http://yujs.yu.ac.ir/pps University of Yasouj Plant Pathology Science - Journal articles for year 2014, Volume 3, Number 1 Yektaweb Collection - https://yektaweb.com en 2014/3/10 http://yujs.yu.ac.ir/pps/browse.php?a_id=56&sid=1&slc_lang=en Metabolomics or analysis of all cellular metabolites is a new and powerful tool that provides possible quick view to the large number of small molecules (metabolites) within the cell and indicates dynamics of these molecules under different conditions. Quantitative and qualitative measurements of large number of cellular metabolites provide a broad view of the biochemical status of an organism that can be used to monitor and assess gene function. Today, metabolomics is widely being used in agriculture for classification of plants, studying phytochemical diversity of medicinal plants, assessment of the changes which occur in the biochemical composition of foods occurring, for example, during the pasteurization of Basmati rice for long-term storage or the boiling for direct consumption. In plant pathology, metabolomics has been mainly used to study plant responses to a wide range of biotic or abiotic stresses including resistance of plants to pathogens and also as a powerful tool for functional genomics studies. Profiling of the transcriptome and proteome has received some criticism due to their inability to predict gene function but profiling of the metabolites is promising as it provides instantaneous large amounts of data from cell physiology. Study of plant genetic resistance is one of the most important applications of metabolomics. Since metabolites are final products of gene expression and all changes in gene expression is reflected in metabolite profiles, hence metabolite profiles produce a more comprehensive understanding of plant defense mechanisms against stresses such as pathogen challenge. On the other hand, breeders are looking for rapid, simple and accurate tools for identifying metabolites associated with resistance as biomarker for screening cultivars resistant to diseases. In addition, understanding resistance mechanisms at the level of metabolome may help breeders for better understanding of resistant gene function and pyramiding suitable resistant gene in elite cultivar. This article is a review of the science, its applications in plant pathology, methods of study metabolites and their administrative problems. HABIBALLAH HAMZEHZARGHANI http://yujs.yu.ac.ir/pps/browse.php?a_id=57&sid=1&slc_lang=en Plant diseases are the most important limiting factors in agricultural production. Currently the major control method of plant diseases is based on the use of chemicals that raises serious concerns about food quality, environmental hazards and development of resistance to agrochemicals. These concerns have increased the need for other alternative disease management techniques. Macro- and micronutrients are normally applied to increase crop production and improve general plant health and quality. They can also increase the disease tolerance or resistance of plants, however there are some opposing reports. Although our knowledge on the impact of mineral nutrients on plant diseases, many other factors that control plant's response and dynamic interactions among plant, environment and pathogen is not sufficient, manipulating soil nutrients through amendment or modification is always an essential part in plant disease control as well as in sustainable agriculture. Mineral nutrients are generally the first and the most important line of defense against plant diseases which affect all parts of the disease triangle. Nutrients can satisfactory decrease diseases, or at least diminish them to a level at which additional control measures are more successful and less expensive. Here we review the most recent data regarding the influence of mineral nutrients on plant disease resistance and tolerance, plant histological or morphological structure and the virulence or capability of pathogens to survive. MOHAMMAD REZA MOOSAVI http://yujs.yu.ac.ir/pps/browse.php?a_id=58&sid=1&slc_lang=en Development of human civilization is closely associated with agricultural crops. The major threat to crops posed by fungal diseases results in the use by growers of enormous amounts of chemicals. Fungicides are compounds, which are toxic to fungi. These materials have been applied for a long time to reduce losses and increase the quality and yield of the agricultural products. Today in addition to improving the quality and quantity of agricultural products and protecting plants by fungicides, the fungicide resistance problem must also be considered. The appearance of resistance has an important factor in limiting the efficacy and useful lifetime of fungicides. In general, systemic fungicides have been associated with resistance problems to a much greater extent than have non-systemic (protectant) fungicides. However, there are some exceptions. This paper discusses the resistance