Plant Pathology Science

Six Forest Species of Truffle

Ebrahim Mohamadi goltapeh

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.

Cercospora Leaf Spot Disease of Sugar Beet

Mahdi Arzanlou

Mousavi S. & Arzanlou M. 2016. Cercospora leaf spot disease of sugar beet. Plant Pathology Science 5(2):13-22.

Cercospora leaf spot disease is one of the most important foliar diseases of sugar beet. Over one third of the sugar beet cultivation areas of the world has been affected by this disease. Cercospora beticola is the causal agent of this disease and a high level of interspecific variation of its morphology and genetics has been reported. Disease management is mainly achieved by a combination of cultural practices, cultivation of resistant varieties and application of fungicides. Due to the economic importance of the disease in Iran, some of the different aspects of Cercospora leaf spot disease, including the introduction of disease as well as the biology of the fungus, disease cycle and the efficient measures of disease management, has been reviewed in this paper.

The Situation of Witches Broom Disease of Sour Lime in Iran

Mousa Najafiniya

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.

Management Method of Sugar Beet Cyst Nematode

Mehdi Nasr esfahani

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.

Integrated Management of Rhizoctonia Root Rot of Bean

Bita Naseri

Naseri B. 2016. Integrated management of Rhizoctonia root rot of bean. Plant Pathology Science 5(2):42-51.

Rhizoctonia root rot caused by Rhizoctonia solani Kühn seriously reduces bean yield. Restricting wide distribution of the disease in main bean growing regions requires identification of factors effect on the disease occurrence and prevalence. Due to the lack of resistant cultivars and ineffective chemical control measures, cultural practice management plays an important role in disease control. According to the findings, increasing soil organic matter, improving rhizoobial nodule formation on root, not planting beans in sandy soils, maintaining nuteral pH of field soil, following 7-9 days irrigation interval throughout growing season, planting standard density of 30 plants per square meter, seeding at less than five cm depth under warm and dry climatic conditions, using sprinkler irrigation, growing red bean in infected fields, appropriate rotation program, applying maximum 50 kg/ha urea, weed control, and seed treatment with proper systemic fungicide should be considered in an integrated management program.

Biofilm Formation in Probiotic Bacterium Bacillus subtilis

Maryam Khezri

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.

The Biological Role of Bacteriocins of Gram-Negative Bacteria

Sareh Baghaee Ravari

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.

Role of Endophytic Bacteria in Sustainable Agriculture

Behrouz Harighi

Etminani F., Etminani A. & Harighi B. 2016. Role of endophytic bacteria in sustainable agriculture. Plant Pathology Science 5(2):71-80.

Food security is one of the most challenges in the world. This problem is more important in regions with unsuitable agricultural system conditions. Use of chemical pesticides to protect crops against plant pathogens and insects has been increasing over the last decades. Chemical fertilizers increase the yield but usually reduce soil fertility and harm to environment. Therefore, application of endophytic bacteria as alternative fertilizers can be used in sustainable agriculture without affecting environment. Endophytic bacteria use various mechanisms to enhance plant growth such as nitrogen fixation, solubilization of phosphate, production of phytohormones like auxin, cytokinin and gibberellin, production of Hydrogen cyanide and Siderophore as an antimicrobial compounds to control of soilborne disease and increasing plant resistance to abiotic disorders. Knowledge about endophytic bacteria- plant interaction can provide effective strategy to develop sustainable agriculture in order to ensure yield improvement without affecting environment.

Management of Wheat Rusts

Taha Dadrezaei

Dadrezaei S. D. & Torabi M. 2016. Management of wheat rusts. Plant Pathology Science 5(2):81-89.

Wheat is the most important crop in the world and rust diseases cause the most damage to wheat all over the years. There are so many ways to control the disease that the use of resistant cultivars is the most effective and economic way for disease control. Rust has high pathogenicity diversity and evolutionary aptitude. On the other hand, migration and mutation leads to the emergence of non-native races of rusts in a region so virulent pathotypes with the new structures and violence on resistance genes in commercial resistant cultivars were incidence and cause disease in resistant varieties and spread in the wheat fields. Development of effective and sustainable control methods against plant diseases is very much dependent on our knowledge of the disease in our country. This paper introduces wheat important rusts diseases and explains Factors affecting the prevalence, distribution, and relation of air currents in the transmission of rusts and strategies for monitoring and management of rusts in the country.

Molecular Plants Defense Mechanisms Against Nematodes

Salar Jamali

Sadeghi L. & Jamali S. 2016. Molecular plants defense mechanisms against nematodes. Plant Pathology Science 5(2):90-100.

Plant parasitic nematodes can devastate a wide range of crop plants. They are obligate parasites and have evolved compatible parasitic relationship with their host plants to obtain nutrients that are necessary to support their development and reproduction. Suppression of host defense is a key step for pathogenesis in the compatible interaction. Plant defense response is activated from the moment a nematode penetrates the plant root. Stylet and secretions of esophageal glands play central roles at during invasion to host, migration inside the roots and establishment of feeding site on host cells. New findings demonstrate that secretions of esophageal glands of some nematodes as effectors deliver into the apoplast and cytoplasm of host cells to active plant defense responses in resistant host. Molecular plants defense mechanisms against nematodes described in this paper.