Reliable and specific detection and identification of Brenneria goodwinii, the causal agent of oak and oriental beech decline

Chestnut-leaved oak (Quercus castaneifolia) and oriental beech (Fagus orientalis) are among the major tree species in the Hyrcanian forests. Brenneria goodwinii was identified as the causal agent of necrotic lesions and stem bleeding on affected oak trees in different countries. Oak and oriental beech trees with bleeding symptoms were observed in a few forest sites in northern Iran. The objectives of the present study were to identify and characterize the causal agents of bark canker in oak and oriental beech trees and develop a primer set for specific detection, using polymerase chain reaction (PCR), of Brenneria goodwinii strains. A total of 31 and 20 samples from oak and oriental beech trees, respectively, with stem bleeding and bark canker symptoms were collected from Golestan and Mazandaran forests in northern Iran in 2020–2021. Bacterial strains displaying a green metallic sheen on EMB-agar medium were isolated from symptomatic oak (105 strains) and oriental beech samples (32 strains), while 31 and 20 strains were also isolated from healthy oak and oriental beech, respectively. Pathogenicity tests indicated that 51 and 25 strains isolated from oak and oriental beech, respectively were able to induce a necrotic area on oak acorns 15 days following inoculation. Moreover, four and two representative strains inoculated on oak and oriental beech twigs, respectively induced necrosis on all inoculated green twigs 1 month after inoculation. The sequences of the 16S rRNA and gyrB genes of representative strains isolated from and proved pathogenic on oak and oriental beech trees were 100% and over 99% similar to B. goodwinii LMG 26270T, respectively, which revealed the strains belong to B. goodwinii species. The primer pair BgF3/R2, which was designed to target the hrpN gene, was proven to be specific in the detection of B. goodwinii strains. The primer pair amplified a 618-bp DNA fragment from strains of B. goodwinii only and not from strains belonging to Rahnella, Gibbsiella, Lonsdalea, and the other Brenneria species among several other pathogenic bacteria tested. No fragment was amplified from DNA extracted from healthy trees or seedlings in PCR using this primer pair

Electrophoretic Analysis of Total and Membrane Proteins of Xanthomonas campestris Pathovars, the Causal Agents of the Leaf Streak of Cereals and Grasses in Iran

Forty‐five Iranian isolates of Xanthomonas campestris obtained from wheat, barley and grasses were compared with reference strains using polyacrylamide gel electrophoresis (PAGE) of the whole‐cell and membrane proteins. The PAGE profiles of the whole‐cell and membrane proteins of the Iranian isolates obtained from barley, with the exception of IBLS 11 and IBLS 12, were identical and clearly distinguishable from those of the other isolates. The barley group isolates, which were pathogenic only to barley, were similar to UPB 458 (NCPPB 2389), the reference strain of pathovar hordei. The isolates obtained from wheat and grasses, as well as IBLS 11 and IBLS 12, which can infect wheat, barley and some wild grasses, had similar banding patterns: only IBLS 40 isolated from Hordeum sp. displayed the same profile as the barley group. Reference strains UPB 443 (NCPPB 2821) and UPB 513, which correspond to pathovars undulosa and translucens , respectively, were related to the wheat group. IBLS45, isolated from Bromus sp., had a banding pattern that differed from those observed for strains of the barley and wheat groups. The results suggest that this method can be useful for discriminating different pathovars of X. campestris attacking cereals and grasses, and sodium dodecyl sulphate (SDS)‐PAGE of membrane proteins was not more sensitive than SDS‐PAGE of total proteins for differentiating the isolates

Comparing the expression levels of mRNA for MMP-7 in gastric mucosa of patients with H. pylori infection and uninfected patients

Background and purpose: The expression of growth factors, proteolytic enzymes, fibrogenic factors, and cytokines are altered in Helicobacter pylori (H. pylori) infected gastric mucosa. Matrix metalloproteinases (MMP) are a family of zinc-dependent homologous enzymes digesting most of the components of the extracellular matrix and basement membrane and are involved in remodeling and functioning of the biological processes. The purpose of this study was to compare gene expression of matrix metalloproteinase-7 (MMP-7) in patients with H. pylori-infected and uninfected individuals with gastrointestinal diseases. Materials and methods: This study was conducted in 50 H. pylori-negative patients and 50 H. pylori-positive patients being admitted to Shahrekord Hajar Hospital due to gastrointestinal diseases in 2014. The participants’ demographic information was collected and sampling was done. First DNA was extracted, and then PCR was performed to check for the presence of 16sRNA and UreC. The RNA from each sample was also extracted and cDNA was prepared. Afterwards, the expression of MMP-7 was measured by real time-PCR using specific primers and probes. Results: MMP-7 mRNA expression was significantly higher in biopsies of H. pylori-infected patients compared to that in H. pylori-uninfected patients (P<0.0001). Conclusion: Increased expression of MMP-7 can be effective in inflammatory response and development of the disease. It could be used as a key marker for early diagnosis of gastrointestinal diseases and gastric cancer. © 2016, Mazandaran University of Medical Sciences. Engineering. All rights reserved

