Research microclimate features on the dairy farm

Mikroklimatski uvjeti u stajama su temperatura zraka, vlaga zraka, brzina strujanja zraka, osvijetljenost, prašina, mikroorganizi i štetni plinovi te ih treba održavati u optimalnim granicama. Istraživanje mikroklimatskih parametara rađeno je na farmi mliječnih krava „Landia“ u Tordincima. Tijekom ljetnih mjeseci je smanjena proizvodnja mlijeka uslijed toplinskog stresa što suzbija veliki genetski napredak postignut u povećanju proizvodnje mlijeka. U istraživanju proizvodnja mlijeka kretala se od 20,10 do 32,8 kg. Odstupanja temperature zraka od optimalne vrijednosti (5-25 °C) tijekom ljetnih mjeseci su bile od 1,5 do 9 °C. Tijekom siječnja, veljače, ožujka, studenog i prosinca su odstupanja temperature od optimalnih bile su manje za -5 do -9 °C. Jedini mjesec kada temperature nisu odstupale od optimalnih je bio mjesec travanj. Proizvodnja mlijeka bila je najviša kada su temperature i vlaga zraka bili u povoljnom odnosu (THI <72) odnosno tijekom hladnijeg razdoblja godine, u jesen i zimu. Temperaturno humidni indeks se koristi za procjenu zahtjeva za hlađenje mliječnih krava kako bi se poboljšala učinkovitost upravljanja strategijama za smanjivanje stresa uzrokovanog vrućinom. Utvrđena je velika zastupljenost razdoblja tijekom ljeta kada su vrijednosti THI iznosila je od 65 do 75, kada su krave bile izložene nepovoljnim omjerima temperature i vlage zrakaMicroclimate conditions in the stall are air temperature, air humidity, air velocity, ambient light, dust, germs and harmful gases and should be maintained within the optimal range. Research microclimate parameters was carried out on a dairy farm "Landia" in Tordinci. During the summer months was reduced milk production due to heat stress which suppresses the great genetic progress in increasing milk production. The study milk production ranged from 20.10 to 32.8 kg. Temperature deviation from the optimum value (5-25 °C) during the summer months were from 1.5 to 9 °C. During January, February, March, November and December are deviations from the optimal temperature were less of -5 to -9 °C. The only month when the temperature did not differ from the optimal was the month in April milk production was highest when the temperature and humidity were favorable compared (THI<72) or during cooler periods of the year, in the fall and winter. Temperature humid index is used to assess the requirements for cooling dairy cows to enhance the effectiveness of management strategies to reduce heat stress. There was a large representation during the summer period when the value of THI was 65-75 when the cows were exposed to unfavorable ratios of temperature and humidity

Bakterioze krompira - crna trulež prizemnog dela stabla ('crna noga') i vlažna trulež krtola krompira

Bacterial diseases are very common in potato crops, especially when weather conditions are favourable for the emergence and spread of infection. Bacteria belonging to the Pectobacterium and Dickeya genera, the causal agents of the blackleg and tuber soft rot of potato, are economically important pathogens that affect potato production worldwide, as well as in our country. According to recent classification, pectolytic bacteria, the pathogens of potato, have been differentiated as Pectobacterium atrosepticum, P. carotovorum subsp. carotovorum, P. carotovorum subsp. brasiliense, P. wasabiae and several Dickeya spp. The disease occurs on potato plants and tubers in the field, or during potato storage or transportation, thereby reducing yield and quality. The aim of this paper is to point to the distribution and economic importance of the blackleg and tuber soft rot of potato, as well as the characteristics of the pathogens. Information about symptoms and epidemiology of the disease are important for an accurate disease diagnosis and pathogen identification, contributing to the timely and successful protection strategy.Oboljenja bakteriozne prirode veoma su česta u usevima krompira, posebno kada vremenski uslovi pogoduju nastanku i širenju infekcije. Među ekonomski značajnim bakterijama koje ugrožavaju proizvodnju krompira u svetu i u našoj zemlji, izdvajaju se prouzrokovači crne truleži prizemnog dela stabla ('crna noga') i vlažne truleži krtola krompira, pripadnici rodova Pectobacterium i Dickeya. Prema najnovijoj klasifikaciji, pektolitičke bakterije, patogeni krompira, diferencirane su u vrste Pectobacterium atrosepticum, P. carotovorum subsp. carotovorum, P. carotovorum subsp. brasiliense, P. wasabiae i nekoliko Dickeya spp. Bolest se može pojaviti na biljkama i krtolama u polju ili na krtolama tokom transporta i u skladištu, umanjujući prinos useva i kvalitet krtola. Cilj ovog rada je da se prikaže rasprostranjenost i ekonomski značaj crne truleži prizemnog dela stabla i vlažne truleži krtola krompira, kao i osnovne karakteristike patogena. Poznavanje simptomatologije i epidemiologije oboljenja je od posebnog značaja za pravilnu dijagnozu oboljenja i identifikaciju patogena, što doprinosi pravovremenoj i uspešnoj zaštiti

