Showing 11 results for Resistance
Zahra Amjadi , Habiballah Hamzehzarghani,
Volume 3, Issue 1 (3-2014)
Abstract
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.
Mohaddeseh Zal, Reza Mostowfizadeh-Ghalamfarsa,
Volume 3, Issue 1 (3-2014)
Abstract
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.
Vahid Rahjoo , Masoumeh Hatamzadeh, Hatamzadeh Mahrokh, Sayyed Mohammad Ali Mofidian,
Volume 3, Issue 1 (3-2014)
Abstract
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.
Mohammad Sherafatifar, Habiballah Hamzehzarghani, Samira Shahbazi,
Volume 3, Issue 2 (9-2014)
Abstract
Food production and food security is an essential precursor to sustainable development in agriculture. Currently, more than 800 million people, generally in Africa and Asia, suffer from hunger and agriculture is considered as the main source of food for them. One of the application of nuclear technology is reducing the damages of plant pest and diseases. The application of nuclear techniques in plant pathology can be grouped in three categories including disease tracing, mutagenesis induction and radiation of crops to induce resistance and destruction of pathogens. As a new method to induce defense responses to biotic and abiotic stresses, nowadays, gamma radiation is used to improve the growth in the way to induce the plant resistance to environmental tensions and plant pathogens as well. Use of this potential, especially in management of seed and seedling diseases is very important to reduce a big portion of crop losses caused by plant pathogens in the first weeks of seedling growth.
Leila Sadeghi, Salar Jamali,
Volume 5, Issue 2 (8-2016)
Abstract
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.
Jalal Gholamnezhad,
Volume 6, Issue 2 (9-2017)
Abstract
Gholamnejad J. 2017. Plants defense mechanisms against pathogens.
Plant Pathology Science 6(2):24-32.
Plants have many defense mechanisms against pathogens that can be stimulated and activated by some microorganisms or chemicals. There are five types of induced resistance in plants that are included: localized acquired resistance, systemic acquired resistance, systemic gene silencing, induced systemic resistance, and systemic wounding response. Systemic acquired resistance is the most important type of induced resistance in plants that result in continuous and prolonged protection from infection against a wide range of pathogens. Formation of pathogenesis related proteins, alteration of cell wall with sedimentation and binding of polysaccharides, proteins, glycol-proteins, phenols, phytotoxins, and ligninification are the stages of occurrence of this type of resistance in plants.
Zabihollah Azami-Sardooei, Farnaz Fekrat, Fataneh Ghalavand,
Volume 6, Issue 2 (9-2017)
Abstract
Azami-Sardouei Z., Fekrat F. and Ghalavand F. 2017. A review on the application of benzothiadiazole in plant diseases management. Plant Pathology Science 6(2):33-42.
The use of plant defense activators is a novel method of plant diseases management in recent years. Benzothiadiazole (BTH), is the first synthetic plant defense activator. In general, Benzothiadiazole has no direct effect against the pathogens, but it can activate the systemic acquired resistance (SAR) in plants, against a number of plant diseases. In addition, BTH widely is used to protect the plants against a range of pathogens on wheat, tomato, bean, tobacco, lettuce, banana and pears. In overall, Benzothiadiazole can be used as a safe and reliable product for plant protection and also as an alternative for chemical pesticides, which they have hazardous effects on environment.
Aminallah Tahmasebi, Mohamad Hamed Ghodoum Parizipour,
Volume 9, Issue 1 (3-2020)
Abstract
Tahmasebi A, GhodoumParizipour MH (2020) The role of brassinosteroid hormones in plant response to pathogens. Plant Pathology Science 9(1):108-117. DOI: 10.2982/PPS.9.1.108.
