Showing 10 results for Xanthomonas
Majid Amani, Nader Hassanzadeh, Saeid Rezaei,
Volume 1, Issue 1 (3-2012)
Abstract
In 2005, Circular to elliptical brown necrotic leaf spots, were observed on young leaves of Banana(Musa acuminata L.) plantion under plastic cover in Mazandaran&Gorgan provinces. The rhizomes and pseudostems were not affected. A gram-negativebacterium with yellow mucoid colonies was isolated from the leaves on sucrose and glucose nutrient agar. All isolates were negative in oxidas, and positive in catalase reaction. Non of isolates did not produce green or blue pigment on KB medium. On the basia of phenotypic charachteristics pathogenicity test was confirmed with inocoulation of bacterial suspension to Banana plants. The causal agent of bacterial necrotic and leaf spot of banana was recognized asXanthomonascampestris. This is the first report ofbacterial necrotic and leaf spot of banana in Iran.
Rasool Rezaei,
Volume 4, Issue 1 (3-2015)
Abstract
Rezaei R. 2015. Pathogenicity and virulence factors of plant pathogenic bacteria. Plant Pathology Science 4(1):23-33.
Plant pathogenic bacteria have evolved specialized strategies to infect their hosts. In this regard, the key virulence factors are effector proteins, cell wall degrading enzymes, toxins, extracellular polysaccharides and phytohormones. The interactions between plant pathogenic bacteria and their hosts have resulted in an evolutionary system between host defense responses and pathogen virulence factors. Pathogenic bacteria are continually under pressure to diversify their mechanisms to prevent host defenses and optimize nutrient availability. In turn, these virulence mechanisms have shaped the evolution of plant innate immunity. In this paper, the pathogenicity and virulence factors of plant pathogenic bacteria are discussed.
Nahid Gerayeli, Sareh Baghaee Ravari,
Volume 5, Issue 2 (8-2016)
Abstract
Gerayeli N. & Baghaee-Ravari S. 2016. The biological role of bacteriocins of gram-negative bacteria. Plant Pathology Science 5(2): 63-70.
Bacteriocins are a kind of antimicrobial peptides or proteins, produced by some gram-negative bacteria, for competition for space and resources, which can kill or inhibit closely-related bacteria. The producer bacterium is immune to these material by specific immunity proteins. Bacteriocins vary in size, microbial targets, mode of action and immunity mechanism. So far lots of bacteriocins that produced by specific isolates of gram-negative bacteria have been identified, which often have a high molecular weight. In this paper, mode of production, and mechanisms of action of bacteriocins, and their role in management of plants bacterial diseases, described.
Rasool Rezaei,
Volume 9, Issue 1 (3-2020)
Abstract
Rezaei R (2020) Effect of eight essential oils on bacterial canker disease in citrus. Plant Pathology Science 9(1):30-39. DOI: 10.2982/PPS.9.1.30.
Introduction: Citrus bacterial canker caused by Xanthomonas citri subsp. citri is an economically important disease in many tropical and subtropical countries. Several pathotypes of this pathogen have been described which, in addition to certain genotypic features, are distinguished above all by their geographical origin and their host range. Citrus bacterial canker disease is wide spread in Iran and a major threat to the production of Mexican lime (Citrus aurantifolia). Therefore, management of citrus canker is inevitable in citrus growing areas where citrus canker has been established. Application of copper-based bactericides is a standard control measure for management of citrus canker worldwide. Therefore, their long-term use leads to the development of resistant isolates. Plant extracts and essential oils with an antimicrobial effect have become particularly important as an environmentally friendly method for the treatment of plant diseases. Many researchers have recently focused on studying plant extracts and essential oils that contain antimicrobial compounds. Material and Methods: The present study was carried out on the antibacterial effect of Common yarrow (Achillea millefolium), Ginger (Zingiber offcinale), Golden marguerite (Anthemis tinctoria), Fennel (Foeniculum vulgare), Common sage (Salvia officinalis), Gum tragacanth (Astaragalus gossypinus), Summer savory (Satureja hortensis) and True cardamom (Elettaria cardamomum) against two pathotype of Xanthomonas citri subsp. citri under laboratory and greenhouse conditions. Results: All essential oils have an inhibitory effect on multiplication of Xanthomonas citri subsp. citri. The antibacterial test results showed that the essential oils of Ginger and True cardamom strongly inhibited the growth of Xanthomonas citri subsp. citri pathotype, especially the pathotype A*, whereas other essential oils showed moderate to weak activities. Conclusion: The essential oils of these eight plants, especially ginger and cardamom, have good potential for the management of citrus bacterial canker.