Identification of Agrobacterium vitis as a causal agent of grapevine crown gall in Serbia

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. Tumorigenic (Ti) plasmid was detected in all strains by PCR using primers designed to amplify the virC pathogenicity gene, producing a 414-bp PCR product. The strains were identified as Agrobacterium vitis using differential physiological and biochemical tests, and a multiplex PCR assay targeting 23S rRNA gene sequences. In the pathogenicity assay, all strains induced characteristic symptoms on inoculated tomato and grapevine plants. They were less virulent on tomato plants in comparison to the reference strains of A. tumefaciens and A. vitis. [Ministarstva nauke Republike Srbije, br. III46008: Development of integrated management of harmful organisms in plant production in order to overcome resistance and to improve food quality and safety

Diferencijacija Pseudomonas syringae patogenih varijeteta poreklom iz koštičavih voćaka

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 of some standard bacteriological and molecular methods. Differentiation of the strains was performed using LOPAT, GATTa and ice nucleation tests, nutrient sucrose broth growth and utilization of various carbon sources. PCR method enabled the detection of toxin-producing genes: syrB and syrD in P. s. pv. syringae, and cfl gene in P. s. pv. morsprunorum race 1. Syringomycin production by pv. syringae was confirmed in bioassay using Geotrichum candidum, Saccharomyces cerevisiae and Rhodotorula pilimanae as indicator organisms. Pathogenicity test on lemon and immature nectarine fruits, as well as on string bean pods, showed different intensity of reaction of the inoculated material which could separate pv. syringae from the other two pathovars. PCR-based repetitive sequences, Rep-PCR with REP, ERIC and BOX primers revealed different genetic profiles within P. syringae pathovars.Patogeni varijeteti Pseudomonas syringae poreklom sa koštičavih voćaka poseduju brojne zajedničke karakteristike u pogledu kruga domaćina, simptomatologije i biohemijskofizioloških osobina, što otežava njihovu identifikaciju. U cilju odabira testova pogodnih za brzu i pouzdanu identifikaciju P. s. pv. syringae, morsprunorum i persicae, primenjeni su standardni bakteriološki i molekularni testovi. Diferencijacija sojeva izvršena je LOPAT i GATTa testovima, posmatranjem razvoja u hranljivom rastvoru sa saharozom, sposobnošću sojeva da formiraju čestice leda, kao i mogućnošću korišćenja različitih ugljenikovih jedinjenja. PCR metod korišćen je u detekciji gena odgovornih za proizvodnju toksina siringomicina kod soja P. s. pv. syringae (syrB i syrD geni) i koronatina kod soja P. s. pv. morsprunorum rase 1 (cfl gen). Proizvodnja siringomicina potvrđena je i biotestom, korišćenjem gljiva Geotrichum candidum, Saccharomyces cerevisiae i Rhodotorula pilimanae kao indikatora. Proverom patogenosti sojeva na plodovima limuna, nesazrelim plodovima nektarine i mahunama boranije, došlo je do ispoljavanja simptoma različitog intenziteta, na osnovu kojih se može izdvojiti pv. syringae od ostala dva patovara. Primenom Rep-PCR metode, uz korišćenje REP, ERIC i BOX prajmera, ustanovljene su razlike u genetskim profilima proučavanih P. syringae patogenih varijeteta

