Plant Pathology Science

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.

Motieeyan  L.  &  Nasr-Esfahani  M.  2016. Management  method of sugar beet cyst nematode. Plant Pathology Science 5(2):32-41.

Sugar beet, is one of the basic source of the raw material for sugar industry in Iran. The beet cyst nematode, Heterodera schachtii Schmidt, 1871, is one of the most damaging pathogens of sugar beet. This nematode has a wide host range, including 218 plant species from 95 genus and 23 families, which include some of the important field crops, ornamental plants and weeds. Nematode management methods include avoiding of cultivation in highly infested soils, disease scape by early cultivation, crop rotation, using resistant varieties, application of bioagents, applying of organic fertilizers, animal manure, plant waste materials, compost, vermicompost and also soil solarization and chemical control are described here.

Najafiniya  M.,  Bagheri  A., Azadvar M. & Salehi M. 2016. The situation of witches broom disease of sour lime in Iran. Plant Pathology Science 5(2):23-31.

Lime is one of the most important economic and horticultural plants in the southern part of Iran. Among the diseases of citrus in south of Iran, Witches Broom Disease of Lime (WBDL) is one of the major citrus diseases. The causal agent of WBDL is a phytoplasma with the proposed name, Candidatus Phytoplasma aurantifolia. The symptoms of disease start with appearance of witches broom at one-side of the infected tree. The disease then spread to whole parts of plant showing leaf proliferation, shortened internodes, small and pale green leaves, no formation of any spine, flower or fruit and finally death of the infected plants. To control the disease, integrated management and cultural practices has shown to be effective methods. Elimination of symptomatic trees as well of the newly emerged infected branches, chemical or mechanical weed control and a periodic spraying by systemic pesticides against the vector insect, or a combination of these methods is highly recommended. Among the control measures, chemical control of the vector has showed is very effective for reducing the disease spread and severity.

Rahmani  H. R. &  Mohamadi-Goltapeh E. 2016. Six forest species of truffles. Plant Pathology Science 5(2):1-12.

Edible mushrooms that are known as the truffle are classified in apothecial ascomycetes. They are obligate ectomycorrhiza of plants and produce their fruiting bodies on or below the surface of the soil. The genus Tuber belongs to the order Pezizales, class Pezizomycets, and has numbers of species with universal distribution. So far, France, Italy, United Kingdom and New Zealand have tried for the commercial production of truffle. Among the species of edible truffle of the universe, two valuable species, the white truffle, T. magnatum, and the black truffle, T. melanosporum, are the most valuable species. Because of their economic and medicinal importance, this is necessary to perform scientific research for their accurate identification.

Safaiefarahani B. & Mostowfizadeh-Ghalamfarsa  R. 2017. Phytophthora spp. interspecific hybrids and their danger for agriculture. Plant Pathology Science 6(1): 33-46.

Interspecific hybridization is an important evolutionary process contributing to adaptation and speciation. During the last decade, advances in the molecular taxonomy techniques have led to increasing the number of descriptors interspecific hybrids in the genus Phytophthora. In Phytophthora hybrids, inheriting and recombining genes from both parents may result in increased aggressiveness and broader host range compared with either parent. Some Phytophthora natural hybrids have also been reported in Iran to date. Consequently, identification, pathogenicity and host range tests of these hybrids as well as preventing the formation of new hybrids before experiencing large economic losses are recommended for management of plant diseases caused by this fungal-like organisms.

Abootorabi E. 2017. Four marigold species as control agents of root knot nematodes. Plant Pathology Science 6(1):68-79.

The Root knot nematodes (Meloidogyne spp.) are major limiting factors in growing many agricultural crops. With the aim of producing a healthy crop, cultivation of some plants with allelopathic effects on nematodes is one of the most effective control measure against root knot nematodes. This method can be used as an excellent substitute of chemical treatment. Marigolds (Tagetes spp.) are herbaceous plants of family Astraceae with more than 50 species, can be used as ornamental cover crops. Nematicidal effects of marigolds on several nematodes had been proved. Marigolds produce alpha-terthienyl enzyme, which can control root-knot nematodes and other pests and pathogens such as fungi, bacteria and insects. It also has positive role in promoting growth of bedding plants. In this article, important marigold species including Tagetes tenuiifolia Cav., T. minuta L., T. patula L. and T. erecta L., have been introduced.

Bagheri  A. 2017. Situation of  potato common scab disease in Iran. Plant Pathology Science 6(1):47-56.

