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Lactobacillus plantarum, one of the most widespread lactic acid bacteria, exert a strong antagonistic activity against many microorganisms. The present study was conducted to determine in vitro and in situ antagonistic potential of L. plantarum (DSM 20174) for control postharvest decay caused by phytopathogenic fungi: Aspergillus flavus, Colletotrichum acutatum, Colletotrichum gloeosporioides, and Fusarium avenaceum. The results obtained in in vitro assays showed that L. plantarum had a stronger inhibitory effect on spore germination than on mycelia growth of all tested fungi. After 3 days of incubation, the diameter of inhibition zones ranged from 11.67 mm for C. gloeosporioides to 14.67 mm for C. acutatum. The bacterial suspension of L. plantarum significantly inhibited conidial germination of all postharvest pathogens (89.62-97.61%). In situ assays showed that treatment with L. plantarum efficiently inhibited necrosis ranging from 42.54% for C. acutatum to 54.47% for A. flavus. The disease incidence in L. plantarum treated fruits was statistically significantly lower than in the positive control for all fungi tested (P<0.05). The presented data demonstrate the antagonistic potential of L. plantarum (DSM 20174) and indicate the possibility of using this bacterial strain as a biological agent to control postharvest fungal pathogens. [ABSTRACT FROM AUTHOR]

Anthracnose caused by the fungus Colletotrichum orbiculare is one of the most significant diseases of Cucurbitaceae. In Serbia watermelon fruits with typical anthracnose lesions were collected during the year of 2015. Affected fruits showed sunken, dark brown to black lesions with orange conidial masses produced in black acervuli. In an attempt to identify the causal organism, small pieces of necrotic tissue were surface sterilized and placed on potato dextrose agar (PDA). Macroscopic and microscopic morphologicaly characteristics of three isolates were observed after growth on PDA for 7 days at 25 °C under a 12 h light/dark cycle. Fungal colonies developed white, grey to black dense aerial mycelium. Conidia were hyaline, aseptate, straight and cylindrical to clavate, 9-12.5 μm x 4-5.5 µm. Fungal isolates were also characterized by sequencing of the internal transcribed spacer (ITS) rDNA region using ITS1F/ITS4 primers and β-tubuline 2 gene using T1/Bt2b primers. The nucleotide sequences were deposited in GenBank (ITS Acc. No. KT454386, KT454387 and KT454388; β-tubuline 2 gene Acc. No. KT581236, KT581237 and KT581238). BLAST analysis of ITS and β-tubuline 2 gene sequences showed that our isolates were 100% identical to other C. orbiculare in NCBI GenBank. Pathogenicity test was conducted on symptomless, detached watermelon fruits. All tested isolates caused anthracnose lesions on watermelon fruits after 10 days of incubation. Trichoderma harzianum (DSM 63059) and Gliocladium roseum (DSM 62726) were evaluated in vitro for their antagonistic potential against C. orbiculare. The results of this study identify T. harzianum and G. roseum as promising biological control agents (BCAs) for further testing against anthracnose disease on watermelon fruits. [ABSTRACT FROM AUTHOR]

Highlights: [•] Total antimicrobial activity of two isolates of Bacillus sp. was characterized. [•] The strains inhibit the growth of phytopathogenic bacteria in vitro. [•] Very strong antifungal activity was confirmed in vitro and in vivo for both strains. [•] Detected compounds belong to the class of antimicrobial lipopeptides. [•] Mass spectrometry identified compound that corresponds to surfactin. [ABSTRACT FROM AUTHOR]

Lemon fruits are an important source of vitamin C, potassium, folate, carotenoids, polyphenols, coumarins and terpenes. These lemon compounds have antioxidant and anti-inflammatory properties which have beneficial effects on human health. This research aimed to elucidate the etiology of blue and green molds detected on lemon fruits in Serbia. Using integrative identification approach, the obtained isolates were characterized from morphological, physiological, molecular, phylogenetic and pathological aspects. Colony growth and morphology were examined on Czapek yeast autolysate agar (CYA), Malt extract agar (MEA) and Creatine sucrose agar (CREA), and on CYA at two additional incubation temperatures (5 and 37 °C). For molecular identification, ITS and partial β-tubulin (BenA) genes were sequenced. Phylogenetic relationships were investigated using maximumlikelihood method. A pathogenicity test was carried out and the possible difference in pathogenicity among isolates was assessed with analysis of variance (ANOVA) and subsequent Tukey's test. Four species were identified: Penicillium expansum, Penicillium digitatum, Penicillium polonicum and Talaromyces rugulosus. All four species proved to be pathogenic on lemon fruits, producing symptoms similar to those observed on naturally infected fruits. The results of this study are the first records of the beforementioned Penicillium/Talaromyces species as postharvest pathogens on lemon fruits in Serbia and the first world report of T. rugulosus as phytopathogenic on the same host. [ABSTRACT FROM AUTHOR]

