Antibacterial activity of coumarin as an innovative organic control strategy for Xanthomonas euvesicatoria pv. euvesicatoria

Journal of Plant Diseases and Protection - Bacterial spot caused by Xanthomonas euvesicatoria pv. euvesicatoria (Xanteu) is one of the major causes of yield losses in tomato (Lycopersicon...     

Use of random amplified polymorphic DNA (RAPD) to identify races 1, 2, 4 and 8 of Fusarium oxysporum f. sp. dianthi in Italy

The RAPD fingerprinting procedure was used in combination with pathogenicity assays on differential cultivars to characterize a representative collection of 72 Fusarium spp. isolates of different geographic origin collected from diseased carnation. In F. oxysporum f. sp. dianthi, isolates were grouped according to the physiologic race: group 1 included isolates of race 4; group 2 was formed by isolates of race 2 and single representatives of races 5 and 6; group 3 included isolates of races 1 and 8. No correlation was found between RAPD data and geographic origin of the isolates tested: representatives of race 2 isolated in Italy, Israel and Japan had the same amplification profile. Three isolates which showed a low level of pathogenicity on all carnation cultivars tested shared an identical amplification pattern and are probably saprophytic F. oxysporum. Finally, two F. redolens isolates from Japan and seven non-pathogenic isolates of F. proliferatum collected from diseased carnation in Italy, Israel and The Netherlands were clearly distinguishable according to their RAPD fingerprint. The results are discussed in relation to previous studies on the genetic diversity of F. oxysporum f. sp. dianthi and to the development of forma specialis- and pathotype-specific diagnostic tools.     

Anastomosis groups and sensitivity to fungicides of Rhizoctonia solani strains isolated from potato in Russia

Journal of Plant Diseases and Protection - A survey of Rhizoctonia solani isolates from potato tubers and stems grown in European and Far Eastern regions of Russia in 2012–2020 was conducted....     

Multifunctionalised benzoxazinones in the systems Oryza sativa–Echinochloa crus‐galli and Triticum aestivum–Avena fatua as natural‐product‐based herbicide leads

BACKGROUND: Fifteen novel derivatives of D‐DIBOA, including aromatic ring modifications and the addition of side chains in positions C‐2 and N‐4, had previously been synthesised and their phytotoxicity on standard target species (STS) evaluated. This strategy combined steric, electronic, solubility and lipophilicity requirements to achieve the maximum phytotoxic activity. An evaluation of the bioactivity of these compounds on the systems Oryza sativa–Echinochloa crus‐galli and Triticum aestivum–Avena fatua is reported here. RESULTS: All compounds showed inhibition profiles on the two species Echinochloa crus‐galli (L.) Beauv. and Avena fatua L. The most marked effects were caused by 6F‐4Pr‐D‐DIBOA, 6F‐4Val‐D‐DIBOA, 6Cl‐4Pr‐D‐DIBOA and 6Cl‐4Val‐D‐DIBOA. The IC₅₀ values for the systems Echinochloa crus‐galli–Oryza sativa and Avena fatua–Triticum aestivum for all compounds were compared. The compound that showed the greatest selectivity for the system Echinochloa crus‐galli–Oryza sativa was 8Cl‐4Pr‐D‐DIBOA, which was 15 times more selective than the commercial herbicide propanil (Cotanil‐35). With regard to the system Avena fatua–Triticum aestivum, the compounds that showed the highest selectivities were 8Cl‐4Val‐D‐DIBOA and 6F‐4Pr‐D‐DIBOA. The results obtained for 6F‐4Pr‐D‐DIBOA are of great interest because of the high phytotoxicity to Avena fatua (IC₅₀ = 6 µM , r² = 0.9616). CONCLUSION: The in vitro phytotoxicity profiles and selectivities shown by the compounds described here make them candidates for higher‐level studies. 8Cl‐4Pr‐D‐DIBOA for the system Echinochloa crus‐galli‐Oryza sativa and 6F‐4Pr‐D‐DIBOA for Avena fatua‐Triticum aestivum were the most interesting compounds. Copyright © 2010 Society of Chemical Industry     

Regional and temporal differentiation of virulence phenotypes of Puccinia triticina from common wheat in Russia during the period 2001–2018

Leaf rust, caused by the fungus Puccinia triticina, is one of the most damaging rust diseases of wheat in Russia. Populations of P. triticina were monitored in seven regions of Russia from 2001 to 2018, with a total of 5,191 single urediniospore isolates from bread wheat (Triticum aestivum) being analysed. Populations have changed significantly in all regions since 2012, after 2 years of drought (2010–2011). Regional collections of P. triticina were also significantly different between the two periods 2001–2009 and 2012–2018, with changes along two geographic gradients from West Siberia to the north-west and south-west (North Caucasia) of the European part of Russia. All tested isolates were avirulent to resistance gene Lr9 in 2001–2009 but, since 2010, virulence to Lr9 has occurred and annually increased in the Asian part of Russia (Ural and West Siberia) due to deployment of cultivars with the Lr9 gene. Virulence to Lr2a and Lr15 was considerably lower in Dagestan (6%–33%) and all European regions (35%–67%) than in Asian regions (84%–96%). During 2001–2009, virulence on Lr1 was also lower in Dagestan (33%) and the European regions (50%–77%) than in Asia (91%–96%); however, by 2012–2018, nearly all isolates were virulent on Lr1. Remarkable changes were observed in frequencies of P. triticina races defined by their virulence/avirulence to Lr1 and Lr2a genes. We postulate the P. triticina population in Dagestan is specific to that area and pathogen populations in European and Asian parts of Russia are distinct.     

Direct colloid osmometry in healthy New World camelids

Background: Direct colloid osmometry provides an objective assessment of the oncotic effects of crystalloid or colloidal fluid therapy, which is especially useful in monitoring fluid therapy of critically ill camelids due to their tendency toward nonspecific hypoproteinemia with increased risk of developing edema and ascites. Objectives: The aims of this study were to measure colloid osmotic pressure (COP) of alpacas and llamas, determine its correlation with concentrations of total protein (TP) and total solids (TS), as well as both albumin (A) and globulin (G) concentrations in the same model (A+G), and evaluate the effects of sample type and storage conditions on COP. Methods: Blood was collected from clinically healthy alpacas (n=23) and llamas (n=22) into heparin tubes. COP of fresh whole blood (COP_FB) and plasma (COP_FP) was determined using a membrane osmometer. For 20 alpacas, COP of refrigerated whole blood (COP_RB) and frozen plasma (COP_FrP) was also measured. Correlations between COP_FB and TS, TP, and A+G concentrations were assessed by simple and multiple regression analysis to model potential predictors. Results: Median COP_FB from alpacas (24.6 mmHg, range 19.3–28.1) was not significantly different from that of llamas (25.3 mmHg, range 22.5–33.7). Sample type or storage conditions did not affect COP. Measured COP had a strong positive linear correlation with TS, TP, and A+G concentrations in alpacas (r²=.7, .74, and .88, respectively). In llamas, COP correlated best with TS concentration (r²=.59), whereas correlation with TP and A+G concentrations was poor (r²=.19 and .25, respectively). Conclusion: COP can be measured using heparinized whole blood or plasma, either fresh or stored. Direct measurement is recommended whenever quantitative knowledge of COP is required in clinical or research setting. Further studies are needed to verify if the poor association of COP with TP found in this study can be generalized to llamas.