THE ROLE OF PHLORIDZIN IN THE HOST-PARASITE PHYSIOLOGY OF THE APPLE SCAB DISEASE

1961 ◽  
Vol 7 (4) ◽  
pp. 525-534 ◽  
Author(s):  
E. H. Barnes ◽  
E. B. Williams
Keyword(s):  
Phenolic Compounds ◽  
Benzoic Acid ◽  
Protocatechuic Acid ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Breakdown Product ◽  
Stimulatory Action ◽  
Apple Leaves ◽  
Host Parasite

A stimulating substance in apple leaves which enhances the growth of Venturia inaequalis (Cke.) Wint. was identified as phloridzin. The metabolism of this compound to phloretin, phloroglucinol, p-hydroxyphenyl propionic acid, p-hydrox-y benzoic acid, and protocatechuic acid is hypothesized on the presence of phloretin and phloroglucinol in the culture filtrates of V. inaequalis when it is grown in the presence of phloridzin. The only breakdown product which stimulated the parasite was p-hydroxyphenylpropionic acid and it is concluded that its utilization by V. inaequalis may be the basis for the stimulatory action of phloridzin.The effect of these compounds and m-inositol on the growth and sporulation of V. inaequalis was studied. All of the compounds induced resistant reactions in the 384-1 selection but not in the Geneva variety. This may represent a specificity of the host to the action of these chemicals, indicating that they are correlated with the specificity of the host to races of V. inaequalis. Preliminary studies on the effects of these compounds on the metabolism of the host indicated that new phenolic compounds are produced.

scholarly journals Role of urea in the reduction of apple primary infections by Venturia inaequalis (Cooke) Aderh

2013 ◽  
Vol 55 (1) ◽  
pp. 225-231
Author(s):  
Beata Meszka ◽  
Anna Bielenin
Keyword(s):  
Chemical Control ◽  
Primary Infection ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Leaf Fall ◽  
Urea Treatment ◽  
Apple Leaves ◽  
Leaf Infection ◽  
Ascospore Production

The effect of pre-leaf fall of 5% urea treatment on primary infection of apple by <i>Venturia inaequalis</i>, the cause of scab, was investigated in commercial apple orchards of McIntosh cv. in different regions of Poland, at Miłobądz, Sinołęka and Dąbrowice. Additionally, the development of pseudothecia and maturation of ascospores were evaluated in the spring on apple leaves of two cultivars (McIntosh and Gloster) treated with 5% solution of urea. Microscopic observations of leaves showed that urea treatment significantly reduced the number of pseudothecia (by ca. 90%) and ascospore production. Low number of ascospores after urea treatment has strongly affected primary infection of apple by the fungus in all tested orchards. Reduction of leaf infection on control trees was usually more than 30%. Also efficacy of chemical control of apple scab was significantly higher on plots treated with urea.

Seasonal changes in phenolic compounds in the leaves of scab-resistant and susceptible apple cultivars

2009 ◽  
Vol 89 (4) ◽  
pp. 745-753 ◽  
Author(s):  
M Mikulic Petkovsek ◽  
F Stampar ◽  
R Veberic
Keyword(s):  
Phenolic Compounds ◽  
Seasonal Changes ◽  
High Performance ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Growing Season ◽  
Total Phenols ◽  
Apple Varieties ◽  
Apple Leaves ◽  
Apple Cultivars

Leaf samples were collected from apple varieties susceptible and resistant to apple scab [Venturia inaequalis (Cke.) Wint.] from June to September for 2 yr between 2005 and 2006. These were analyzed for phenolic compounds, using high-performance liquid chromatography (HPLC). In the apple leaves, the following hydroxycinnamic acids were detected: chlorogenic, caffeic and p-coumaric acids; the following dihydrochalcone: phloridzin, and the following flavonoids: epicatechin, catechin, rutin and quercitrin. The total of phenolic compounds in apple leaves was determined spectrophotometrically, using the Folin-Ciocalteu method. During the growing season, the content of phenolic compounds changed and was related to the physiological stage of the tissue and cultivar used. Each phenolic compound had its own curve of seasonal changes in concentration. In 2005 there was no significant change in total phenols during the growing season. In 2006, their content changed significantly during the growing season; statistically the highest content of total phenols was found in the leaves in August. Total phenols as well as single phenolics were statistically higher in resistant than in susceptible apple varieties for both years.Key words: Malus × domestica Borkh., leaves, phenolic compounds, seasonal changes, Venturia inaequalis (Cke.) Wint., resistance

scholarly journals A New Phytosanitary Method to Reduce the Ascospore Potential of Venturia inaequalis

