Showing 14 results for Bacterium
Meisam Taghinasab, Ebrahim Karimi,
Volume 1, Issue 2 (9-2012)
Abstract
The soft rot causal bacteria, species of Pectobacterium and Dickeya, are important pathogens of plants, which have worldwide distribution. These bacteria are very broad host range and cause plant tissues rot . Diseases caused by these bacteria in the form of soft rot, black stem, bulb rot and leaf spot of corn, rice, canola, sugar beet, potatoes, banana, dates, carrots, cabbage, onions, turnips, peppers, philodendron, pandanus, dieffenbachia, Cyclamen, Iris, Aglaonema, Dracaena, Gladiolus, Ficus, ornamental cactus, and Orobanche have been reported from Iran. Some varieties of field crops such as corn, tomatoes, potatoes and sugar beet, as tolerant to these bacteria in Iran.
Mehdi Sadravi,
Volume 2, Issue 1 (3-2013)
Abstract
Powdery mildew fungi are important obligate parasites of plants. They produce white cover on aerial parts of host plants, which then turn to yellow. The diseased plant becomes yellow and then wilted result in reducing quality as well as quantity of products in field and vegetable crops and also fruit trees. Among all of the control measures against powdery mildew, the most common method is application of the chemical fungicides, after disease incidence. Regarding to the hazards of agrochemicals and also considering the probability of incidence of resistant races of the pathogen, the biological control is considered as a safe and useful method for controlling the disease. The fungi Ampelomyces quisqualis, Pseudozyma flocculosa and Lecanicillium longisporum the bacterium Bacillus subtilis the mite Tydeus lambi and twenty-spotted lady beetle Psyllobora vigintimaculata , have been used effectively against the powdery mildew of cucumber, squash, tomato, pepper, grape and rose. Some of these biological agents have been introduced to the market, commercially.
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.
Vahid Ghazi-Mohseni, Seyed Kazem Sabbagh, Sedigheh Esmaili Bahabadi,
Volume 4, Issue 1 (3-2015)
Abstract
Ghazi-Mohseni V., Sabbagh S. K. & Esmaili Bahabadi S. 2015. Application of chitosan in plant diseases management. Plant Pathology Science 4(1):54-63.
Chitosan is a biodegradable natural compound derived from the bark of crabs and shrimp which have antimicrobial role against fungi and bacteria. Chitosan has directly effects on morphology of treated pathogens which reflect its fungistatical and fungicidal activity. It has been shown that chitosan increases production of glucanohydrolase, phenolic compounds and specific phytoalexin synthesis with antifungal activity and reduces enzymes such as polygalacturonase, pectin methyl-esterase that related to soft rot . In addition, chitosan can develop structural barriers via lignin synthesis. Therefore chitosan is considered as a new non-toxic biological material, inducer resistance of plants against diseases.
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.
, Rasool Rezaei,
Volume 5, Issue 1 (2-2016)
Abstract
Parad M. & Rezaei R. 2015. Citrus greening disease. Plant Pathology Science 5(1):37-47.
Citrus greening or Huanglongbing, is one of the most devastating disease of citrus worldwide. It is common in the southeast of Asia and is also recently reported from south provinces of Iran. It is caused by Liberibacter sp. that tend to colonize in phloem vessels of the host. This bacterium affects all of the main types of citrus plants and reduces fruit production. One of the identifying challenges is that some of the disease symptoms are similar to deficiency of some nutrient such as zinc. The most important vectors of the disease causal agent are some psylla species. The only worthwhile control measure is removing the microbial inoculums from the affected tissues. Management of the disease described in this paper.
Maryam Khezri,
Volume 5, Issue 2 (8-2016)
Abstract
Khezri M. 2016. Biofilm formation in probiotic bacterium Bacillus subtilis. Plant Pathology Science 5(2):52-62.
Most bacteria have a common ability to form communities known as biofilm. They are varied in structure and function, but have some similarities in general properties. The main compounds of biofilms are extracellular polysaccharides. The probiotic Bacillus subtilis is a gram-positive, rod-shape, endospore-forming and soil inhabiting bacterium that has many agricultural use, such as plant growth promoting activity and biocontrol potential against many of phytopathogens. Biofilm formation is an important microbial survival strategy that enables microorganisms to stay together for long time. Biofilm can protect the bacteria against unfavorable conditions, like antibiotics, chemical pesticides and biocide components. Capability of biofilm formation in probiotic B. subtilis plays significant role in root colonization and biological control of plant pathogens.
Meysam Azadi, Zabihollah Azami-Sardooei, Mehdi Azadvar,
Volume 8, Issue 2 (9-2019)
Abstract
AzadiMoghadam M, AzamiSardooei Z and Azadvar M (2019) Bacterial bark canker disease of walnut tree. Plant Pathology Science 8(2):38-44. DOI: 10.2982/PPS.8.2.38
Bacterial canker disease is one of the most destructive diseases of walnut trees that causes die back and plant decline and also great damages to quality and quantity of fruits. The disease can be observed in two forms, at depth and the surface of the bark which cause by two bacteria, Brenneria nigrifluens and B. rubrifaciens, respectively. The most important way of the pathogen penetration is the wounds in the trunk and branches which are occurred due to human activities or mechanical harvesting equipment. The disease becomes severe with the deep irrigation and when the nutrition is insufficient and temperature and humidity are high. Current paper explains history, importance, symptoms, biology, host range, sampling and isolation method also differential characteristics of bacteria and methods of disease management.