Mandarin fruits are one of the most popular among the Citrus genus. They are consumed because of their nutritional and health benefits, as well as pleasant taste and smell. This paper describes the identification and characterization of Penicillium expansum, isolated from molded mandarin fruits. The obtained isolates were cultivated on five media [Czapek Yeast Autolysate agar (CYA), MEA (Malt extract agar), Creatine sucrose agar (CREA), Yeast extract sucrose agar (YES), and Oatmeal agar (OA)] and at five different incubation temperatures (5, 15, 25, 30, and 37 °C). Isolates were sequenced for two molecular loci: internal transcribed spacer and beta-tubulin. Based on the results from morphological, physiological, molecular, and phylogenetic analyses, the recovered isolates were identified as P. expansum. The isolated species was confirmed as pathogenic to mandarin fruits in a pathogenicity test. To the best of our knowledge, this is the first report of P. expansum as a postharvest pathogen of mandarin fruit in Serbia. [ABSTRACT FROM AUTHOR]

Blackberry cane diseases with the symptoms of necrosis, canker, and wilting are caused by several fungi worldwide. Surveys conducted from 2013 to 2016 in Serbia revealed the occun'ence of Gnomoniopsis idaeicola. the causal agent of cane canker and wilting, which was found to be distributed in almost half of the surveyed orchards, in three blackbeny cultivars, and with disease incidence of up to 80%. Wide distribution and high disease incidence suggest that G. idaeicola has been present in Serbia for some time. Out of 427 samples, a total of 65 G. idaeicola isolates were obtained (isolation rate of 34.19%). Reference isolates, originating from different localities, were conventionally and molecularly identified and characterized. G. idaeicola was detected in single and mixed infections with fungi from genera Paraconiothyrium, Colletotrichum, Diaporthe, Botryosphaeria, Botrytis, Septoria, Neofusicoccum, and Discostroma, and no diagnostically specific symptoms could be related directly to the G. idaeicola infection. In orchards solely infected with G. idaeicola. blackberry plant mortality was up to 40%, and yield loses were estimated at 50%. G. idaeicola isolates included in this study demonstrated intraspecies diversity in morphological, biological, pathogenic, and molecular features, which indicates that population in Serbia may be of different origin. This is the first record of a massive outbreak of G. idaeicola infection, illustrating its capability of harmful influence on blackberry production. This study represents the initial step in studying G. idaeicola as a new blackberry pathogen in Serbia, aiming at developing efficient control measures. [ABSTRACT FROM AUTHOR]

During past few years a symptoms of plum and cherry bud necrosis were observed in some regions with significant cherry production in Serbia. Gram negative, fluorescent, oxidative bacterial strains were isolated from the margin of necrotic tissue. All investigated strains are levan and HR positive, while negative results are recorded in oxidase, pectinase and arginin dihydrolase tests (LOPAT+--- +). Symptoms similar to those observed in natural infection were obtained after artificial inoculation of cherry leaf scares and dormant one year old cherry shoots. Investigated strains as well as reference strain of P. syringae pv. morsprunorum cause the superficial necrosis on artificially inoculated immature cherry fruits, but negative results were recorded in immature pear and lemon fruit tests as well as syringae leaves and bean pods. Gelatin and aesculin tests were negative and tyrosinase and tartrate were positive. Investigated strains isolated from necrotic cherry buds had identical REP-PCR pattern with reference strain of P. syringae pv. morsprunorum. On the basis of obtained results, it was concluded that this bacterium is causal agent of cherry trees bud necrosis in Serbia. [ABSTRACT FROM AUTHOR]

Bean production is threaten by phytopathogenic bacteria causing agents of blights, Xanthomonas axonopodis pv. phaseoli (Xap) and Pseudomonas savastanoi pv. phaseolicola (Psp). Since there is no satisfactory chemical control for the disease, the recommended measures are preventive and include use of healthy seed, crop rotation, deep plowing and use of resistant cultivars. In this work we involved a detection method for isolation of Xap and Psp from bean seed to semi-selective medium Milk Agar Tween (MT). On this medium, Xap formed yellow, mucoid and convex colonies with two hydrolysis zones (less milk and more enlightened), and Psp formed whitish-cream, flat and round colonies. The identification of Xap and Psp was confirmed using the ELISA and PCR. Due to its selectivity, easy preparation and possibility of simultaneous detection of bacteria Xap and Psp, MT medium can be recommended for routine test of seed health for local seed or seed from import. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]