Patogenost Fusarum vrsta na soji

The paper describes the symptoms of the Fusarium wilt and necrosis of root and lower stem of soybean, which include leaf chlorosis, wilt of the apical portion of the plant, necrosis of the root and lower stem, and wilting of the whole plant. The pods are often poorly developed. The seeds may be smaller and lighter in the weight and infected, as well. Isolated from diseased soybean plants were the species Fusarium avenaceum, F. equiseti, F. oxysporum and F. poae. Pathogenicity tests under artificial infection conditions showed F. oxysporum (isolate S/1) to be the most pathogenic among of the four investigated species. The other species proved much less pathogenic.Fuzariozna uvelost, nekroza korena i prizemnog dela stabla soje pojedinih godina se javlja i u našoj zemlji u većoj ili manjoj meri. Ovo oboljenje se intenzivnije javlja u godinama sa toplim i suvim letima, pogodnim za razvoj uvelosti soje, prouzrokovane vrstama iz roda Fusarium. Iz uzoraka obolelih biljaka sa simptomima oboljenja su izolovane i determinisane vrste Fusarium avenaceum, F. equiseti, F. oxysporum i F. poae. U ogledima sa veštačkom inokulacijom soje najveću patogenost ispoljavao je izolat S/1 F. oxysporum. F. oxysporum (S/1) je značajno smanjio klijavost i nicanje biljaka soje, a povećao broj trulih zrna. Ostale vrste ispoljile su znatno slabiju patogenost. Problemu fuzariozne uvelosti, nekroze korena i prizemnog dela stabla soje trebalo bi posvetiti veću pažnju zbog mogućnosti uvećanja značaja ovog oboljenja usled sve češće pojave toplih i suvih leta, povoljnih za razvoj bolesti

Effects of chemical treatments on infestation of Alternaria spp. and Fusarium spp. in correlation with technological wheat quality

In this study, the time of infestation by fungi from genus Alternaria spp. and Fusarium spp. was investigated in different stages of wheat maturity (milk, waxy, and technological maturity); the effects of different fungicides on the yield, technological properties, and content of mycotoxin DON were studied also. The results showed that Alternaria spp. attacked spike and kernel in f lowering and end-f lowering stage, as it was already known for Fusarium species. Fungicide treatment increases the yield up to 20%, test weight by 3.7%, and thousand-kernel weight up to 19.1%. High content of mycotoxin DON, above tolerable limits, was detected only in the treatment with fungicide Caramba and in untreated control

Procena protokola za brzu izolaciju DNK iz Cercospora beticola Sacc.

The most fungal DNA isolation protocols are designed to obtain high amounts of very pure DNA, requiring large fungal cultures and extraction procedures with many purification steps. Since the PCR does not require high purity DNA, the aim of this investigation was to evaluate three fast and simple fungal DNA isolation protocols for further use in Cercospora PCR based research. The purity and quantity of isolated DNAs were determined spectrophotometrically, electrophoretically and by PCR reaction with universal primers. The amounts of DNA evaluated on agarose gels, isolated by protocols A and C, did not correspond to the spectrophotometrical values, probably due to RNA impurities. In samples isolated by protocol B these impurities were not detected and the DNA concentrations were more similar. Neither protocol eliminated impurities such as carbohydrates and phenol. The average DNA yield of protocol A was 1.04 μg/μl, protocol B 0.88 μg/μl, and protocol C 0.55 μg/μl. The DNA quality most suitable for PCR analysis was obtained by protocol A, where amplification product with universal primers was detected in all DNA samples. The amplification product was detected in 87% of samples isolated by protocol C and in only 60% of samples isolated by protocol B. Although DNA obtained by protocol A had the highest yield and best quality, the isolation protocol C should be also recommended, for it does not require phenol, chlorophorm or liquid nitrogen.Sa ciljem uspostavljanja odgovarajućeg protokola izolacije DNK zaprimenu u istraživanjima zasnovanim na PCR analizi, u radu su ispitana tri jednostavna i brza metoda za DNK izolaciju iz Cercospora beticola Sacc. Čistoća i količina izolovane DNK je određena spektrofotometrijski, elektroforetski i PCR reakcijom sa univerzalnim prajmerima. Količina DNK procenjena na agaroznom gelu, koja je izolovana pomoću protokola A i C nije odgovarala spektrofotometrijskim vrednostima, verovatno usled prisustva RNK nečistoća. U uzorcima izolovanim pomoću protokola B ove nečistoće nisu detektovane, pa su DNK koncentracije bile podudarne. Ni u jednom protokolu nisu eliminisane nečistoće, kao što su ugljeni hidrati i fenoli. PCR amplifikacija je uočena kod svih DNK uzoraka izolovanih protokolom A, kod 60% uzoraka izolovanih protokolom B i kod 87% uzoraka izolovanih protokolom C. Iako je protokol za izolaciju A dao najbolje rezultate, protokol C se takođe može preporučiti, jer ne zahteva upotrebu fenola, hloroforma i tečnog azota

