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Results for “fire blight”

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3 recordsLinked to original sources
PubMed2026

Marker-assisted screening of resistance to fire blight, powdery mildew, and apple scab in local apple varieties from Uzbekistan.

Apple (Malus domestica Borkh.) is one of the most economically important fruit crops worldwide; however, its production is severely constrained by major diseases, including fire blight, powdery mildew, and apple scab. Breeding disease-resistant cultivars represents a sustainable alternative to chemical control, particularly through the effective utilization of local germplasm resources from Central Asia. This study aimed to evaluate the presence and distribution of resistance-associated alleles in local apple varieties from Uzbekistan using polymorphic DNA markers. A collection of local apple accessions was screened to identify markers linked to resistance against fire blight, powdery mildew, and apple scab. The analysis revealed substantial genetic variation in resistance gene combinations among the studied varieties. The fire blight-associated marker AE10-375 was detected in 79.8% of the accessions. For powdery mildew resistance, 75.2% of the varieties carried resistance alleles corresponding to both Pl1 and Pl2 genes. Screening for apple scab resistance demonstrated that Vfa2, Vfa1, and Rvi6 were the most prevalent genes, with Vfa2 detected in 95.4% of the accessions. Regional analysis indicated that accessions from Karakalpakstan exhibited the highest proportion of genotypes harboring markers associated with resistance to multiple diseases. Six local varieties-Atlas olma, Turkish, Xuboni, Krasniy jeleznyak, Shoyi olma, and Besh barmoq-were identified as carrying resistance-associated markers for all three diseases. These findings demonstrate that local apple germplasm from Uzbekistan represents a valuable genetic resource for resistance to economically important diseases. The identified genotypes provide promising donor material for breeding programs aimed at developing cultivars with durable, broad-spectrum resistance while reducing reliance on chemical control strategies.

Malus↗
PubMed1975

Partial purification and properties of a beta-glucosidase from Erwinia herbicola Y46.

A constitutive beta-glucosidase of Erwinia herbicola Y46 was studied as a prerequisite to an assessment of its significance in the release of bacteriotoxic aglycones from plant beta-glucosides, and the possible effects of the aglycones on the course of such plant diseases as "fire-blight". The enzyme was purified 86.5-fold from crude extracts of cells grown on yeast beef broth. Ammonium sulfate precipitation, DEAE-cellulose fractionation, and gel filtration through Sephadex G-100 resulted in a preparation having one peak of activity on isoelectrofocussing, on gel filtration through Sephadex G-200, and on polyacrylamide gel electrophoresis. The latter techniques demonstrated, in addition to the major protein band associated with activity, a single minor impurity. The enzyme was active against p-nitrophenyl-beta-glucoside (p-NPG) and phloridzin, but showed only very slight activity against salicin and arbutin, and no detectable activity against beta-methyl-D-glucoside, cellobiose, lactose, and esculin. The production of beta-glucosidase was maximum at the late log phase of growth on yeast beef broth medium and declined somewhat thereafter. The incorporation of inducers (carbohydrates) in defined basal medium resulted in only small variations in specific activity in the resulting cells; The activity (p-NPG substrate) was not inhibited by D-glucose, phloretin, esculin, salicin, arbutin, lactose, or cellobiose, but was slightly inhibited by 1.0 mM phloridzin. Slight inhibition was observed in the presence of sulfhydryl reagents (iodoacetamide, p-chloromercuribenzoate), but sodium azide, ethylene-diaminetetraacetic acid, Cu2+, and Zn2+ ions produced no effect. The activity was stable, in both crude and purified preparations, over the pH ranges 6.0-7.5 (100% activity) and 4.5-greater than 8.5 (50% activity). The enzyme retained 80% activity after 30 min at 50 degrees C, but only 25% after 30 min at 60 degrees C. The enzyme had a mean K-m value (phloridzin) of 1.35 times 10-4 M, an isoelectric point of 4.75, a molecular weight, determined by Sephadex G-200 gel filtration, of about 122 000, and an optimum pH for activity of 6.5-7.0.

Ammonium Sulfate↗