Ali Asghar Dehghan, Reza Ghaderi,
Volume 9, Issue 1 (3-2020)
Abstract
Dehghan AA, Ghaderi R (2020) Application of seaweeds in plant diseases management. Plant Pathology Science 9(1):101-107. DOI: 10.2982/PPS.9.1.101.
Algae are the most important plant growth stimulants due to their high content of minerals, amino acids, vitamins and growth regulators such as auxin, cytokinin and gibberellin. Use of these stimuli in crops can improve rooting, yield, photosynthetic capacity and their resistance to pathogens. Application of algae (mainly seaweeds) against various plant diseases including bacterial, fungal, viral and nematode diseases as well as pests has been proven. Seaweeds are used as a powder or extract mixed with soil, or foliar spray to control of plant diseases. They are usually involved in controlling plant pathogens by inducing plant resistance, antagonistic activity by induced activity of other microorganisms, and enhancing plant growth. In general, seaweeds can be applied as biofertilizers, biostimulators and soil amendments in integrated plant diseases management programs.
Saeid Ghahari, Somayeh Ghahari, Sajjad Ghahari, Ghorbanali Nematzadeh,
Volume 10, Issue 1 (2-2021)
Abstract
Ghahari S, Ghahari S, Ghahari S Nematzadeh GH (2021) The impact of Chinaberry, Colocynth and Camelthorn extracts on eight bacteria and three fungi. Plant Pathology Science 10(1):14-26. Doi: 10.2982/PPS.10.1.14.
Introduction: Antibacterial, antifungal and antioxidant activity of methanolic extracts of Colocynth (Citrullus colocynthis) seeds, Camelthorn (Alhagi maurorum) fruit and Chinaberry (Melia azedarach) leaves on eight bacteria and three fungi, which usually cause damage to agricultural products examined in this research. Material and Methods: Antimicrobial activity of selected plants in six concentrations on 11 microorganisms including, three gram-positive bacteria vs. Bacillus subtilis, Staphylococcus aureus, and Rathayibacter toxicus, and five gram-negative bacteria vs. Escherichia coli, Pseudomonas aeruginosa, Pseudomonas syringae subsp. syringae, Pseudomonas viridiflava, and Xanthomonas campestris pv. campestris, as well as three fungi vs. Pyricularia oryzae, Fusarium oxysporum and Botrytis cinerea was measured using the disk diffusion method. Also, the antioxidant activity of the extracts of these plants was evaluated by measuring the enzymes of catalase and guaiacol peroxidase and evaluating the ability to trap DPPH radicals. In addition, the amount of total phenols and flavonoids in these plants extracts were measured. Results: Methanolic extract of Colocynth seeds had the highest antibacterial activity, the highest activity of catalase and guaiacol peroxidase enzymes and the highest percentage of DPPH radical inhibition. Methanolic extracts of these plants had no effect on fungal colony growth. Conclusion: Methanolic extract of Colocynth seeds can be considered as potential sources of bactericides in agriculture.
Kavous Keshavarzi, Hadi Karimipour Fard,
Volume 10, Issue 1 (2-2021)
Abstract
Keshavarzi K, Karimipourfard H (2021) Bacterial diseases of walnut trees in Iran. Plant Pathology Science 10(1):107-116. Doi:10.2982/PPS.10.1.107.
Walnut is one of the most important fruit trees in Iran, which is always exposed to pathogens, especially bacteria. The three most important bacterial diseases of walnut in Iran are bacterial blight (Xanthomonas arboricola pv. juglandis), skin cankers (Brenneria nigrifluens, Brenneria rubrifacians) and crown gall (Agrobacterium tumefaciens). Bacteriological characteristics and pathogenicity of pathogenic bacteria, methods of managing these diseases, along with suggestions for identifying resistant genotypes of walnut trees by molecular methods are described in this article.
