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Differential physiological response of cabbage autochthonous cultivar Futoški to infection with Xanthomonas campestris pv. campestris
No full textAutochthonous cabbage cv. Futoški is known for its specific taste and quality. Its yield may be
affected by plant pathogenic bacterium Xanthomonas campestris pv. campestris (Xcc). The aim of
this work was to examine physiological response of cabbage cv. Futoški to infection with differently
virulent Xcc strains. Pathogenicity of eighteen Xcc strains, isolated from cabbage cv. Futoški
was assessed on cabbage plants under controlled greenhouse conditions. Plants were visually
observed for symptoms development two weeks after inoculation and scored according to the
Horsfall-Barratt scale. Based on the obtained results, Xcc strains were divided into three groups
with different virulence potential, i.e. low (3.15–4.93%), medium (7.20–11.35%), and high (21.30–
36.90%). These groups correspond to plants exhibiting low (L), medium (M) and high (H) disease
intensity, respectively. Physiological and morphological parameters – chlorophyll, epidermal flavonoids,
nitrogen balance index (NBI), leaf fresh and dry weight, as well as leaf photosynthetic
parameters were measured in infected plants. The highest chlorophyll content was detected in
H plants, which was accompanied by increased photosynthetic quantum yield, and NBI was also
elevated by 25% in H plants compared to the L plants. Contrarily, the level of epidermal flavonoids
was 25% lower in H plants compared to L plants. Necrotic-induced leaf chlorophyll reallocation,
and consequently increased photosynthetic efficacy, may be linked to plants survival strategies
under infection and maintaining availability of resources. Defense strategies through activation of
secondary metabolism in most infected plants were not observed, as shown by similar values of
epidermal flavonoids compared to control
Specificity of antioxidative response and growth parameters of basil varieties upon transfer from artificial light to open field
No full textBasil is a common aromatic herbaceous plant broadly used in culinary and nutrition. It belongs
to the Lamiaceae family and contains high levels of biologically active compounds. In this study,
three basil varieties (Ocimum basilicum var. genovese – GB, Ocimum × citriodorum – LB and Ocimum
basilicum var. purpurascens – PB) were grown under control conditions at 600 μmol m-2 s-1 and then
transferred to open field with average midday light intensity of 1000–1200 μmol m-2 s-1, with the
aim to study the induced changes in growth and antioxidative metabolism. A seven-day sunlight
exposure resulted in small changes in leaf area and plant height in GB plants, while LB plants
showed increased leaf area. In PB plants, sunlight decreased height and increased leaf area, as well
as anthocyanin biosynthesis. Also, sunlight led to an accumulation of epidermal flavonoids in LB
and GB by 15–25%, while slightly reduced chlorophyll content was observed only in lemon basil
(LB). In addition, the nitrogen balance index (NBI) was lower in all three varieties under full sunlight,
indicating a shift in resource allocation from primary to secondary metabolism. Furthermore, the
accumulation of reduced ascorbate was determined in all basil varieties, while an increase in total
phenolic content (TPC) and total flavonoid content (TFC) was observed only in GB and PB varieties.
Interestingly, no significant differences in total antioxidative capacity (TAC) between varieties
were observed. Taken together, lemon basil is suggested to be the most adaptable to transfer to
high light at open field
APPLICATION OF MATHEMATICAL DECONVOLUTION ON FTIR SPECTRA FOR DETERMINATION OF PROTEIN STRUCTURE IN TOMATO (Solanum lycopersicum L. ) TREATED WITH TRICHODERMA SPP.