Prouzrokovači bakteriozne uvelosti paradajza i žute uvelosti (Stolbur) paprike i paradajza

Bacterial diseases are very common in tomato and pepper crops, especially under favourable weather conditions. One of the economically most important pathogens that affect tomato production worldwide is Ralstonia solanacearum, causal agent of bacterial wilt of tomato. The pathogen survives in soil and water. It colonizes xylem, clogs the vascular tissue preventing water movement throughout the stem, causing colapse of the infected plants. In addition, wilting of tomato and pepper can be caused by Candidatus Phytoplasma solani (Stolbur Phytoplasma). Main sources of infection with this pathogen are wild plants from where it is further transmitted by feeding of leafhopper vectors. The aim of this paper is to point to distribution and economic importance of those diseases, as well as characteristics of the pathogens. Information about symptoms and epidemiology of the disease are important for an accurate disease diagnosis and pathogen identification, which contributes to the timely and successful protection strategy.Oboljenja bakteriozne prirode veoma su česta u usevima paradajza i paprike, posebno kada vremenski uslovi pogoduju nastanku i širenju infekcije. Među ekonomski najznačajnijim bakterijama koje ugrožavaju proizvodnju paradajza u svetu, izdvaja se prouzrokovač bakteriozne uvelosti paradajza Ralstonia solanacearum. Patogen se dugo održava u zemljištu i vodi. Naseljava ksilem biljaka onemogućavajući protok vode, usled čega dolazi do pojave uvelosti. Osim ovog patogena, simptome uvelosti paradajza i paprike može takođe prouzrokovati Candidatus Phytoplasma solani (Stolbur fitoplazma). Ovo oboljenje prenosi se cikadama, dok su glavni izvori infekcije korovske biljke. Cilj ovog rada je da se prikaže rasprostranjenost i ekonomski značaj navedenih oboljenja paradajza i paprike, kao i osnovne karakteristike njihovih prouzrokovača. Poznavanje simptomatologije i epidemiologije oboljenja je od posebnog značaja za pravilnu dijagnozu oboljenja i identifikaciju patogena, što doprinosi pravovremenoj i uspešnoj zaštiti

Novi pravci zaštite paprike i paradajza od bakteriozne pegavosti

Bacterial spot, caused by bacteria that belong to Xanthomonas complex, is one of the widespread and economically important disease of pepper and tomato. Growing resistant genotypes, use of treatments based on copper compounds or streptomycin do not provide efficient control of this disease due to the appearance of new races of bacteria and development of strains resistant to antibiotics and copper compounds. Pepper and tomato producers do not have adequate resources for pathogen control since standard bactericides are not effective enough if weather conditions are favorable for the disease development. Due to lack of resistant cultivars and effective means of protection, researchers have searched for alternative solutions that would provide effective control of this disease. Only integration of different control methods can enable positive effect and achieve an adequate crop protection. Biological methods (use of bacteriophages) and some recent alternative treatments (Systemic Acquired Resistance inducers), have provided the possibility of developing an effective strategy for X. euvesicatoria control.Bakteriozna pegavost paprike i krastavost plodova paradajza koju prouzrokuju bakterije Xanthomonas kompleksa, spada u red rasprostranjenih i ekonomski veoma značajnih bolesti paprike i paradajza. Gajenje otpornih genotipova i primena preparata na bazi streptomicina i jedinjenja bakra ne obezbeđuju zadovoljavajući efekat zaštite, usled pojave novih rasa bakterije i razvoja sojeva rezistentnih prema antibioticima i jedinjenjima bakra. Proizvođači paprike i paradajza nemaju adekvatna sredstva za borbu protiv ovog patogena, jer standardni baktericidi često nisu dovoljno efi kasni kada vremenski uslovi pogoduju razvoju bolesti. Usled nedostatka otpornih sorti, kao i efi kasnih sredstava za zaštitu, istraživači pokušavaju da pronađu alternativna rešenja kojima bi se omogućila efi kasna kontrola ove bolesti. Jedino se integracijom pozitivnog efekta različitih metoda može postići odgovarajući efekat zaštite. Biološke metode (primena bakteriofaga) i neke novije alternativne metode (aktivatori sistemične opornosti), ukazuju na mogućnost razvoja efi kasne strategije za suzbijanje X. euvesicatoria