Hoda Taheri , Eidi Bazgir,
Volume 11, Issue 1 (3-2022)
Abstract
Taheri H, Bazgir E (2022) The role of autophagy in plants protection against pathogens. Plant Pathology Science 11(1):133-145. Doi: 10.2982/PPS.11.1.133.
Autophagy plays an important role in the process of plant development and interaction with pathogens such as fungi, bacteria, and plant viruses. Autophagy is linked to immunity and disease resistance through inhibition of programmed cell death (PCD) and is recognized as an important defense component in plants. Autophagy also helps selectively eliminate pathogens through specific interactions. A number of pathogens have acquired the ability to cope with or evade autophagy and use it to develop the disease. Some other pathogens also use the autophagy system as pathogenic factors. Therefore, understanding cellular processes such as responses related to autophagy genes are very important for studying pathological physiology and plant immunity. The role of autophagy in the immune system and the plant's defense response to pathogens is described in this article.
Dr. Mina Rastgou, Siroos Honarvar,
Volume 13, Issue 1 (2-2024)
Abstract
Rastgou, M., & Honarvar, S. (2024). Application of phages for biological control of plants pathogenic bacteria. Plant Pathology Science, 13(1),55-64.
Pathogenic bacteria are one of the most important factors in reducing the yield of plant products. In the past, the management of these pathogens was limited to the use of antibacterial compounds or resistance inducers, but with the discovery of bacteriophages in recent decades, attention to their use has increased. Bacteriophages or phages are viruses that specifically affect bacterial cells. Currently, hundreds of bacteriophages have been isolated and tested against plant pathogenic bacteria, and there are still many more that need to be investigated. This approach requires special protocols to identify new phages, understand the emergence of phage-resistant clones and the infectivity of other bacterial species. Phage therapy or the use of phages to biological control plant pathogenic bacteria due to its cheapness, very high specificity of phages against bacteria, no negative effect on humans or animals, and no environmental pollution, as a suitable method to control these pathogens can be considered.
Jafar Hematzadeh, Rasool Rezaei, Habiballah Charehgani, Fariba Ghaderi,
Volume 13, Issue 2 (9-2024)
Abstract
Rice is an important food crop in the world. Bacterial leaf blight, caused by Xanthomonas oryzae pv. oryzae, is one of the important diseases of rice that is prevalent in different cultivars in the world. Identifying and planting resistant or semi-resistant cultivars is the most effective method of disease management. This study aimed to investigate the reaction of four Iranian rice cultivars; Shiroodi, Setayesh, Fajr, and Hashemi, to the disease under field conditions. Rice plants with the disease symptoms were sampled from different regions of Kohgiluyeh and Boyer-Ahmad province in southwestern Iran, during 2012-2013. The pathogen was isolated from infected leaves after their surface disinfection, on Yeast extract-dextrose-CaCO3(YDC) medium. The isolated bacterium was rod-shaped, gram-negative, obligate aerobic, oxidase negative, catalase positive, levan and lecithinase positive. It induced a hypersensitivity reaction in tobacco leaves and could not hydrolyze starch, but it hydrolyzed gelatin, ascoline, and Tween 80. Based on a comprehensive analysis of morphological, biochemical, pathogenicity, and genotypic traits, the pathogen was identified as X. oryzae pv. oryzae. The reaction of these four Iranian rice cultivars to the disease was evaluated by inoculating them with the pathogen, monitoring the progression of disease symptoms, and measuring the growth of the bacterial population in each cultivar. There was a significant difference among the cultivars in terms of the length of leaf necrosis and the bacterial population within the tissue, with the Hashemi cultivar exhibiting the highest sensitivity and the Shiroodi cultivar showing the lowest sensitivity to the disease. The occurrence of bacterial leaf blight disease in Kohgiluyeh and Boyer-Ahmad province, as well as the reaction of these cultivars to the disease, are being reported for the first time.