mechanisms to fungicides of some phytopathogenic fungi (e.g. altered target site, reduced uptake of fungicide, removal, detoxification or metabolism of fungicide) at the molecular level and describes methods used in the molecular detection of fungal resistance (e.g. RFLP-PCR, and allele specific real-time PCR) to fungicides. REZA MOSTOWFIZADEH-GHALAMFARSA http://yujs.yu.ac.ir/pps/browse.php?a_id=59&sid=1&slc_lang=en Alfalfa downy mildew caused by Peronospora trifoliorum de Bary, is one of the factors decreases alfalfa yield. It distributes as epidemic and causes falling and yellowing the leaves in favorite conditions especially in spring and first cutting of alfalfa. In order to select alfalfa resistant ecotypes to downy mildew disease, standard greenhouse and field experiments can be used. In greenhouse tests 7-day-old seedlings are inoculated with spore suspension and after incubation period, the percentage of the symptomless seedlings is compared with resistant control as soon as disease symptoms appear. Field experiments are carried out with minimum three replications of alfalfa ecotypes in an appropriate statistical design at some locations in which natural condition for disease occurrence exists. A susceptible ecotype is used as spreader in order to help disease distribution. Resistance of ecotypes is evaluated based on percentage of the leaves infection in five different classes (1-5) scoring system. Nowadays large number of researches has been done on alfalfa resistance to downy mildew and several resistant cultivars have been reported worldwide. For example KS224 and Saranac have been known as resistant cultivars to downy mildew. Some cultivars and ecotypes such as Kiseverdai, Nikshahri, Gharghlooogh and Malek-Kandi show good tolerance to disease in a few researches carried out in Iran. Results of field and greenhouse experiments are relative similar and show good correlation. It seems that using these ecotypes in different regions of Iran especially cold regions in which disease is frequently observed and considering other management methods such as appropriate cutting can be considerably decrease the occurrence of the disease and the crop loss. VAHID RAHJOO http://yujs.yu.ac.ir/pps/browse.php?a_id=60&sid=1&slc_lang=en Yellow rust is a major disease of wheat in Iran. Airborne spores fungal pathogen are the primary source of contamination. Temperature, humidity, wind intensity and direction, reaction of growing cultivars to the disease, presence of wheat in summer, planting time and nutritional status of wheat are effective factors in epidemy of the disease. The importance of the disease in the world, symptoms of the disease , effective factors in disease spread, forecasting model and its administrative procedures, and suitable fungicides to control the disease have been described . Mehdi Sadravi http://yujs.yu.ac.ir/pps/browse.php?a_id=61&sid=1&slc_lang=en Salicylic acid is a kind of phenolic acids and a derivate of salicylate hormone that produced in plants in response to the large numbers of plant pathogens and is necessary for inducing systemic acquired resistance. Vast numbers of studies have done by researchers on the salicylic acid function in inducing plant resistance genes specially those that are responsible for pathogenesis related protein encoding. Results indicated to the effective role of this hormone in inducing innate resistance against pathogenic agents in plants. Changes that block the salicylic acid production in plants increase the disease susceptibility to plant pathogens. Transcription factors belonging to the WRKY, TGA and MYB families are involve in salicylic acid dependent resistance to plant pathogenic agents. Salicylic acid induces the pathogenesis related proteins through the NPR1 dependent pathway during hypersensitive response and systemic acquired resistance reactions. Signaling pathway, independent from NPR1 is a different form of salicylic acid dependent signal transduction and is require for specific resistance against pathogens. Salicylic can also induce the RNA-Dependent-RNA Polymerase gene expressions and play an important role in RNA silencing. Totally, with having knowledge about the salicylic acid biology and its signal transduction pathways in plants it is possible to increase the crop yields with increasing the resistances potential to stresses. ATHAR ALISHIRI http://yujs.yu.ac.ir/pps/browse.php?a_id=62&sid=1&slc_lang=en Most of the symbiotic fungi can improve the growth of the host plants by increasing in water and nutrients absorption. Among the symbiotic fungi, Piriformospora indica or Piri have a good potential in symbiotic relation with plants and well known for its effect on host plants by increasing adventitious roots and growth stimulation in above and below ground parts of the plants. The effects of this fungus on vegetative growth of some medicinal plants and accumulation of the secondary metabolites have been discussed. AMINALLAH BAGHERIFARD