No full textThis study investigates the impact of Trichoderma spp. on the protein structure of tomato (Solanum lycopersicum L.) seeds using FTIR spectroscopy. Tomato seed dormancy, which often leads to germination failure, poses a significant challenge for production. Trichoderma, a beneficial fungus, enhances plant growth, stress resistance, and seed quality. By applying T. harzianum and T. brevicompactum to tomato seeds, we monitored changes in protein content and structure through the Amide I (1600-1700 cm⁻¹) and Amide II (1510-1575 cm⁻¹) regions of the FTIR spectra. Mathematical decomposition of these bands allowed us to differentiate between ordered and disordered protein structures, as well as various secondary structures such as α-helices, β-pleated sheets, and β turns. Our analysis revealed that Trichoderma treatments increased the proportions of α-helices and β-pleated sheets while reducing β turns. Additionally, the treatments led to higher proportions of disordered structures in the proteins. This study demonstrates the efficacy of mathematical decomposition in interpreting spectroscopic results and highlights the potential of Trichoderma spp. to improve tomato seed quality and performance
Đorđe Stanojević and light
No full textU vremenu kada je potvrđena elektromagnetna priroda svetlosti, primenjena spektroskopija i fotografija i započeo zamah u eksploatisanju električne energije, najveći uticaj na životno opredeljenje mladog i talentovanog srpskog studenta izvršile su, u teorijskom i u praktičnom smislu, impresije u vezi sa svetlošću. Stanojević je bio profesionalno zaokupljen kako prirodnim izvorom svetlosti, Suncem, tako i veštačkim izvorom – električnom svetlošću. Od samog početka karijere izlaže o izumima poput fotofona, svetlosnog motora i spektroskopa. Nakon objavljivanja dela iz pozicione astronomije uzeo je učešće u astrofizičkom proučavanju Sunca, dok je kasnije bio posvećen elektrifikaciji srpskih gradova i fotografiji. Uporedo sa izučavanjem Sunca i agitacijom za primenu električnog osvetljenja on podučava o istoriji nauke o svetlosti. U opširnom delu Iz nauke o svetlosti objavljenom 1895. godine sumira znanja o optičkim fenomenima u cilju prosvećivanja naroda zaostalog u pogledu saznanja o svetlosti.In the time when the electromagnetic nature of light was confirmed, spectroscopy and photography were applied in astronomy, and the exploitation of electricity just started, impressions about light made the most significant influence on the life choices of a young and talented Serbian student, both theoretically and practically. Stanojević was professionally occupied with the natural source of light – the Sun – as well as with the artificial source – the electric light. From the very beginning of his career, he wrote on inventions such as the photophone, light motor, and spectroscope. After publishing a work on positional astronomy he participated in astrophysical studies of the Sun, while later was dedicated to the electrification of Serbian cities and photography. Alongside his study of the Sun and his advocacy for the use of electric lighting, he taught about the history of the science of light. In his extensive book "From the Science of Light," published in 1895, he summarized knowledge about optical phenomena with the aim of enlightening people
New allelic variant of Pseudomonas syringae pv. aptata lately isolated from sugar beet in Serbia
No full textBacterial leaf spot of sugar beet (Beta vulgaris L.), caused by plant pathogenic bacterium Pseudomonas syringae pv. aptata has emerged frequently in Serbia over the last decade since its initial report in 2013. Symptoms appear as white to light brown necrotic circular spots or irregular lesions each with dark margins. Cool, humid conditions favour the incidence and severity of the disease. The bacterium P. s. pv. aptata is seedborne, so infected seeds are the main source of dissemination for this pathogen across large geographic distances or for establishing in the new areas. The latest outbreak of bacterial leaf spot in sugar beet (cultivar Viola) in Serbia was recorded in 2023 in the regions of Bačka and Srem. Considering that four allelic variants (I-IV) were described for P. s. pv. aptata isolated in 2013, the aim of this research was to genetically characterize P. s. pv. aptata lately isolated from sugar beet, in order to better understand their evolutionary relationships and clustering pattern among strains originating from Serbia.
This study included four strains of P. s. pv. aptata, coded as Psa1523, Psa2023, Psa3223 and Psa4723, previously characterised and selected by repetitive element palindromic polymerase chain reaction-PCR (rep-PCR) using BOX-, ERIC- and GTG5-PCRs. Their phylogenetic position was determined using multilocus sequence analysis relative to P. s. pv. aptata reference strains (PD193 and PD197) and 25 Serbian strains previously isolated (2013) and characterized (2018). DNA of strains was isolated using cetyltrimethylammonium bromide method. Polymerase chain reaction for the four housekeeping genes (gapA, gltA, gyrB and rpoD) was conducted according to the following protocol: an initial denaturation step at 94 °C for 3 min, followed by 30 cycles of denaturation at 94 °C for 2 min, annealing at 54 °C (gapA), 56 °C (gltA), 62 °C (gyrB), and 63 °C (rpoD) for 1 min, and a 1-min extension at 72 °C followed by a final extension step at 72 °C for 10 min. Amplified products were further sequenced at Macrogen Europe (Amsterdam, the Netherlands). Genetic similarity and evolutionary distance were calculated using the MEGA 7 software program. Phylogeny analyses were generated by the Neighbor-Joining (NJ) method using the Kimura 2-parameter model for distance calculations and 1,000 bootstrap replications. Bacterial strain of Pseudomonos savastanoi MHT1 (CP076652) was used as an out-group for the tree rooting. Analyses were performed with both individual gene sequences and the concatenated set of all sequences.
