scholarly journals Rizobactérias no controle de Sclerotinia sclerotiorum, e efeitos no desenvolvimento vegetativo de plântulas de soja

2020 ◽  
Vol 16 (4) ◽  
pp. 110-120
Author(s):  
Renata Silva Canuto de Pinho ◽  
Bruna Canabarro Pozzebon ◽  
Ketlen Raisa Rey Rodrigues ◽  
Renata Bolacel Arns ◽  
Cezario Almeida Alves ◽  
...  

Sclerotinia sclerotiorumis one of the main pathogens of soybean crop, reducing crop yield potential and causing losses of up to 37%. Because it is a soil inhabitant, its management is difficult. However, the adoption of alternative methods, such as the use of antagonists, may help reduce the pathogen inoculum. Thus, the objective of this work was to select native soybean rhizobacteria and to verify the potential of in vitroantagonism against Sclerotinia sclerotiorum, as well as the effect of these isolates on the germination and vegetative developmentof soybean seedlings. For this, tests of inhibition and mycelial growth rate index, production of volatile compounds, production of rhizobacterial metabolites and vegetative development of soybean seedlings were conducted.With respect to antagonism, I1, U4, M6, M8 and U13 isolates were the most effective. For the production of volatile compounds by the overlapping plate method, isolates M8, M10, M9, I1, M6 and U4 had the largest reductions in pathogen mycelial growth. For the ability of isolates to produce water-soluble metabolites in culture medium, it was found that isolates I1, M3, M6 and U13 were the most effective. For the vegetative development of soybean seedlings, except for the root length, in which the isolates M8, I14, M9, I1, M6 and M10 provided the largest increases in root size, the other variables did not show significant increases when compared with the witness.In general, isolates M8, M10, M9, I1, M6 and U4 are effective in inhibiting mycelial growth of Sclerotinia sclerotiorum, produce volatile organic compounds that help control the pathogen, however, they do not show significant increases in the vegetative development of soybean seedlings.

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1364-1370 ◽  
Author(s):  
Feng Zhou ◽  
Hong-Jie Liang ◽  
Ya-Li Di ◽  
Hong You ◽  
Fu-Xing Zhu

Growth and virulence stimulations of sublethal doses of fungicides on plant-pathogenic fungi and oomycetes have been reported and the stimulatory effects are potentially relevant to plant disease management. Sclerotinia sclerotiorum is one of the most devastating and economically important necrotrophic fungal phytopathogens, capable of infecting more than 400 species of plants worldwide. In order to study stimulatory effects of sublethal doses of fungicides on S. sclerotiorum, 55 dimethachlon-sensitive isolates and 3 dimethachlon-resistant isolates of S. sclerotiorum were assayed to determine effects of sublethal doses of dimethachlon on mycelial growth rate on potato dextrose agar (PDA) media and virulence on oilseed rape plants. Results showed that all 3 dimethachlon-resistant isolates and 13 of the 55 sensitive isolates exhibited stimulatory responses to sublethal doses of dimethachlon. Dimethachlon-resistant isolates grew significantly (P < 0.05) faster on PDA media amended with dimethachlon at 0.5 to 4 μg/ml than on fungicide-free PDA media. As for virulence on detached leaves of oilseed rape plants, lesion diameters of dimethachlon-resistant isolates after growth on PDA media amended with dimethachlon at 0.5 to 2 μg/ml were significantly larger (P < 0.05) than the control. The maximum stimulatory effects were 42.40 to 59.80%. In pot experiments, for both dimethachlon-sensitive and -resistant isolates, significant (P < 0.05) virulence stimulations were observed after spraying with dimethachlon at a concentration of 2 μg/ml. After growing on dimethachlon-amended PDA media, H2O2 sensitivity of S. sclerotiorum decreased significantly (P < 0.05) compared with the nonamended PDA control.


Author(s):  
Alena V. Kulik ◽  
Margarita A. Shukshina ◽  
Anatoliy N. Evtushenkov

In the presence work, mycelial growth, sclerotia formation, polygalacturonase, a-amylase and cellulase activities of a Belarusian fungal isolate Sclerotinia sclerotiorum KK-1 collected from infected сarrot (Daucus carota subsp. sativus) were analyzed. It was established that polygalacturonase was induced by pectin and subject to catabolite repression by glucose. The ability of the isolate to produce oxalic acid, an important factor of pathogenesis, was observed throughout fungus incubation on PDA medium amended with bromophenol blue. Glyphosate (commercial counterpart «Tornado») starting from its level in the medium of 200 mg/L caused a significant inhibition of mycelial growth and sclerotia formation. It was observed that a-amylase and cellulase activities were inhibited by glyphosate unlike polygalacturonase activity.