Hossein Pasalari,
Volume 10, Issue 1 (2-2021)
Abstract
Pasalari H (2021) The relationship between potato resistance to bacterial soft rot and expression of three PR genes. Plant Pathology Science 10(1):76-85. Doi: 10.2982/PPS.10.1.76.
Introduction: Changes in the resistance to bacterial soft rot in potatoes can be linked to the expression of pathogenesis-related (PR) genes. The aim of this study was to investigate the relationship between the accumulation of PR genes and the induction of resistance through infection of potato tuber cells with pathogenic bacteria at different temperatures in order to effectively combat bacterial soft rot disease in potatoes. Materials and Methods: Pectobacterium carotovorum 2A, Pectobacterium atrosepticum 36A, and Dickeya dadantii ENA49 were used in this study. For bacterial infection, the potato cultivars semi-resistant cultivar Scarab and susceptible cultivar Vesnianka, were used. The factorial experiment with three replications was carried out according to a completely randomized design. The relative level of mRNA copies of PR genes was determined by RT-PCR using primers of these genes. The mean values were compared according to the LSD test. Results: The experiments demonstrated the induction of PR-3, PR-5t and PR-10 in potato tuber cells in response to infection with P. carotovorum 2A, P. atrosepticum 36A and D. dadantii ENA49. It has been shown that the degree of induction of resistance genes depends on the temperature and the potato cultivar. Conclusion: It can be concluded that significant changes in potato resistance to bacterial soft rot at temperatures of 28 and 33 ° C are associated with the expression of these PR genes.
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.
Kayvan Farri, Maryam Khezri,
Volume 10, Issue 2 (9-2021)
Abstract
Farri K, Khezri M (2021) Integrate management method of plants crown gall disease. Plant Pathology Science 10(2):116-127.
Doi: 10.2982/PPS.10.2.116.
Agrobacterium tumefaciens is capable of causing distractive disease of crown gall in a wide range of dicotyledonous plants and causes great economic impact in its hosts. This soil-dwelling bacterium can survive as a saprophyte in soil and plant debris for a long time. When the host plant is present, the bacterium is absorbed into the plant through the root secretions from the wounds and enters the plant through it. The pathogenic bacteria introduce a part of its Ti plasmid, called T-DNA, into the plant cell. Integration of the T-DNA to plant cell genome results in expression of the encoded oncogenes and an increasing the production of phytohormones in cells. Overproduction of auxin and cytokinin leads to cells hyperplasia and hypertrophy, which results in the gall formation on the root, crown, and branches of infected plants. As regards the wide host range, high economic impact, and difficult control of this disease, in this article phenotypic, genetic and pathogenicity characteristics of bacteria have been studied, as well as biology and effective strategies of integrated disease management are presented.
Meysam Bakhshi Ganje,
Volume 11, Issue 1 (3-2022)
Abstract
Bakhshi Ganje M (2022) Acute oak decline disease. Plant Pathology Science
11(1):122-132. Doi: 10.2982/PPS.11.1.122.
Abstract
Acute oak decline with signs of canker and colored discharge on the trunks of old trees has been reported in northern Iran for the past two decades. Several bacteria of the order Enterobacterales, the family Pectobacteriaceae and the genus Brenneria were isolated and identified from diseased trees. Although oak possesses several genes whose products are responsible for plant resistance to fungal pathogens, bio-trophic pathogens, hemibiotrophic pathogens, and water stress, it does not show resistance to these necrotrophic pathogenic bacteria. The mechanism of the occurrence and epidemic of acute oak decay is the predisposition of trees to successive droughts, the outbreak of some pests, and the relatively low rate of development of oak defense genes against the high rate of evolution of pathogenic genes of necrotrophic bacteria such as Brenneria species. Due to the many climate changes in recent years, there may be an epidemic of the disease in the forests of other parts of the country in the future. This article describes research into the disease to pave the way for an appropriate method of disease management.
Zahereh Panahi, Reza Khakvar, Naser Aliasgharzad, Saeed Zehtab, Reza Farshabf Pourabad,
Volume 12, Issue 1 (3-2023)
Abstract
Panahi, Z., Khakvar, R., Aliasgharzad, N., Zehtab, S., & Farshbaf PourAbad, R. (2023). The effect of copper nanoparticles on soft rot agent of potato, carrot and onion. Plant Pathology Science, 12(1), 1-11.
Introduction: Bacterial soft rot caused by Pectobacterium species is one of the important and common diseases in Potatoes and vegetables. Disinfection of tubers or seeds with chemicals is one of the methods of disease management. Copper nanoparticles, like silver and gold nanoparticles, have a strong inhibitory effect on bacterial cells, but they are much cheaper and more accessible than them. This research was conducted to determine the effect of copper nanoparticles alone and in combination with oxytetracycline and streptomycin antibiotics on potato, carrot and onion soft rot. Materials and Methods: The pathogen was isolated from rotten tissues of potato, carrot and onion, purified and identified by studying the phenotypic and genetic characteristics of the Pel-gene region using Pectobacterium specific primers (Y1 and Y2). The effect of copper nanoparticles, oxytetracycline and streptomycin, and their combination with copper nanoparticles on the pathogen growth was investigated in a completely randomized design experiment with three replications for each treatment in vitro. Results: Pectobacterium odoriferum was identified as pathogen based on phenotypic characteristics and genetic affinity. Streptomycin compared to oxytetracycline inhibited the pathogen growth more and their effect in combination with copper nanoparticles increased by 12 and 19.5%, respectively. Conclusion: Copper nanoparticles can inhibit the growth of P. odoriferum, and in combination with antibiotics increase their effect.
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.