Association of Dryocola boscaweniae, Gibbsiella greigii and Gibbsiella quercinecans with oak decline in Iran

Tree decline is described as the loss in tree vigor and increased mortality initiated by climate change events, and also involves pathogens and pests. Stem bleeding and bark canker of oak (Quercus castaneifolia) were observed in Mazandaran and Golestan forests during summer 2020–2021. Symptoms included cracks in the outer bark, stem tissue necrosis, bleeding, dark exudate and dark brown lesions in the inner bark. Eighty-nine strains with a metallic green sheen pigment were isolated on eosin methylene blue agar. The pathogenicity of all strains recovered in this study was assessed on oak seedlings and acorns. Forty-four strains produced rotting on oak acorns 2 weeks after inoculation. Inoculation of six representative strains on oak seedlings resulted in twig dieback of the plants after 4 weeks. Strains were negative for Gram reaction, oxidase and levan formation from sucrose. The gyrB and infB gene sequence similarity values of strains were 98.87–99.57% with the type strain of Gibbsiella quercinecans, 98.66–98.86% with the type strain of Gibbsiella greigii and 99.46–99.64% with the type strain of Dryocola boscaweniae. In the phylogenetic tree based on concatenated sequences of gyrB and infB genes or each gene individually, the strains were divided into three clusters containing the type strains of G. quercinecans, G. greigii and D. boscaweniae, each with high bootstrap support and confirming their identity as belonging to these three species. To the best of our knowledge, this is the first report of oak bacterial canker caused by D. boscaweniae, G. greigii and G. quercinecans in Iran and the first report of D. boscaweniae associated with oak decline symptoms

Polyphasic Characterization of Pseudomonas orientalis, a New Causal Agent of Citrus Blast Disease in Iran

Trabajo presentado en el Iranian Plant Protection Congress College of Agriculture and Natural Resources, celebrado en Karaj (Iran), del 1 al 3 de enero de 2016Peer Reviewe

Recent Achievements in the Taxonomic Position of the Citrus Blast Disease Causal Agents

Trabajo presentado en el Iranian Plant Protection Congress College of Agriculture and Natural Resources, celebrado en Karaj (Iran), del 1 al 3 de enero de 2016Peer Reviewe

Pseudomonas caspian sp. nov.

Trabajo presentado en la Reunión del Grupo Especializado en Taxonomía, Filogenia y Biodiversidad de la SEM, celebrada en Santiago, España, del 8 al 10 de junio de 2016Peer Reviewe

New <i>Pseudomonas</i> spp. Are Pathogenic to Citrus

<div><p>Five putative novel <i>Pseudomonas</i> species shown to be pathogenic to citrus have been characterized in a screening of 126 <i>Pseudomonas</i> strains isolated from diseased citrus leaves and stems in northern Iran. The 126 strains were studied using a polyphasic approach that included phenotypic characterizations and phylogenetic multilocus sequence analysis. The pathogenicity of these strains against 3 cultivars of citrus is demonstrated in greenhouse and field studies. The strains were initially grouped phenotypically and by their partial <i>rpoD</i> gene sequences into 11 coherent groups in the <i>Pseudomonas fluorescens</i> phylogenetic lineage. Fifty-three strains that are representatives of the 11 groups were selected and analyzed by partial sequencing of their 16S rRNA and <i>gyrB</i> genes. The individual and concatenated partial sequences of the three genes were used to construct the corresponding phylogenetic trees. The majority of the strains were identified at the species level: <i>P</i>. <i>lurida</i> (5 strains), <i>P</i>. <i>monteilii</i> (2 strains), <i>P</i>. <i>moraviensis</i> (1 strain), <i>P</i>. <i>orientalis</i> (16 strains), <i>P</i>. <i>simiae</i> (7 strains), <i>P</i>. <i>syringae</i> (46 strains, distributed phylogenetically in at least 5 pathovars), and <i>P</i>. <i>viridiflava</i> (2 strains). This is the first report of pathogenicity on citrus of <i>P</i>. <i>orientalis</i>, <i>P</i>. <i>simiae</i>, <i>P</i>. <i>lurida</i>, <i>P</i>. <i>moraviensis</i> and <i>P</i>. <i>monteilii</i> strains. The remaining 47 strains that could not be identified at the species level are considered representatives of at least 5 putative novel <i>Pseudomonas</i> species that are not yet described.</p></div