Primena tečne hromatografije sa DAD detektorom za određivanje ostataka acetamiprida i 6-hlornikotinske kiseline u uzorcima trešanja

A rapid and simple method for simultaneous determination of acetamiprid and its metabolite 6-chloronicotinic acid in sweet cherry samples has been developed. This residue analysis method is based on the reversed phase separation on C18 column with gradient elution. Analytes' determination and quantification were performed by high performance liquid chromatography (HPLC) with diode-array detector and chromatograms were extracted at 230 nm. Extraction efficiency experiments demonstrated the ability of this method to extract neonicotinoids from sweet cherry samples. These insecticides were extracted with a mixture of acetonitril/0.1N ammonium-chloride (8/2, v/v). The average recoveries of acetamiprid and 6-chlornicotinic acid from sweet cherry samples were in the range of 95-101% and 73-83%, respectively, with the associated relative standard deviations (RSDs) lt 5%. Expanded measurement uncertainties for the analyzed compounds were 2.7 and 3.01%. The limit of quantification (LOQ) was 10 μg/kg and 30 μg/kg for acetamiprid and 6-chloronicotinic acid, respectively. Thus, the developed HPLC/DAD method can be considered a useful tool for sensitive and rapid determination of acetamiprid and 6-chloronicotinic acid. Hence, the method may find further application in the analysis of real sweet cherry samples contaminated with these insecticides at a ppb level.U radu je predstavljena jednostavna metoda za određivanje acetamiprida i njegovog metabolita, 6-hlornikotinske kiseline, u uzorcima trešanja. Metoda je bazirana na primeni reverzno-faznog razdvajanja na C18 koloni primenom gradijentnog eluiranja. Određivanje i kvantifikacija analita je vršena tečnom hromatografijom (HPLC) sa DAD detektorom, pri čemu je korišćena talasna dužina od 230 nm. Tačnost metode je ocenjena procenom merne nesigurnosti. Ekstrakcija acetamiprida i 6-hlornikotinske kiseline iz uzoraka trešanja je vršena smešom acetonitril/amonijum-hlorid (0,1N) u odnosu 80:20 (v/v). Sva merenja su vršena u tri ponavljanja, pri čemu su dobijeni prinosi određivanja acetamiprida i 6-hlornikotinske kiseline u rasponima 95-101% i 73-83%, respektivno. Relativne standardne devijacije (RSD) merenja su u svim slučajevima bile ispod 5%. Limiti kvantifikacije za acetamiprid i 6-HNK iznosili su 10 i 30 μg/kg, respektivno. Kombinovana merna nesigurnost rezultata analize acetamiprida i njegovog metabolita procenjena je na 1,35, odnosno 1,50%, a proširena na 2,7 i 3,01%, upotrebom faktora pokrivanja (k=2) koji odgovara nivou poverenja od 95%, za normalnu raspodelu. Nakon validacije i procene merne neizvesnosti dobijeni rezultati pokazuju da se razvijena HPLC/DAD metoda može primeniti za određivanje sadržaja acetamiprida i 6-hlornikotinske kiseline u uzorcima trešanja i relevantnim matriksima kontaminiranim ovim jedinjenjima