Polyphasic study of phytopathogenic bacterial strains associated with deep bark canker of walnut in Serbia revealed a new species, Brenneria izbisi sp. nov

Serious outbreaks of walnut deep bark canker were observed on young walnut trees (Juglans regia L.) in two localities in the northern part of Serbia during 2020. From the symptomatic walnut tissues, two types of bacterial colonies were isolated, predominantly, light cream, circular and smooth colonies, as well as small, yellowish, mucoid and convex ones. PCR analysis and phenotypic assays suggested that the former group belongs to Brenneria spp., while the latter isolates were identified as Xanthomonas arboricola pv. juglandis. Within the Brenneria group, two strains were identified as Brenneria nigrifluens, while other 15 strains did not belong to any Brenneria species described so far. Therefore, we selected four representative strains of the unknown Brenneria sp. and subjected them to polyphasic analysis. As expected, in a phylogenetic tree based on partial 16S rDNA sequences, four novel strains grouped with other Brenneria representatives, and showed close phylogenetic relationship to Brenneria salicis. Furthermore, multilocus sequence analysis (MLSA) based on the partial sequences of atpD, gyrB, infB and rpoB housekeeping genes and core-genome phylogeny indicated that the studied strains form a novel and a clearly separate Brenneria lineage. Overall genome relatedness indices showed that they represent a new Brenneria species. The new species can be differentiated from the other Brenneria spp. infecting walnut and closely related B. salicis strains based on phenotypic characteristics, as well. Moreover, the pathogenicity tests on two-year-old walnut plants proved the ability of strains to cause necrosis and longitudinal black lesions and cracks on the trunk and branches of walnut trees. Overall, polyphasic characterization showed that the studied strains isolated from walnut with symptoms of deep bark canker represent a novel species of the genus Brenneria for which the name Brenneria izbisi sp. nov. is proposed. The type strain of B. izbisi is KBI 423T (= CFBP 9035T = LMG 32479T). To facilitate rapid identification of newly described species, a conventional PCR protocol and primers targeting the putative gene hrpP, were developed. Further study should reveal the potential role of each pathogen isolated from symptomatic walnut in disease development as well as possible interaction between them

Isolation and characterization of bacteriophages specific to Acidovorax citrulli

Bacterial fruit blotch and seedling blight, caused by Acidovorax citrulli, is one of the most destructive diseases of melon and watermelon worldwide. Biological approach in the disease control might be a potential solution and substitute for available bactericides of poor efficacy. Therefore, we isolated twelve bacteriophage strains specific to A. citrulli from rhizosphere of watermelon plants showing symptoms of the disease. The strains were characterized based on host range, plaque and virion morphology, thermal point of inactivation, adsorption rate, one step growth curve, and RFLP analysis. All phages lysed 30 out of 32 tested A. citrulli strains isolated in Serbia, and did not lyse other less related species. They produced clear plaques on bacterial lawn of different A. citrulli strains after 24 h of incubation. Examination by transmission electron microscopy of three phage strains indicated that they belong to the order Caudovirales, family Siphoviridae. The thermal inactivation point of phages was 66 or 67 °C. They were sensitive to chloroform, stable in pH 5-9, but inactivated after 5-10 min exposure to UV. RFLP analysis using EcoRI, BsmI and BamHI enzymes did not show genetic differences among the tested phages

