Showing 9 results for Pseudomonas
Robab Ezazi, Masoud Ahmadzadeh,
Volume 3, Issue 2 (9-2014)
Abstract
Abiotic stresses are major environmental factors that affect agricultural productivity worldwide. Depending on the crop, the yield losses associated with abiotic stresses can reach 50 to 82 percent. Extreme temperatures, drought, salinity, flooding, freezing, ultraviolet light, heavy metals, nutrient deficiency, unsuitable pH, air pollutants and mechanical damage are the most basic stressors. Because biotic stresses cause metabolic toxicity, membrane degradation, reduction of photosynthesis, decrease of nutrient uptake, changes in levels of phytohormones and ultimately affect the plant growth and its productivity, therefore reducing the effect of these stresses, is essential. Plant growth promoting rhizobacteria play an important role in plant disease management and have a high potential in alleviation the abiotic stresses.
Ali Baradar, Roohallah Saberi Riseh, Ebrahim Sedaghati, Abdolreza Akhgar,
Volume 4, Issue 1 (3-2015)
Abstract
Baradar A., Saberi Riseh R., Sedaghati E. & Akhgar A. 2015. Mycorrhiza helper bacteria.
Plant
Pathology Science 4(1):46-53.
Mycorrhizal fungi increase water and nutrient elements absorption to the plant and plant provide carbohydrates for the fungus and this is beneficial for both parties . Many plants need to these fungi for absorption some mineral elements and resistance to environmental stresses such as drought, soil contamination to heavy metals such as lead, zinc and cadmium. Some soil borne bacteria have been identified as third part of the mycorrhiza, which cause improving the performance of this symbiotic relationship, and have been named as mycorrhiza helper bacteria.
Amir Ramzani, Dr Safarali Mahdian,
Volume 5, Issue 1 (2-2016)
Abstract
Ramezani A. & Mahdian S. A. 2016. Biological control of post-harvest citrus diseases. Plant Pathology Science 5(1):14-25.
Post- harvest rot of citrus fruits is one of the most important limiting factors that reduce the life of harvested products and are one of the most important economical diseases in world’s citrus production areas. Two most important fungi that affect the citrus fruits, are green and blue molds which are produced by Penicillium digitatum and P. italicum, respectively. The disease are mainly managed by using the synthetic fungicides, but because of environmental hazards and appearance of resistant strains of the pathogen, the biological control by the use of bacterial, fungal and yeast antagonists can be suggested. The efficiency of yeasts such as Candida guilliermondii, C. saitoan, Pichia guilliermondi and Aureobasidium pullulans; the bacteria Pseudomonas fluorescens, Bacillus subtilis, Pantoea agglomerans and the fungus Muscodor albus, in controlling the green and blue molds of citrus is reported so far. In this paper, we tried to explain the method of biological control with emphasizing on the identification of useful microorganisms and their operation.
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.
Morteza Golmohammadi , Sayyid Najme Banihashemian ,
Volume 6, Issue 2 (9-2017)
Abstract
Golmohammadi, M. & Banihashemian S. N. 2017. Management method of citrus blast disease. Plant Pathology Science 6(2):1-13.
Citrus bacterial blast is reported from many parts of citrus growing areas of world. It is one of the most important diseases of citrus in north of Iran, but its damage is different because of year-to-year climate variability. The disease is caused by two species of Pseudomonas. In those years that air humidity and temperature are suitable, these bacterial species can cause serious damage to citrus trees. The main symptom of citrus blast disease is wilting and dieback of branches. Some practices for management of this disease are illustrated in this article.
Samaneh Samavat,
Volume 6, Issue 2 (9-2017)
Abstract
Biological control of Rhizoctonia damping-off disease. Plant Pathology Science 6(2):55-67.
Damping-off caused by Rhizoctonia solani J. G. Kühn is a very important plant disease among soil-borne diseases that make severe damages on a wide range of plants in the world. Biological control of this disease with Trichoderma, Gliocladium, Bacillus, Pseudomonas and Rhizobium species has been reported as a successful management method. The results of some researches on this area and the mechanisms of the effect of these antagonistic fungi and bacteria are described here.
Aminallah Tahmasebi, Mohamad Hamed Ghodoum Parizipour,
Volume 9, Issue 1 (3-2020)
Abstract
Tahmasebi A, GhodoumParizipour MH (2020) The role of brassinosteroid hormones in plant response to pathogens. Plant Pathology Science 9(1):108-117. DOI: 10.2982/PPS.9.1.108.
Plants are usually attacked by several pathogens. Different defense pathways in plants have evolved in reaction to pathogens. Plant defense responses have been shown to be regulated by various plant hormones. Brassinosteroids are plant-specific steroid hormones that play important roles in regulating growth and developmental processes. In addition to acting as a regulator of plant growth, they also play a role in defense responses to pathogens. Many researches have been done on their role in plant resistance to fungi, bacteria and viruses, which are described in this article. Further understanding of the role of these hormones in plant defense responses can be useful in inducing resistance or producing plants resistant to pathogens.
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.
Roghayeh Mohammadi, Mansureh Keshavarzi, Nader Hassanzadeh, Jalil Dejampour, Afagh Farhadnezhad,
Volume 10, Issue 2 (9-2021)
Abstract
Mohammadi R, Keshavarzi M, Hassanzadeh N, Dejampour J, Farhadnejad A (2021) Relative resistance levels to bacterial canker in Iranian apricot hybrids. Plant Pathology Science 10(2):15-29. Doi: 10.2982/PPS.10.2.15.
Introduction: Bacterial canker caused by Pseudomonas syringae is one of the most damaging diseases in apricots. This experiment was conducted to evaluate relative resistance to the disease in 22 selected local apricot hybrids including AD507, AD405, and HS731 which were recently released as Jalil, Parsi and Shanli. Material and Methods: Evaluation methods included artificial inoculation of two-year-old seedlings in an orchard and of cut shoots in the laboratory. Initially, the pathovar identity of localP. syringae strains were determined using LOPAT and GATTa tests and three isolates were used as inoculum. The inoculation was done in the seedling stem and after one year and 1.5 years, canker length was recorded. Result: The pathovar of all isolates was identified as P. syringae pv. syringae. The longest and shortest cankers were observed in AD1033 and AC113 with averages of 34.76 mm and 8.35 mm, respectively. The cut shoot bioassay was not practical for apricots. The hybrids were classified into four groups including highly resistant, resistant, moderately resistant, and susceptible. Conclusion: AD1033, AD1042, AD940, AD811, HS210, DM101, HS203 have been classified as susceptible and should not be used in breeding programs and orchard establishment/replacement. Jalil, Parsi, and Shanli were rated as resistant, and moderately resistant, respectively.