Common scab disease of potato has been reported from all of the potato growing regions of the world. Potato scab is one of the serious diseases of potato in Iran. Integrated disease management program on reducing the potato scab in the country, needs to verify the key factors affecting the occurrence and spread of the disease. Growing the potato plants in a soil with a neutral pH with a constant moisture, sprinkler irrigation, crop rotation and a good weed control program, especially against convolvulus, are effective methods for disease control. The use of organic fertilizers and the use of resistant varieties are recommended also. The importance of the bacterial scab of potato, distribution and intensity of infection, disease symptoms, factors affecting the disease severity, disease cycle, response of the common potato cultivars to the disease, the dominant causal bacterial species in Iran and integrated management of disease that were carried out in Iran and other countries, are described in this article.

Nowadays, control of plant pathogens and weeds is more difficult and expensive than in the past. In last decades, due to adoption of inappropriate management methods and excessive use of agrochemicals, the soil fauna and flora threatened. Accordingly, many of ecologists and plant pathologists tried to find some alternative methods of pest and pathogen control. Soil solarization is of these approaches that is widely used against soil pathogens. This is an ecofriendly and safe as well as low cost and efficient method which can be used to control the plant pathogens, pests and weeds. As a part of integrated pest management program, this approach applies the ecological principles to protect the environment and reduce the hazards of pesticides. In this review, we have described the history and benefits of soil solarization and also the principles of this method

Abdollahi M. & Fatemi E. 2017. Review of  new approaches  in  nematodes  taxonomy. Plant Pathology Science 6(1): 1-11.

Use of advanced methods in nematode taxonomy and biodiversity is growing rapidly. Because the morphological and morphometric characterstics of nematodes are not enough for accurate nematode identification, the modern techniques were estsblished to terminate the taxonomic challenging. According to the progress achieved, some new approaches such as molecular studies have enhanced the nematode diagnosis. Numbers of molecular techniques like RAPD, RFLP, AFLP, ISSR and SCAR have been established to give confirmation to traditional detection, especially for identification of undescribed species. In this review, every one of each new technique is discussed.

Rahimizadeh M. & Sadravi  M. 2016. Eight useful Aspergillus species. Plant Pathology Science 6(1): 22-32.

Aspergillus species are saprophytic fungi which can live on plant debris in the soil and water and also on some plant products, stored fruits and grains. They can be identified by studying the features of colonies, conidiophores, vesicles, phialids and conidia, on selective culture media. The biocontrol potential of some isolates of A. flavus, A. fumigatus, A. niger, A. piperis, A. repens, A. tamarii, A. terrus and A. tubingensis, against some plant diseases such as cocoa black pod, root galls and Fusarium root rot of tomato, Alternaria leaf spot, Fusarium dry rot, potato pink and soft rot of tubers has been proven. They also can act as plant growth promoter and aflatoxin reducer agent in seeds and nuts. Key morphological characteristics of these eight species of Aspergillus is described in this paper. Most of these species are reported from Iran, thus identification and application of their efficient isolates can be suggested in plant diseases management as well as the plant growth enhancement programs.

Sadravi  M.  & Moradi N. 2017. Four important oak trees diseases in Iran. Plant Pathology Science 6(2):14-23.

Zagros Mountains in the west of Iran and some areas in the north of Iran are covered by oak trees. Four important diseases of Iranian oak trees are charcoal rot, chestnut blight, sudden death and powdery mildew. The symptoms of these diseases and the characteristics of pathogens as well as their prevalence are described in this article. Some strategies for protecting the oak trees from these diseases are also proposed here.

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.

Hoseinzadeh A., Davari M. and Habibi-Yangjeh A. 2017. Applications of nanomaterials in the fungal plant diseases management. Plant Pathology Science 6(2):68-77.

The use of nanotechnology in plant disease management has been seriously considered by researchers in recent years. Some of these reteaches have shown the antifungal effects of nano zinc oxide on Botrytis cinerea and Penicillium expansum; nano copper oxide on Aspergillus flavus; silver nanocomposite compounds (SiO₂/Ag₂S) on Aspergillus niger; Fe₃O₄/ZnO/AgBr on Fusarium graminearum, F. oxysporum and Botrytis cinerea, and carbon nanomaterials on F. graminearum. Their antifungal mechanisms are including: degradation of lipid and protein, damage to cell membranes, water channels blocking by nanomaterials and loss of spore water and plasmolysis and the inhibition of growth or destruction of fungal hyphae and prevent the sporulation.

Keshavarzi M. 2018. Olive  quick  decline  syndrome  disease. Plant Pathology Science 7(1):40-50.

Quick Decline Syndrome of Olive caused by Xylella fastidiosa subsp. pauca, is currently spread in some European countries in Mediterranean Sea area and there is a risk of its spread beyond the Middle East. The initial symptom is marginal leaf blight, then fruit drop and shoot dieback appears. Growing multiple suckers and finally death of whole tree are the other symptoms. In addition to olive, almond and oleander are also susceptible to this pathogen. The characteristics, biology, host range, transmission and distribution routes of the causal agent are described. In addition, disease prevention and management methods are proposed here. 

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