Plant Disease ◽  
2017 ◽  
Vol 101 (3) ◽  
pp. 414-420 ◽  
Author(s):  
Franziska M. Porsche ◽  
Barbara Pfeiffer ◽  
Andreas Kollar
Keyword(s):  
Leaf Litter ◽  
Yeast Extract ◽  
Untreated Control ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Nutrient Media ◽  
Apple Leaves ◽  
Litter Decay ◽  
Ascospore Discharge ◽  
Infection Pressure

Ascospores of Venturia inaequalis, released from pseudothecia in overwintered, infected apple leaves, serve as the primary inoculum for apple scab. In this study, we tested a new sanitation strategy to reduce ascospore inoculum under orchard conditions over three overwintering periods. After leaf fall, nutrient media containing different concentrations of degraded casein or a yeast extract from Saccharomyces cerivisiae were applied to leaf litter infected with apple scab. The application of 30 and 60% yeast extract showed the greatest efficacy, and significantly reduced ascospore discharge by 99% (P < 0.01) in 2013 and 2014. The efficacy of the treatments did not differ from treatment with 5% urea (P > 0.05). Leaf litter decay was accelerated in the plots treated with yeast extract compared with untreated control plots. Moreover, apple leaves treated with yeast extract had completely decayed due to earthworm activity before ascospore maturity. In comparison, up to 26% of the leaves in untreated control plots had not decayed. These results suggest that the treatment of leaf litter with yeast extract can almost completely eliminate apple scab inoculum in the course of the whole primary season. These sanitation practices may be beneficial for both organic and conventional cultivation. The reduced infection pressure may allow growers the usage of fungicides with lower efficacy or to reduce the number of applications needed to manage apple scab in spring.

Evidence for the role of antibiosis in the antagonism of Chaetomium globosum to the apple scab pathogen, Venturia inaequalis

1984 ◽  
Vol 62 (9) ◽  
pp. 1819-1823 ◽  
Author(s):  
Daniel Cullen ◽  
John H. Andrews
Keyword(s):  
Antibiotic Production ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Chaetomium Globosum ◽  
Growth Chamber ◽  
Fungistatic Activity ◽  
Chamber Studies ◽  
Growth Chamber Studies ◽  
Layer Chromatography

Ascospore suspensions and culture extracts of Chaetomium globosum Kunze: Fr. reduced infection of apple seedlings by Venturia inaequalis (Cke.) Wint. (anamorph, Spilocaea pomi Fr.) in growth-chamber studies. An agar diffusion assay was developed to assess the relative fungistatic activity of culture extracts of C. globosum. No differences were observed in the sensitivity of 37 V. inaequalis strains to C. globosum extracts. Seven strains of C. globosum from diverse habitats were evaluated for antibiotic production in culture. Significant differences in antibiotic production between strains were observed, and antibiotic levels were positively correlated with antagonism to V. inaequalis on seedlings in growth-chamber studies. The antibiotic chetomin was tentatively identified in culture extracts by thin-layer chromatography and ultraviolet absorbance. The selection of high antibiotic producing strains of C. globosum may significantly improve antagonistic performance in the field.

Phenolic compounds in apple leaves after infection with apple scab

2011 ◽  
Vol 55 (4) ◽  
Author(s):  
M. Petkovsek ◽  
A. Slatnar ◽  
F. Stampar ◽  
R. Veberic
Keyword(s):  
Phenolic Compounds ◽  
Apple Scab ◽  
Apple Leaves

ESTIMATION OF BIOACTIVE PHENOLIC COMPOUNDS OF ABIES PINDROW AERIAL PARTS USING TLC DENSITOMETRY

INDIAN DRUGS ◽  
2017 ◽  
Vol 54 (04) ◽  
pp. 32-37
Author(s):  
D. Kumar ◽  
S. Kumar ◽  
Keyword(s):  
Phenolic Compounds ◽  
Benzoic Acid ◽  
Gallic Acid ◽  
Protocatechuic Acid ◽  
Coumaric Acid ◽  
Aerial Parts ◽  
Ich Guidelines ◽  
Validation Parameters ◽  
Abies Pindrow ◽  
Solvent Systems