The NJ phylogenetic trees constructed with individual gene sequences of gapA, gltA and gyrB showed the existence of two allelic variants of which three P. s. pv. aptata strains (Psa1523, Psa2023 and Psa4723) corresponded to previously described allelic variant IV of reference strain PD197 and comparative strains isolated in 2013 (known as the most virulent on sugar beet). A new allelic variant was detected for the strain Psa3223 that singled out into a separate tree branch. Additionally, according to the same three housekeeping genes (gapA, gltA and gyrB), none of tested strains grouped with reference strain PD193. Analysed sequences of rpoD gene for all four tested, as well as comparative and reference P. s. pv. aptata strains, were homogeneous. NJ phylogenetic trees with concatenated sequences divided strains into two allelic variants.
The obtained results provide insights into the existence of still unexplored genetic richness within Pseudomonas syringae species complex, but also P. s. pv. aptata species
In vitro evaluation of Bacillus velezensis isolates for biocontrol activities against fungal pathogens
No full textBiological control is increasingly favored as an alternative to the use of pesticides worldwide due to concerns over human health, environmental impact, and food safety. Bacteria from the genus Bacillus are among the most widely exploited biocontrol agents for control plant pathogens and pests and many researchers have focused on this topic over the last two decades. Recently, several commercial biocontrol products formulated with the biocontrol strains Bacillus amyloliquefaciens and Bacillus subtilis have been developed and introduced to the market. The aim of this work was to determine in vitro potential of Bacillus velezensis isolates against different fungal pathogens, considering that this species is not yet included on the EU list of Approved Active Substances for Plant Protection Products.
Three B. velezensis isolates, P64 (originated from pepper seed, cv. Župska rana), BS1 (originated from stem of vegetable soybean “edamame”) and A3 (originated from soil in Serbia) were tested for their antifungal activity in vitro, through a dual culture plate assay. For isolates identification, 16S rRNA gene fragments were amplified using polymerase chain reaction (PCR) method with universal primer pair P0/P6 and then sequenced. Five fungal pathogens were tested: Botryosphaeria dothidea (originated from olive in Montenegro), Botrytis cinerea andColletotrichum acutatum (originated from strawberries in Montenegro), Phomopsis viticola and Neofusicoccum parvum (originated from grapevine in Montenegro). The mycelium plugs (Ø6 mm) of each fungal pathogen was placed at the center of Petri plates with medium Potato Dextrose Agar. Then, per four droplets (5 µL) of overnight-cultured B. velezensis isolates adjusted to approximately 108 CFU mL−1 were deposited on the 2 cm perimeter around the center. Plates inoculated only with mycelia served as positive controls. Commercial biocontrol product Serenade ASO (Bacillus amyloliquefaciens QST 713) served as standard of comparison. Inoculated Petri plates were kept at temperature 25 °C. Results related to growth of tested fungal pathogens were compared to the growth morphology of the fungal controls, and inhibition rate were calculated using a formula (expressed in mm).
All three B. velezensis isolates were genetically identical based on the alignment of the obtained 16S rRNA sequences in the BioEdit v.7.0 software program (ClustalW Multiple alignment tool). According to the nucleotide BLAST (Basic Local Alignment Search Tool, BLASTn) of the National Center for Biotechnology Information (NCBI), isolates showed the highest percent identity (100%) with B. velezensis strain NPPS4 obtained from banana in India. In vitro assay demonstrated that isolates of all five tested fungal pathogens were susceptible to B. velezensis isolates. Inhibition rate of B. dothidea ranged from 44.0-64.2% for B. velezensis isolates and 64.2% for standard product. Strawberry isolates B. cinerea and C. acutatum were inhibited 60.0-63.3% and 33.3-56.7% by B. velezensis isolates and when standard was used 66.7% and 55%, respectively. In case of grapevine isolates P. viticola and N. parvum inhibition rates by B. velezensis were 27.5-40.0% and 58.9-67.8%, and 40.0% and 62.8% for standard product, respectively.