Author(s):  
О. Sherstoboeva ◽  
А. Krzyhanivsky ◽  
А. Bunas

Antagonistic microorganisms, producing bactericidal and fungicidal substances, spread in space and occupy various ecological niches. Antagonistic action of microorganisms can be combined with a number of other properties that can be used by humans for their own purposes. Microorganisms — agents of biological products often have a multifunctional effect on the components of the agroecosystem, which under the influence of various environmental factors could have positive and negative consequences. The aim of the study was to study the effect of new highly active entomopathogenic strains of Bacillus thuringiensis on non-target objects — components of the biocenosis of the apple orchard. When developing technologies for biocontrol of the number of apple trees pests using B. thuringiensis revealed an additional positive protective effect — reducing the number of pathogens of fungal diseases on the leaf surface. Treatment of apple leaves with a liquid culture of strain B. thuringiensis 0376 after 72 hours of application reduced the number of scab of Fusicladium dendriticum by 7 times, and the pathogen of monolisis of Monilia fructigena — 9 times. Strain B. thuringiensis 0371 showed the highest level of antagonism, because in vitro completely inhibited the growth and development of micromycetes on the surface of the nutrient medium. On the leaf surface, the application of culture strain 0371 reduced the number of Fusicladium dendriticum by 92%, and Monilia fructigena — by 86% after 72 hours of treatment. In a field experiment when treating apple trees with a culture of this strain, scab development decreased by 7.1%. Strain B. thuringiensis 787 did not show antagonism against phytopathogenicmicromycetes during co-cultivation on nutrient medium, which may be explained by its inability to produce water-soluble exotoxin, in contrast to strains of B. thuringiensis, which are antagonists of scab and apple monolisis. Strain B. thuringiensis 0371 requires further research and development of its formulations, because it is promising for the creation of a complex biological product with insect-fungicidal properties for use in ecological and agriculture friendly technologies.


2021 ◽  
Vol 874 ◽  
pp. 45-49
Author(s):  
Ihsan Arifin ◽  
Grandprix Thomryes Marth Kadja ◽  
Cynthia L. Radiman

Enhanced Oil Recovery (EOR) is a promising technology for increasing crude oil production, especially from old wells. Polymer flooding is one of the techniques used in EOR in which the water-soluble polymer is added to increase the viscosity of the injected fluid. However, this technique has not been implemented in Indonesia due to the unavailability of locally-synthesized polymers. Therefore, this research aims to synthesize polyacrylamides and their partially-hydrolyzed derivatives and to study the possibility of their utilization for the EOR application. Various polymerization conditions using potassium persulfate (KPS) as initiators have been realized and the resulting polymers were characterized using FTIR spectroscopy and rheology measurement. It was found that higher monomer concentration resulted in higher viscosity-average molecular weight of polyacrylamide. Further study revealed that the hydrolysis of polyacrylamide by alkaline solution significantly increased the viscosity of 1000 ppm solution from 1.5 to 145.40 cP at room temperature, which is comparable to one of the commercial products. These results showed that the simple synthesis and hydrolysis method could be effectively used to produce water-soluble polymers for the EOR application.


Plant Disease ◽  
2019 ◽  
Vol 103 (7) ◽  
pp. 1613-1620 ◽  
Author(s):  
Xue-ping Huang ◽  
Jian Luo ◽  
Yu-fei Song ◽  
Bei-xing Li ◽  
Wei Mu ◽  
...  

Sclerotinia sclerotiorum, which can cause Sclerotinia stem rot, is a prevalent plant pathogen. This study aims to evaluate the application potential of benzovindiflupyr, a new generation of succinate dehydrogenase inhibitor (SDHI), against S. sclerotiorum. In our study, 181 isolates collected from different crops (including eggplant [n = 34], cucumber [n = 27], tomato [n = 29], pepper [n = 35], pumpkin [n = 32], and kidney bean [n = 25]) in China were used to establish baseline sensitivity to benzovindiflupyr. The frequency distribution of the 50% effective concentration (EC50) values of benzovindiflupyr was a unimodal curve, with mean EC50 values of 0.0260 ± 0.011 μg/ml, and no significant differences in mean EC50 existed among the various crops (P > 0.99). Benzovindiflupyr can effectively inhibit mycelial growth, sclerotial production, sclerotial shape, and myceliogenic and carpogenic germination of the sclerotia of S. sclerotiorum. In addition, benzovindiflupyr showed good systemic translocation in eggplant. Using benzovindiflupyr at 100 μg/ml yielded efficacies of 71.3 and 80.5% for transverse activity and cross-layer activity, respectively, which were higher than those of acropetal and basipetal treatments (43.6 and 44.7%, respectively). Greenhouse experiments were then carried out at two experimental sites for verification. Applying benzovindiflupyr at 200 g a.i. ha−1 significantly reduced the disease incidence and severity of Sclerotinia stem rot. Overall, the results demonstrated that benzovindiflupyr is a potential alternative product to control Sclerotinia stem rot.


Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1124
Author(s):  
Dawei Yu ◽  
Fuhui Cui ◽  
Yunxiang Cong ◽  
Chunxi Zhang ◽  
Qinghua Tian ◽  
...  

Metallurgical processing of low-grade manganese ore with high iron content is gaining increasing attention due to the gradual depletion of high-grade Mn ores, amid the difficulties in its efficient extraction for both Mn and Fe values in an environmentally-friendly manner. Attempting to tackle the difficulties, this paper describes an innovative process for selectively chlorinating and reducing the high-Fe manganese ore in a simultaneous manner, aiming to produce water-soluble MnCl2 and metallic Fe. After pre-mixing with carbonaceous reductant, CaCl2 and MgCl2 as the chlorinating agent, the Mn ore was heated at 1000 °C. As much as 89.4% Mn can be chlorinated in its water-soluble form, with dissolution of only 3.0% Fe. The presence of CaCl2 during carbothermic reduction resulted in significant promotion in both the Fe reduction rate and formation of large metallic Fe particles due to the segregation effect, facilitating subsequent separation. Selective Mn chlorination by MgCl2 took place with or without the involvement of SiO2, forming MgSiO4 or MgO, respectively.


2020 ◽  
Vol 10 (24) ◽  
pp. 8928
Author(s):  
Irena Budić-Leto ◽  
Iva Humar ◽  
Jasenka Gajdoš Kljusurić ◽  
Goran Zdunić ◽  
Emil Zlatić

Dehydration or drying of grapes is one of the most important steps in the production of Croatian traditional dessert wine Prošek. The natural sun drying of grapes is the traditionally used method in Prošek production. Alternative methods, such as dehydration under controlled conditions, have been studied as safer and faster methods than the traditional sun drying but without precise knowledge of the effect on volatile compounds. The objective of this work was to study how dehydration of grapes carried out in a greenhouse and an environmentally controlled chamber impacts on the free and glycosidically bound volatile compounds of native grape cv. ‘Maraština’. The 36 volatile compounds were identified and quantified using headspace solid-phase micro extraction coupled with gas chromatography-mass spectrophotometry (HS-SPME-GC/MS). The results showed that the aroma profile of dehydrated grapes was significantly different from that of fresh grapes. Regarding free forms, significant increases in the concentration of 2-methyl-1-propanol, 1-butanol, 2-hexen-1-ol, 1-hexanol, ethyl hexanoate, hexyl acetate, o-cymene, linalool oxide, and terpinen-4-ol and geraniol were found in greenhouse-dried grapes, whereas increases in cis-limonene-epoxide, trans-limonene epoxide, and γ-hexalactone were higher in chamber-dried grapes compared to greenhouse-dried grapes. Glycosidically bound forms of o-cymene, linalool oxide, linalool, and terpinen-4-ol were increased in both types of drying, whereas β-damascenone was increased only in greenhouse-dried grapes.


2002 ◽  
Vol 80 (8) ◽  
pp. 892-898 ◽  
Author(s):  
G Q Li ◽  
H C Huang ◽  
S N Acharya