The present investigation was undertaken to estimate contents of bioactive phenolic compounds in A. pindrow aerial parts using TLC densitometry. Maltol, p-coumaric acid, p-hydroxy benzoic acid, protocatechuic acid and gallic acid were resolved in TLC of methanol extract of plant using solvent systems – chloroform:methanol (9.7:0.3; scanned at 276 nm), toluene:diethyl ether (1:1; scanned at 320 nm), chloroform:methanol:glacial acetic acid (19:1:1; scanned at 266 nm), chloroform:methanol:formic acid (9:1:1; scanned at 295 nm) and chloroform:methanol:acetonitrile: formic acid (12:3:3:2; scanned at 292), respectively. The developed methods for estimation of phenolic compounds in plant were validated as per ICH guidelines. The contents of maltol, p-coumaric acid, p-hydroxy benzoic acid, protocatechuic acid and gallic acid in plant were found to be 0.10280±0.00002, 0.00860±0.00000, 0.00780±0.00001, 0.10030±0.00003 and 0.06440±0.00002% w/w, respectively. On the basis of validation parameters, the developed TLC densitometric methods for estimation of phenolic compounds in the plant were found to precise, accurate and specific.

scholarly journals Fungal communities isolated from dead apple leaves from orchards in Quebec

2005 ◽  
Vol 77 (3) ◽  
pp. 129-134 ◽  
Author(s):  
J. Bernier ◽  
O. Carisse ◽  
T.C. Paulitz
Keyword(s):  
North America ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Causal Agent ◽  
Biocontrol Agents ◽  
Fungal Communities ◽  
Malus Pumila ◽  
Apple Leaves

Venturia inaequalis, the causal agent of apple scab, overwinters in apple (Malus pumila) leaves on the orchard floor by producing pseudothecia. The objectives of this survey were to make a collection of fungi to be subsequently tested for their potential as psychrophile biocontrol agents against V. inaequalis and to acquire knowledge on the diversity of the microflora of dead apple leaves. Fungi were recovered from dead apple leaves collected in the spring and fall of 1993. A total of 345 isolates from 49 genera were identified. Fifteen gene were not previously recorded as colonizers of apple leaves in North America.

scholarly journals PHENOLIC COMPOUNDS FROM CALLISTEMON CITRINUS LEAVES AND STEMS

2016 ◽  
Vol 54 (2) ◽  
pp. 190 ◽  
Author(s):  
Pham Ngoc Khanh ◽  
Ho Viet Đuc ◽  
Tran Thu Huong ◽  
Vu Thi Ha ◽  
Doan Thi Van ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Benzoic Acid ◽  
Protocatechuic Acid ◽  
2D Nmr ◽  
Chemical Investigation ◽  
Phytochemical Analysis ◽  
Methyl Gallate ◽  
Bioactive Constituents ◽  
Esi Ms ◽  
Benzoic Acid Derivatives

In the search for bioactive constituents from Vietnamese plants,  the leaves and stems of Callistemon citrinus (Curtis) Skeels were selected for chemical investigation. Phytochemical analysis of plant led to the isolation of eight phenolic compounds including two flavonoids (eucalyptine (1) and 8-demethyleucalyptine (2)), two alcohols (blumenol A (3), n-tetratriacontanol (4)), three benzoic acid derivatives (acid gallic (5), methyl gallate (6) protocatechuic acid (7)), one sterol (b-sitosterol (8)), and along with one sesquiterpene (2,6,10-bisabolatriene (9)). The structures of the natural compounds were determined by spectroscopic evidences including 1D- and 2D-NMR and ESI-MS.

Benomyl-marked populations of Chaetomium globosum: survival on apple leaves with and without benomyl and antagonism to the apple scab pathogen, Venturia inaequalis

1985 ◽  
Vol 31 (3) ◽  
pp. 251-255 ◽  
Author(s):  
Daniel Cullen ◽  
John H. Andrews
Keyword(s):  
Resistant Strain ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Chaetomium Globosum ◽  
Wild Type ◽  
Population Densities ◽  
Apple Trees ◽  
Initial Inoculum ◽  
Apple Leaves ◽  
Rate Of Decline

Resistance to the fungicide benomyl (BenR) was induced with N-methyl-N′-nitro-N-nitrosoguanidine in Chaetomium globosum isolated from apple leaves. The population densities of a resistant strain reintroduced to leaves on apple trees in an orchard were determined at 3 h, and 1 and 3 weeks following inoculation. Relative to wild-type parents, BenR populations declined more rapidly on orchard trees, but the rate of decline was reduced by amending initial inoculum with 18.5 ppm benomyl. Survival of BenRC. globosum increased 40–58% relative to BenRC. globosum applied without benomyl. In growth chamber experiments with potted apple seedlings, the BenR strain was as antagonistic as were the wild-type parents to the scab pathogen, Venturia inaequalis. The marked strain alone did not significantly reduce scab infection on saplings in the field; however, when it was applied with benomyl, scab severity was significantly (P = 0.01) less than with benomyl alone.

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