunks, and in most cases, the...
Article
Full-text available
Timley and reliable detection of the hazelnut pathogen Xanthomonas arboricola pv. corylina (Xac) is essential for the production of good quality disease-free planting material. In order to improve knowledge on diagnostic tools for this quarantine bacterium, the effectiveness of laboratory methods recomended by EPPO and additional modified procedure...
Article
Full-text available
Bacterial spot, caused by either Xanthomonas euvesicatoria (Xe-Group A), X. vesicatoria (Xv-Group B), X. perforans (Xp-group C) and X. gardneri (Xg-Group D), formerly known as X. campestris pv. vesicatoria, is considered one of the most common pepper and tomato diseases in Serbia. So far, 11 physiological races of X. euvesicatoria bacterium were de...
Article
Full-text available
Plants have evolved different strategies to protect themselves against pathogen infections. These strategies are classified as either passive or active, depending on whether they are constitutive barriers or triggered upon pathogen attack. Induced plant resistance is a type of active resistance and is defined as a state of enhanced defensive capaci...
Article
Full-text available
Due to an overlapping host range, similar symptomatology and many common characteristics,Pseudomonas syringae pathovars originating from stone fruits can easily be misidentified.In order to select tests for rapid and efficient differentiation of P. s. pvs. syringae,morsprunorum and persicae, we studied the suitability and differentiating potential...
Article
Full-text available
In 2010, a serious outbreak of crown gall disease was observed on grapevines (Vitis vinifera L. cv. Cabernet Sauvignon) in several commercial vineyards located in the Vojvodina province, Serbia. Bacteria were isolated from the young tumor tissue on nonselective YMA medium and five representative strains were selected for further identification. Tum...
Article
Full-text available
Host range, plaque morphology, thermal inactivation point, genome size and restriction fragment patterns of ten bacteriophage isolates originating from soil, pepper seed and irrigation water collected from five localities in Serbia were studied. The bacteriophage isolates were se-lected based on their specificity to Xanthomonas euvesi-catoria, caus...
Article
Forty Erwinia amylovora strains originating from different host plants and locations in Serbia and one strain from Montenegro were characterized by conventional, automated and molecular techniques. All strains were Gram-negative, nonfluorescent, facultative anaerobes, oxidase negative, levan positive, produced necrotic lesions followed by bacterial...
Article
A collection of 41 Erwinia amylovora strains isolated from 8 plant species at 13 locations in Serbia and one location in Montenegro was tested and their relationship was determined based on carbohydrate metabolism and fatty acid composition. Metabolism of carbon compounds was tested using the Biolog GN MicroPlate system. After 24 h of incubation, t...
Article
Full-text available
Due to the difficulties in differentiation of phytopathogenic Agrobacterium spp. and lack of a standardized protocol, we carried out selection and evaluation of suitable methods based on the bacterial physiological, genetic and pathogenic properties. Strains of Agrobacterium tumefaciens, A. rhizogenes and A. vitis were differentiated using standard...
Article
Full-text available
Automated method of fatty acid analysis was used to identify and study heterogeneity of 41 Erwinia amylovora strains, originating from 8 plant species grown in 13 locations in Serbia and one in Montenegro. All strains contained 14:0 3OH fatty acid,characteristic for the “amylovora” group. According to fatty acid composition 39 strains were identifi...
Article
The bacterium Xylella fastidiosa, a xylem-inhabiting, vector-transmitted, Gram-negative, very slow growing bacterium, was cultured and properly described for the first time in 1987 in the USA as the cause of Pierce's dis-ease (PD) of grapevine, Vitis vinifera (disease observed already in 1884) and as the cause of phony peach dis-ease (PPD) in peach...
Article
Full-text available
During spring and summer of 2008, 101 bacterial strains was isolated from the diseasedpepper leaves collected from different pepper growing areas in the Republic of Serbia. Theaim of this research was to characterize the isolated strains and determine their taxonomicposition according to the most recent nomenclature.Pathogenic, biochemical and phys...
Article
Full-text available
Effects of the volatile phase of thyme, cinnamon and clove essential oils onColletotrichum acutatum were investigated. Mycelial disc was placed in the center of thePetri dish (V=66 ml) containing PDA. Different volumes of either non- or ethanol-dilutedessential oils were placed on the inner side of the dish cover to obtain final concentrationsof 15...
Article
Tomato bacterial spot, caused by Xanthomonas spp. complex, is a constant threat to tomato (Solanum lycopersicum) commercial production, but is especially severe in Florida and the southeastern US when weather conditions become conducive for disease development. In an effort to develop more sustainable strategies for reducing severity of the disease...
Article
Full-text available
Control of plant pathogenic bacteria is a serious problem in production of many agricultural crops. High multiplication rate, adaptability and life inside plant tissue make bacteria unsuitable and inaccessible for most of control measures. Consequently, the list of bactericides available for plant protection is very short. Lately, biological contro...
Article
Full-text available
Bacterial strains were isolated from above- and underground parts of diseased calla plants originating from different localities in Serbia and one locality in Montenegro. They were characterized by studying their pathogenic, cultural, biochemical and physiologicalcharacteristics. All investigated strains caused soft rot of calla leaf stalks, potato...
Article
The causal agent of bacterial spot of capsicum and tomato grown in different regions in Yugoslavia was investigated. Isolations were made from diseased material collected in recent years. The biochemical and physiological characteristics of isolated bacteria were studied by standard bacteriological tests. The race of the pathogen was determined on...
Article
In 1989 Erwinia amylovora was confirmed to be a pathogen of pear and quince in Serbia. Subsequently, apple, firethorn, hawthorn, Mespilus spp., Cotoneaster horisontalis and Cheanomeles spp. were confirmed as hosts of the pathogen. During the summer 2005, fire blight symptoms were observed on Sorbus spp. for the first time in the south-eastern Serbi...
Article
Soft rot and wilt symptoms were noticed on 2-year-old seed cabbage plants grown in field crops. Soft rot Erwinia was isolated from the diseased tissues. Pathogenicity tests showed that the bacterium effectively colonised different vegetable species and sunflower, indicating a wide host range.Pathogenicity, morphological, biochemical and physiologic...
Chapter
Bacterial diseases of plants play an important role in the world’s agriculture by reducing yield and marketability of particular crops or by limiting their production in areas with environmental conditions conducive for disease development. Plant pathogenic bacteria present many obstacles in developing efficient plant protection practices. In spite...
Chapter
An increase of mushroom production in Serbia contributed to the increased incidence and importance of problems related to mushroom pathology. Apart from the decline in mushroom quality due to a maturation or senescence process, mushroom caps are often colonized by mycopathogenic microorganisms causing growth deformation and decay. From samples of d...
Chapter
Collapse of shoot tips and upper leaves, followed by wilting and dieback of entire shoots were observed on raspberry plants (cv. Willamette) grown in Serbia. Characteristic symptoms associated with oozing out from the diseased tissue indicated bacteria as a possible causal agent of the disease. Isolations resulted in bacterial isolates belonging to...