Assays on mycelial growth and spore germination were carried out to determine the sensitivity of the biocontrol agents Ulocladium atrum and Coniothyrium minitans and the plant pathogen Sclerotinia sclerotiorum to benomyl and vinclozolin. Ulocladium atrum was more tolerant to these fungicides than C. minitans and S. sclerotiorum. The 50% effective concentration (EC50) of U. atrum based on the mycelial growth inhibition was 1467.3 µg active ingredient (a.i.)/mL for benomyl and 12.6 µg a.i./mL for vinclozolin, and the maximum inhibition concentration was higher than 4000 µg a.i./mL for both fungicides. For C. minitans and S. sclerotiorum, however, the EC50 based on mycelial growth inhibition was lower than 1 µg a.i./mL. After incubation for 24 h at 20°C, the germination rate of U. atrum conidia was 90–99% on potato dextrose agar (PDA) amended with benomyl at 100–500 µg a.i./mL or vinclozolin at 10–500 µg a.i./mL. At these concentrations, germ tubes of U. atrum developed into long, branched hyphae in benomyl treatments, but they remained short and clustered in vinclozolin treatments. Pycnidiospores of C. minitans and ascospores of S. sclerotiorum germinated on PDA amended with benomyl at 100–500 µg a.i./mL, but the germ tubes did not grow further. Spore germination of C. minitans and S. sclerotiorum was less than 3.2% on PDA amended with vinclozolin at 10–500 µg a.i./mL after 24 h. This is the first report on the sensitivity of U. atrum and C. minitans to benomyl and vinclozolin. The results suggest that it is possible to control S. sclerotiorum using a combination of U. atrum and benomyl or vinclozolin.Key words: fungicides, mycelial growth, spore germination, integrated pest management.


2018 ◽  
Vol 108 (6) ◽  
pp. 807-816 ◽  
Author(s):  
S. Wang ◽  
Y. Liu ◽  
J.-J. Zhou ◽  
J.-K. Yi ◽  
Y. Pan ◽  
...  

AbstractIt is difficult to control Holotrichia parallela Motschulsky with chemical insecticides due to the larvae's soil-living habit, thus the pest has caused great economic losses in agriculture. In addition, uridine diphosphate-glycosyltransferases (UGTs) catalyze the glycosylation process of a variety of small lipophilic molecules with sugars to produce water-soluble glycosides, and play multiple roles in detoxification, endobiotic modulation, and sequestration in an insect. Some UGTs were found specifically expressed in antennae of Drosophila melanogaster and Spodoptera littoralis, and glucurono-conjugated odorants could not elicit any olfactory signals, suggesting that the UGTs may play roles in odorant inactivation by biotransformation. In the current study, we performed a genome-wide analysis of the candidate UGT family in the dark black chafer, H. parallela. Based on a UGT gene signature and the similarity of these genes to UGT homologs from other organisms, 20 putative H. parallela UGT genes were identified. Bioinformatics analysis was used to predict sequence and structural features of H. parallela UGT proteins, and revealed important domains and residues involved in sugar donor binding and catalysis by comparison with human UGT2B7. Phylogenetic analysis of these 20 UGT protein sequences revealed eight major groups, including both order-specific and conserved groups, which are common to more than one order. Of these 20 UGT genes, HparUGT1265-1, HparUGT3119, and HparUGT8312 were highly (>100-fold change) expressed in antennae, suggesting a possible role in olfactory tissue, and most likely in odorant inactivation and olfactory processing. The remaining UGT genes were expressed in all tissues (head, thorax, abdomen, leg, and wing), indicating that these UGTs likely have different biological functions. This study provides the fundamental basis for determining the function of UGTs in a highly specialized olfactory organ, the H. parallela antenna.


2020 ◽  
Vol 32 (3) ◽  
pp. 634-640
Author(s):  
Yatim Lailun Ni'mah ◽  
Wemma Devega ◽  
Ita Ulfin ◽  
Harmami Harmami

Mixtures comprising water-soluble chitosan (WSC), agar and different concentrations of sodium lauryl sulphate (SLS) were used to synthesize capsule films. The concentration of agar was fixed at 0.02 %, whereas the concentration (v/v) of SLS varied (0, 0.02, 0.04, 0.06 and 0.08 %). Shrimp shell waste was subjected to demineralization, deproteination and deacetylation to obtain chitosan. The chitosan thus obtained was depolymerized to produce water-soluble chitosan (WSC). Fourier-Transform infrared (FTIR) baseline method was used for calculating the degree of deacetylation of chitosan. FTIR spectra of the obtained capsule film exhibited vibrations of its constituent molecules, namely agar, chitosan and SLS. The elasticity of the film matrix increased with SLS concentrations. In swelling tests conducted using water and 0.1 N HCl, the highest swelling values, 123.74 and 235.87 %, respectively were observed in the capsule film containing 0.08 % SLS in the 10th min. The capsule film containing 0.08 % SLS was degraded (broken) in water and 0.1 N HCl in the 10th and 30th min, respectively. The results indicated that a capsule film containing 0.08% SLS was the most eligible film for commercial use.


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