Phloridzin and apple scab

Hunter, L.D.

doi:10.1016/0031-9422(75)85343-x

Cited by 32 publications

(11 citation statements)

References 11 publications

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“…Derivatives of hydroxycinnamic acid, dihydrochalcones, flavonols, flavanols and anthocyanidins were reported in apple leaves with the predominance of dihydrochalcones (including the aglycone phloretin and its glucoside, phloridzin). Implications of flavanol contents and phloridzin/flavanol ratio in apple scab ( Venturia inaequalis ) resistance have been proposed (Picinelli et al 1995, Treutter and Feucht 1990), although controversial results have been published (Hunter 1975, Sierotzki and Gessler 1993).…”

Section: Introductionmentioning

confidence: 99%

Erwinia amylovora modifies phenolic profiles of susceptible and resistant apple through its type III secretion system

Pontais¹,

Treutter

Paulin³

et al. 2007

Physiologia Plantarum

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Fire blight is a disease affecting Maloideae caused by the necrogenic bacterium Erwinia amylovora, which requires the type III protein secretion system (TTSS) for pathogenicity. Profiles of methanol-extractable leaf phenolics of two apple (Malus x domestica) genotypes with contrasting susceptibility to this disease were analyzed by HPLC after infection. Some qualitative differences were recorded between the constitutive compositions of the two genotypes but in both of them dihydrochalcones accounted for more than 90% of total phenolics. Principal component analysis separated leaves inoculated with a virulent wild-type strain from those inoculated with a non-pathogenic TTSS-defective mutant or with water. The changes in levels of the various groups of phenolics in response to the virulent bacterium were similar between the two genotypes, with a significant decrease of dihydrochalcones and a significant increase of hydroxycinnamate derivatives. Differences between genotypes were, however, recorded in amplitude and kinetic of variation in these groups. Occurrence of oxidation and polymerization reactions is proposed, based on the browning process of infected tissues, but whether some by-products act in defense as toxic compounds remain to be tested. Among direct antibacterial constitutive compounds present in apple leaves, the dihydrochalcone phloretin only was found at levels close to lethal concentrations in both genotypes. However, E. amylovora exhibited the ability to stabilize this compound at sublethal levels even in the resistant apple, rejecting the hypothesis of its involvement in the resistance of this genotype.

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Section: Introductionmentioning

confidence: 99%

Erwinia amylovora modifies phenolic profiles of susceptible and resistant apple through its type III secretion system

Pontais¹,

Treutter

Paulin³

et al. 2007

Physiologia Plantarum

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“…Supplementation experiments with the amino acid phenylalanine, which is the precursor of all phenylpropanoids including flavonoids, induced resistance of apple to scab caused by the fungus Venturia inaequalis (Holowczak et al 1962). Hunter (1975) and Noveroske et al (1964) proposed a mechanism via phloretin hydroxylation by phenoloxidase being active against scab. Furthermore, analyses of the phenolic concentrations of young leaves revealed good correlation with high procyanidin levels and scab resistance of the susceptible genotype ‘Golden Delicious’ and inhibition of phenylalanine ammonia lyase (PAL) activity in resistant genotype transiently abolished its resistance (Mayr et al 1997).…”

Section: Introductionmentioning

confidence: 99%

Effects of nitrogen supply on growth, contents of phenolic compounds and pathogen (scab) resistance of apple trees

Leser¹,

Treutter²

2004

Physiologia Plantarum

104

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The effect of long-term N-supply on growth, scab resistance and phenolic compounds in the leaves of two apple cultivars was studied. The different pools of phenylpropanoids (hydroxycinnamic acids, dihydrochalcones) and flavonoids (flavonols, catechins, procyanidins) were quanitfied by HPLC from non-infected and inoculated leaves representing different ontogenetic stages. Scab incidence was also evaluated. Strictly following the carbon-nutrient-balance hypothesis, apple trees responded to high N-supply with increased shoot growth and with a reduced accumulation of total phenolic compounds in their leaves. This was shown for the cultivar 'Golden Delicious', which is susceptible to the scab disease caused by Venturia inaequalis, and for the resistant cultivar 'Rewena'. Whereas high N-fertilization increased the susceptibility of 'Golden Delicious', it did not decrease the resistance of 'Rewena' despite of the pronounced reduction of phenolic concentrations. Thus, a simple C trade off between growth-related metabolism and secondary metabolism cannot solely explain changes in defensive potential.

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“…With respect to the host-parasite interaction between the apple Malus domestica and the scab fungus Venturia inaequalis, phenolic compounds have often been stressed as resistance factors (Kirkham, 1957;Barnes and Williams, 1961;Holowczaket a!., 1962a;Raa, 1968;Oydvinand Richardson, 1987). In the past, no clear conclusion could be drawn from laboratory experiments with most of the phenols known to date from apple tissues, namely the derivatives of phloretin, quercetin and caffeic acid (Holowczak et al, 1962b;Noveroske et al, 1964;Hunter, 1975). New analytical techniques facilitated the detection of novel compounds and their precise quantification by routine analysis (Treutter, 1988).…”

Section: Introductionmentioning

confidence: 99%

Phenolic Compounds of Apple and their Relationship to Scab Resistance

Mayr

Michałek

Treutter

et al. 1997

Journal of Phytopathology

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The contents of 15 different phenolic compounds in apple leaves and fruit skin from various orchards were determined by HPLC. High concentrations of flavan‐3‐ols were found in those orchards which were not infected by Venturia inaequalis. This observation corroborates earlier findings on different cultivars. The hypothesis that these compounds could be involved in the resistance of apple to scab was tested by inhibiting the key enzyme of the phenol biosynthesis, the phenylalanine‐ammonia‐lyase, in young shoots of the resistant genotype ‘Sir Prize'. After inoculation of the inhibitor‐treated leaves, severe symptoms of the disease occurred. The fungal infection was confirmed by histological studies. No flavonal‐accumulation could be observed at the infection site which was the case in the non‐inhibited but inoculated controls.

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Phloridzin and apple scab

Cited by 32 publications

References 11 publications

Erwinia amylovora modifies phenolic profiles of susceptible and resistant apple through its type III secretion system

Erwinia amylovora modifies phenolic profiles of susceptible and resistant apple through its type III secretion system

Effects of nitrogen supply on growth, contents of phenolic compounds and pathogen (scab) resistance of apple trees

Phenolic Compounds of Apple and their Relationship to Scab Resistance

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