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Showing 4 results for Baghaee-Ravari
Volume 3, Issue 3 (9-2014)
Abstract
Samples of leaf, twig and fruit from ‘Mexican’ lime (Citrus aurantifolia) and grapefruit (Citrus paradisi) with symptoms of bacterial canker were collected from different provinces throughout Iran during spring and summers of 2010 and 2011. Yellow, gram-negative colonies were isolated from infected tissue samples. Results of pathogenicity assays indicated that some isolates incited tissue hyperplasia, hypertrophy and raised callus-like lesions typical of canker in hosts while other isolates stimulated flat necrotic and water-soaked lesions on leaves. Candidate samples of each group were identified according to morphological and physiological characteristics. Detections were also made using specific primers and partial sequencing of 16SrDNA for Pantoea group and gyrB for Xanthomonas group. Results showed that one group was characterized as the typical Xanthomonas citri subsp. citri strain while the other group containing most of the isolates was identified as Pantoea agglomerans. Samplings done frequently in different seasons revealed the presence of high populations of P. agglomerans with bacterial canker, especially in warmer and drier regions. These bacteria were able to incite canker-like symptoms on grapefruit seedlings and could be reisolated after two months.
Volume 13, Issue 3 (12-2024)
Abstract
Among rhizobacteria, plant-beneficial effects of Pseudomonas bacteria are known in agricultural ecosystems. Screening of fluorescent pseudomonad isolates obtained from potato rhizosphere led to selecting five bio-reagents capable of controlling soft rot disease caused by Pectobacterium carotovorum subsp. carotovorum (Pcc) (JX029052) in plate assay, on intact potato tubers and under storage challenges using preventative and curative applications. The biocontrol features related to the tested rhizospheric bacteria were also evaluated. According to phenotypic tests, the representative antagonistic strains belong to the fluorescent pseudomonads group and are placed in the P. protegens cluster based on 16S rRNA gene sequencing. Strains IrPs8 and IrPs18 are potent to produce siderophore, cyanide hydrogen, and protease, form strong biofilm and carry phl, plt and prn genes on their genomes corresponding to 2, 4-diacetylphloroglucinol, pyoluteorin and pyrrolnitrin, respectively. Treated tubers inoculated with IrPs8 and IrPs18 showed a reduction in the soft rot-inducing potency of Pcc by 63.4 and 65.5% in preventative and by 57.8 and 58.3% in curative tests, respectively, under storage conditions that confirmed the in vivo results. This study highlights the potential of rhizospheric P. protegens strains as beneficial bacteria that can be suggested as preservative coatings for potato tubers under storage conditions.
Volume 21, Issue 4 (7-2019)
Abstract
In the current study, the phenotypic and molecular properties of twenty-five strains obtained from cankerous tissues or leaf necrotic lesions of different stone fruits were evaluated in north-east of Iran . All strains studied were identified as Xanthomonas arboricola pv. pruni (Xap) based on phenotypic assays and confirmed by means of specific PCR at species and pathovar levels. All obtained strains were pathogenic under artificial inoculation and exhibited brittle necrotic spots on plum leaves of cultivar Santa Rosa under lab conditions. Then, the pathogenic Xap strains were subjected to molecular assays. In a phylogenetic tree constructed with gyrB sequences, no polymorphism was observed in this gene and Iranian Xap strains were clustered with the reference one in a separate group. The ERIC, BOX and REP primer sets generated reproducible genomic PCR profiles in tested strains and, based on combined data for all primers, a low genetic diversity among Xap strains was revealed. In order to achieve results that are more accurate, application of Xap strains from all geographical regions of Iran will be needed to prove little polymorphism observed in Xap population. The current contribution is the first report of molecular homogeneity of Xap strains that were collected from northeastern Iran.
Volume 25, Issue 6 (11-2023)
Abstract
In the present study, bacterial endophytes were obtained from weeds of potato fields. Their antagonistic activity was screened against potato storage pathogen, Pectobacterium carotovorum subsp. carotovorum (Pcc) (JX029052), in the maceration assay. An endophytic strain, PC-2B was isolated from Convolvulus arvensis L. as a dominant weed of potato fields. In vivo application of this strain led to 58.8% reduction in tuber decay. This motile strain that can produce amylase was identified as Pantoea sp. using phenotypic features and 16S rRNA sequencing. Following PC-2B treatment, 56.7% Reduction in Disease Incidence (RDI) was obtained in preventative and 52% in curative challenges under semi-practical storage trails. Anti-Pcc bioactive compounds of Pantoea sp. was extracted and identified based on H NMR and FT-IR techniques. Two peptide antibiotics including Pantocin A and B with inhibitory effect against Pcc were characterized. These results might indicate that the tested Pantoea strain could be a promising candidate to protect potato tubers against soft rot disease caused by Pcc. However, large-scale complementary trials have to be conducted to validate these results before any recommendations.