Genetic diversity of pseudomonas syringae pv. Syringae isolated from sweet cherry in southern and northern regions in Serbia

Bacterial canker and leaf spot caused by plant pathogenic bacterium Pseudomonas is among the most destructive cherry diseases worldwide. Nowadays in Serbia, sweet cherry production significantly increased and the new plantations, mainly grown from imported planting material are being raised every year. During spring, 2018 and 2019, occurrence of bacterial canker and leaf spot symptoms was observed on a newly planted sweet cherry plantations in two localities, Zitorada (Southern region) and Karavukovo (Northern region-Vojvodina). Typical P. syringae colonies were isolated on Nutrient Sucrose Agar supplemented with 5% sucrose (NSA). A total of fifteen isolates were selected and identified. Results of the LOPAT test (+---+) determined them to belong to fluorescent Pseudomonas Group Ia, while results of G(+)A(+)T(-)Ta(-) tests indicate presence of Pseudomonas syringae pv. syringae. Pathogenicity was confirmed on immature sweet and sour cherry fruitlets by forming of black, sunken lesions for all tested isolates. Genes syrB and syrD were successfully detected in all tested isolates. DNA sequencing using gapA, gltA, gyrB and rpoD housekeeping genes determined tested isolates to belong to P. s. pv. syringae using the National Center for Biotechnology Information (NCBI) nucleotide BLAST. The Serbian isolates shared 99.47% to 100% (Zitorada) and 99.38% to 100% (Karavukovo) identity with bacterium P. s. pv. syringae. Phylogenetic analysis grouped isolates from Zitorada in one tree cluster, separate from the Karavukovo isolates,indicating presence of two genetically diverse groups of causal pathogen P. s. pv. syringae, obtained from two geographically distinct localities in Serbia. Phylogeographic analysis grouped isolates from Zitorada in multilocus haplotype coded as REz and isolates originated from Karavukovo in multilocus haplotype coded as REk. Considering that during last few years P. syringae continuously occurs mainly in young sweet cherry plantations, where imported material is used for raising, health status check is recommended to be included as obligatory measure when nursery material is used from import

Metode dijagnostike virusa kržljavosti šljive

Plant diseases caused by phytopathogenic viruses represent a group of diseases (virosis) that can cause high economic losses and become a limiting factor in achieving full fertility and a quality yield. The transmitting ways of the viruses are multiple, and the main way to combat these diseases is the production, or use of healthy, virus-free seed and planting material. Since viruses cause the most significant damage on woody plants, fruits and vines, it is important to carry out a plant virus screening test in order to avoid multiple harmful effects in both aspects, the material and in the aspect of the time it takes for these plant species to grow and achieve a full fertility. One of the most common viruses infecting stone fruit species and causing significant economic damages is the Prune dwarf virus (PDV). Given the general presence in the world and high destructive potential of PDV, its diagnostic and identification methods are described in detail in this study.Bolesti gajenih biljaka čiji su prouzrokovači fitopatogeni virusi, predstavljaju grupu bolesti (viroze), koje mogu prouzrokovati značajne ekonomske gubitke i postati ograničavajući faktor u postizanju pune rodnosti i dobijanja kvalitetnog prinosa. Načini prenošenja virusa su višestruki, a glavni način borbe protiv ovih oboljenja je proizvodnja, odnosno korišćenje zdravog semena i bezvirusnog sadnog materijala. Budući da virusi najveće štete ispoljavaju na drvenastim biljkama, voću i vinovoj lozi, važno je sprovesti proveru sadnog materijala na prisustvo virusa, kako ne bi došlo do višestrukih štetnih efekata, kako u materijalnom aspektu tako i u aspektu vremena koje je potrebno da ove biljne vrste stasaju i postignu punu rodnost. Jedan od najčešćih virusa koji inficira koštičave voćne vrste i na njima pričinjava značajne ekonomske štete je virus kržljavosti šljive (PDV). Imajući u vidu opšte prisustvo u svetu i visok destruktivni potencijal PDV virusa, metode njegove dijagnostike i identifikacije detaljno su opisane u ovom radu

