Plant Pathology Science

Shenavar  O. & Mostowfizadeh-Ghalamfarsa  R. 2015. Computerized interactive keys for identification of fungi. Plant Pathology Science 4(2):41-52

Accurate identification of fungi and fungus-like organisms is one of the most important steps for finding an approach to employ or control them. Nevertheless, this process is usually laborious and slow. Application of interactive keys is one of the ways to save the time and have an accurate identification of the species. An interactive key is a computer program in which the user enters morphological or molecular attributes of the specimen and the program compares them with the data of its database to find a match species with the highest similarity.  Such keys also allocate separate images and other data for any known species. In this paper some of the interactive identification keys and their function is discussed.

Rahmani H. R., Mohammadi Goltapeh E. & Safaie N. 2015. The role  of  endophytic fungus Pirifomospora indica  in  plant  disease  management. Plant Pathology Science 5(1):48-61.

Piriformospora indica as the one of the most important soil endophytic microorganism, can increase yield of plants per unit area, by modifying the physiological characteristics of the host plants. It also provide the possibility of crop production in saline and arid soils or even in some conditions with biotic and abiotic stresses.  It grants resistance to plant against diseases, through the induction of systemic resistance. Also the fungus can cause an increase in resistance to salinity and drought, through the increase in antioxidant capacity of root cells and levels of resistance proteins in their host plants. In order to adopt organic farming and achieve sustainable agriculture, this fungus can be used as a suitable alternative for chemical fertilizers and pesticides.

Charehgani H. 2016. Application of microarray technology in plant nematology. Plant Pathology Science 5(1):76-89.

During a compatible interaction, root-knot nematodes (Meloidogyne spp.) induce the root cells dedifferentiation into multinucleate feeding cells, known as giant cells. Hyperplasia and hypertrophy of the cells surrounding the head of nematode lead to the formation of a root gall. Different studies showed that the transformation of root cells into hypertrophied feeding structures, with unique morphology and functions, require some changes in the expression of a large number of genes. Previous approaches, based on differential gene expression between healthy and infected plants, analyses of known candidate genes by promoter GUS fusion or in situ hybridization and promoter trap strategies, have resulted in the characterization of about 50 genes of plant that are up regulated and 10 genes that are down regulated in giant cells. Microarray technology makes it possible to generate large-scale information about patterns of gene expression during plant–nematode interactions. A DNA microarray is a collection of microscopic DNA spots attached to a solid surface. Each DNA spot contains 10^−12 moles of a specific DNA sequence, which are known as probes. These can be a short section of a gene or other DNA element that are used to hybridize a cDNA or cRNA sample that called as target. Probe-target hybridization is usually detected by detection of fluorophore or silver labeled targets.

Najafiniya M. 2016. Management of citrus die-back disease. Plant Pathology Science 5(1):26-36.

Citrus trees are very important plants with high economic value and significant cultivation area in south of Iran. During the recent years, citrus die-back disease caused by Neofusicoccum mangiferae became one of the main treats for citrus production in tropical and sub-tropical regions of Iran. The symptoms of die- back disease are including wilting and declining of branches which start from the tip and then develop to down part of the trunk of infected tree, which sometimes has longitudinal cracks with gum exudation. Cortical layers of infected branches are sloughing off and the mass of fungal spores can be observe easily. Based on some investigations, pathogen is inactive during the winter months and its activity starts from spring and terminates at the end of summer season. The disease is more sever when it occurs in the orchards with poor disease management as well as water and nutrient deficiency. Some cultural practices like a well-managed irrigation and enough fertilizing with no pruning during the summer months, are good disease control measures, which in this paper are discussed.

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.

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.

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.

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.

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.

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.

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.

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.

Vasebi Y., Buroon S. and  Faghihi M. M. 2017. Common pathogenic agents of plant and human. Plant Pathology Science 6(2):78-88.

Some plant pathogens are also serious threats to human health. Pathogenic fungi from the genera Alternaria, Aspergillus, Bipolaris, Cladosporium, Claviceps, Fusarium, Paecilomyces and Exserohilum, and some bacteriaa genera including Burkholderia, Enterobacter, Enterococcus, Escherichia, Erwinia, Pantoea, Pseudomonas, Salmonella, Serratia and Xanthomonas can cause harmful diseases in human. Diseases caused by these microorganisms in plants and human are described here and some researches to identify them on raw fruits and vegetables are suggested.