Specificity and sensitivity of three pcr-based methods for detection of erwinia amylovora in pure culture and plant material

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 different locations and plant species, with diverse PFGE profiles, representing distant populations of the pathogen. Sensitivity of PCR protocols in pure culture was studied by using nine different concentrations of E. amylovora in sterile ultrapure water as a template in PCR reactions. In order to study inhibitory effect of plant DNA and other inhibitors on sensitivity of the three PCR methods bacterial dilutions were mixed with plant macerate of pear, apple and quince prior to the PCR reaction. In specificity assays, tested PCR protocols were able to detect all E. amylovora strains regardless of the host of the strain, its origin or PFGE group, indicating primer specificity. On the other hand, sensitivity among tested methods varied, depending on bacterial concentration and selected plant material used in the PCR. When working with pure cultures nested PCR showed the greatest sensitivity by detecting 1.9 bacterial cells per PCR reaction, followed by detection limit of 9.5 cells per PCR reaction with conventional PCR and 1.9.105 cells/PCR reaction with chromosomal PCR. In spiked samples plant inhibitors either did not affect or they decreased the sensitivity of the PCR reaction, depending on the protocol and/or type of plant macerate. In our experiments, inhibitors from pear and quince macerates did not affect sensitivity of nested PCR, while apple macerate reduced its sensitivity by a factor of 10. Conventional PCR protocol was able to detect 95 cells/PCR reaction in pear and apple macerate, but only 9.5.103 cells/PCR in quince macerate. Greatest decrease in sensitivity of the PCR method was observed in spiked samples with chromosomal PCR since bacterial DNA was not detected in each of the spiked samples. Our research shows that all three PCR protocols are specific for detection of E. amylovora, but nested PCR proved to be most sensitive when working with pure cultures and plant material

Bakterioze tikava

Production of cucurbits has a long tradition worldwide. Cucumber, watermelon and melon production is very important for many producers in some parts of Serbia. These crops are especially susceptible to phytopathogenic bacteria which can cause substantial losses in years with favorable weather conditions. In this paper major bacterial diseases of cucurbits are described, such as bacterial fruit blotch caused by Acidovorax citrulli, angular leaf spot caused by Pseudomonas syringae pv. lachrymans, bacterial spot caused by Xanthomonas campestris, bacterial wilt caused by Erwinia tracheiphila, cucurbit yellow wine disease caused by Serratia marcescens, bacterial leaf spot, caused by Pseudomonas syringae pv. syringae, inducing bacterial soft rot caused by Pectobacterium species.Biljke familije Cucurbitaceae imaju dugu tradiciju proizvodnje širom sveta. U pojedinim krajevima Srbije, naročito severnim, proizvodnja krastavca, lubenice i dinje predstavlja primarno zanimanje mnogih poljoprivrednih gazdinstava. Pojava bakterioza u godinama sa uslovima koji pogoduju nastanku infekcije, može značajno ugroziti proizvodnju ovih biljaka. U ovom radu predstavljena su najznačajnija bakteriozna oboljenja biljaka familije Cucurbitaceae, među kojima su: bakteriozna mrljavost plodova lubenice, čiji je prouzrokovač Acidovorax citrulli, uglasta pegavost lišća krastavca, prouzrokovana bakterijom Pseudomonas syringae pv. lachrymans; bakteriozna uvelost krastavca prouzrokovana vrstom Erwinia tracheiphila; bakteriozna pegavost koju prouzrokuje Xanthomonas cucurbitae; potom žutilo vreža, čiji je prouzrokovač Serratia marcescens; zatim bakteriozna lisna pegavost prouzrokovana Pseudomonas syringae pv. syringae; kao i bakteriozna vlažna trulež prouzrokovana vrstama roda Pectobacterium