Obtained results revealed that B. velezensis are the suitable biocontrol agents in control of plant pathogenic fungi, and can be exploited for the future research to serve in sustainable management strategies
A study of the effect of biostimulant on the yield and quality of cucumber (Cucumis sativus)-Abstract
No full textIn today's time, with the aim of reducing chemization and increasing yield, the improvement of
plant production is moving towards the introduction of biostimulants. Many biostimulants help
the plant to withstand the effect of biotic and abiotic stresses, increasing quality and yield, and
stimulating physiological processes in the plant. The purpose of this study, improvement
nutritional conditions of cucumber and production with maximum yield by using biostimulants
so if possible recommend this biostimulants asreplacement of current chemical fertilizers.The
experiment was conducted in 2021.year in a greenhouse as a two-factorial experiment with a
completely randomized block design in four replications on two cucumber varieties. Treatments
included three concentrations of 0 (control), 0.5%, 1%, 1.5% by foliar application in three
phases.The best treatment in this study was the biostimulant at a concentration of 1.5%, which
led to a statistically significant increase in yield. The highest yield in all tested variants was
recorded in the Besta variety (14.64 kg m-2) with nutrition with a biostimulant at a concentration
of 1.5%, which is statistically significantly higher compared to the same variety fed up with a
biostimulant at a concentration of 1% (7.33 kg m-2) and 0.5% (8.13 kg m-2)
A study of the effect of biostimulant on the yield and quality of cucumber (Cucumis sativus)
No full textIn today's time, with the aim of reducing chemization and increasing yield, the improvement
of plant production is moving towards the introduction of biostimulants. Many biostimulants
help the plant to withstand the effect of biotic and abiotic stresses, increasing quality and
yield, and stimulating physiological processes in the plant. The purpose of this study,
improvement nutritional conditions of cucumber and production with maximum yield by
using biostimulants so if possible recommend this biostimulants asreplacement of current
chemical fertilizers.The experiment was conducted in 2021.year in a greenhouse as a two-
factorial experiment with a completely randomized block design in four replications on two
cucumber varieties. Treatments included three concentrations of 0 (control), 0.5%, 1%, 1.5%
by foliar application in three phases.The best treatment in this study was the biostimulant at a
concentration of 1.5%, which led to a statistically significant increase in yield. The highest
yield in all tested variants was recorded in the Besta variety (14.64 kg m-2) with nutrition with
a biostimulant at a concentration of 1.5%, which is statistically significantly higher compared
to the same variety fed up with a biostimulant at a concentration of 1% (7.33 kg m-2) and
0.5% (8.13 kg m-2)
Doping Mn Induced Modification on the Crystal Structure, Morphology and Optical Properties of Mechanically Activated SrTiO3 Powders
No full textMechanically activated strontium titanate (SrTiO3) powders with various manganese dioxide (MnO2) doping levels (1.5, 3 and 6 wt%) were prepared by solid state method. Due to the possibility of manganese ion incorporation in SrTiO3 at Ti4+ and/or Sr2+ sites a detailed analysis of the influence of dopants on the microstructure, morphology and optical properties of perovskite oxide was conducted. The investigation showed that manganese was incorporated into the lattice and surface layers of SrTiO3 particles with the presence of manganese segregation and inhomogeneities. Optical measurements indicated a shift of the absorption edge to higher values of wavelengths where the lowest value of the band gap (3.10 eV) was for the longest activation time (120 min) and the highest weight percentage of dopant (6 wt%). In the case of lower concentration (1.5 wt%), there was a significant relative contribution of the substitution of Sr2+ ions by Mn2+ ions, while the substitution of Ti4+ ions by Mn4+ ions dominated samples with an increased concentration
CHARACTERISTICS OF A MIXED COLONY OF BEE-EATERS, STARLINGS AND SWIFTS WITHIN THE PROTECTED HABITAT “GLINARA”, BELGRADE, SERBIA
No full textWe examined the characteristics of a colony of European Bee-eaters (Merops apiaster), Common Starlings (Sturnus vulgaris), and Common Swifts (Apus apus) in a loess bank located within the Protected habitat “Glinara”, Belgrade, Serbia. Using video observations recorded during the 2023 breeding season, we documented 305 active bee-eater nests, 127 starling nests, and 13 swift nests. Bee-eaters and starlings placed significantly more nests in the top and mid portions of the bank compared to the bottom portion, while swift nests were exclusively recorded in the mid and top portions of the bank