УТИЦАЈ Bacillus spp. НА ПАТОГЕНА ПШЕНИЦЕ Alternaria alternata И in vitro УСЛОВИМА

Species of the genus Alternaria are significant wheat contaminants during production, transport and storage, requiring biocontrol measures which typically rely on the bacteria from the Bacillus genera. As these are among the most beneficial and exploited biocontrol agents, in this study, the inhibitory activity of indigenous Bacillus spp. was assessed against the Alternaria alternata isolate originating from the wheat seed. Two of the fifteen Bacillus s pp. i ncluded i n t he s tudy s howed t he i nhibitory effect. Specifically, 25.0−55.0% inhibition of A. alternata growth was achieved when the isolate coded as NB11 was applied in 106−109 cells mL-1 concentrations. On the other hand, when applied in 107−109 cells mL-1 concentrations, the isolate coded as NB16 inhibited A. alternata growth by 35.2−51.1%, but was ineffective at lower concentrations. Thus, these in vitro assays indicate that both Bacillus spp. (NB11 and NB16) isolated from the wheat rhizosphere can be applied in practice in the control of A. alternata

Etiology of bacterial diseases of young walnut trees in Serbia

In the summer and autumn of 2019-2020, young walnut orchards were monitored for the presence of bacterial diseases. Diseased walnut samples comprising trunks and branches with symptoms of vertical oozing canker (VOC), walnut bacterial blight (WBB) and superficial bark necrosis were collected from eight locations in Serbia. Based on phenotypic features, pathogenicity, and molecular assays using PCR with specific primers, 49 isolates obtained from samples showing VOC and WBB symptoms were identified as Xanthomonas arboricola pv. juglandis, while further two isolates obtained from bark necrosis were identified as Brenneria rubrifaciens. One tested X. a. pv. juglandis isolate obtained from a VOC sample produced deep cankers in the bark of inoculated trunks of young walnut trees (cultivars Chandler, Franquette and Šejnovo). Therefore, this is the first report of an association between X. a. pv. juglandis and VOC symptom in Serbia. Considering that X. a. pv. juglandis significantly endangers walnut production, the presence of this pathogen in walnut transplant imports needs to be assessed by an authorised laboratory. Furthermore, as this is also the first report of B. rubrifaciens on walnut trees in Serbia, it is noteworthy that this pathogen is not particularly harmful to young walnut trees

Differentiation between aspergillus flavus and aspergillus parasiticus isolates originated from wheat

The species of the genus Aspergillus, A. flavus and A. parasiticus, are the most aflatoxin-producing fungi. All previous studies carried out under the production conditions of Serbia showed no presence of A. parasiticus on wheat kernel. On the basis of changes in climatic factors, such as occurrence of high temperatures and prolonged droughts, which favour increased frequency of Aspergillus spp., we assumed that this pathogen can also be present in Serbia. The significance of direct losses as a consequence of wheat kernel infection, as well as potential contamination with aflatoxins, have pointed out to the need to determine the presence of toxigenic potential of A. flavus and A. parasiticus isolates originating from Serbia. For that purpose, wheat kernel samples were collected in nine locations. According to morphological, toxicological and molecular traits of isolated fungi, the presence of A. flavus and A. parasiticus was confirmed. This is the first time that A. parasiticus was identified on wheat under climatic conditions in Serbia. This study indicates that these pathogens may be a potential danger in wheat production in the region of Serbia. This danger will be much more certain if global climatic changes continue as they will provide more intensive development of these pathogens