Plants are usually attacked by several pathogens. Different defense pathways in plants have evolved in reaction to pathogens. Plant defense responses have been shown to be regulated by various plant hormones. Brassinosteroids are plant-specific steroid hormones that play important roles in regulating growth and developmental processes. In addition to acting as a regulator of plant growth, they also play a role in defense responses to pathogens. Many researches have been done on their role in plant resistance to fungi, bacteria and viruses, which are described in this article. Further understanding of the role of these hormones in plant defense responses can be useful in inducing resistance or producing plants resistant to pathogens.
Aminallah Tahmasebi,
Volume 10, Issue 1 (2-2021)
Abstract
Tahmasebi A (2021) The role of ubiquitin in plant-virus interactions. Plant Pathology Science 10(1):141-152. Doi: 10.2982/PPS.10.1.141.
Plant viruses cause major losses to agricultural crops worldwide. Plants react to the virus infections via several defense mechanisms, such as ubiquitination. Ubiquitin (Ub) and ubiquitin proteasome system (UPS) play key role in the function modification and degradation of proteins in plants. Ub attachment to the cellular proteins alters the stability, the cellular establishment or activity of the target protein. The key role of UPS has been revealed in defense mechanisms and other plant processes. Viruses as obligate intracellular parasites have evolved mechanisms to interfere UPS. In some cases, it has been shown that viral proteins were targeted by this system. Ubiquitination plays an important role in plant–virus interaction which can lead to plant resistance or pathogenicity in the host plant. Therefore, further understanding of UPS and its role in plant-virus interaction can develop novel methods to increase resistance to viral infections in plants.
Samaneh Bahlooli, Masoud Abrinbana, Youbert Ghosta,
Volume 10, Issue 2 (9-2021)
Abstract
Bahlooli S, Abrinbana M, Ghosta Y (2021) The effect of the mixtures of carbendazim, iprodione and tebuconazole on Sclerotinia sclerotiorum. Plant Pathology Science 10(2):40-49. Doi: 10.2982/PPS.10.2.40.
Introduction: Soil-borne fungus Sclerotinia sclerotiorum or white mold is the cause of the destructive disease of root and stem rot of many plants. Chemical control due to the lack of highly resistant cultivars is the most important method in the pathogen management program in various plants. However, the repeated use of fungicides leads to the development of resistant strains in pathogen populations. The use of fungicides with different modes of action, especially those with a synergistic effect, is one the most important anti-resistance methods. Materials and Methods: In this research, the effect of different mixing ratios in pairs of carbendazim, iprodione, and tebuconazole fungicides and their possible synergistic activity on four S. sclerotiorum isolates were investigated in vitro conditions. For this purpose, the isolates were cultured on potato dextrose agar, containing different concentrations of fungicides mixtures, and EC50 values and the synergy factors were then determined for different mixtures ratios. Results: Tebuconazole: carbendazim mixture in 1:7 ratio, with a synergistic activity, inhibited all the isolates growth, and carbendazim: iprodione mixture in 1:9 ratio showed a synergistic effect on three isolates. Conclusion: The mixture of tabuconazole: carbendazim in 1:7 ratio had the best synergistic activity, and inhibitory effect on the growth of all the pathogen isolates, so it has the potential to be used in the management program of S. sclerotiorum.
Aminallah Tahmasebi,
Volume 12, Issue 1 (3-2023)
Abstract
Tahmasebi, A. (2023). The role of translation initiation factors in plants recessive resistance to viruses. Plant Pathology Science, 12(1), 113-121.
Abstract
Plant viruses are important pathogens that cause quantitative and qualitative decline of agricultural products all over the world. Plants resistance is the most effective way to control plant viruses. Viruses as obligate parasites to complete their infection cycle, such as the processes of protein synthesis, replication, and movement, are dependent on the compatibility of cellular factors of host plants. Absence or mutation in these essential factors for the virus infection cycle or mutation in the regulator of plant defense responses may cause the host's recessive resistance to the virus. Recessive genes identified in virus-plant interactions include eukaryotic translation initiation factors eIF4E, eIF4G, and their isoforms. A number of translation factors have been identified in plants, such as eIF3, eEF1A, and eEF1B, which are essential in interacting with viral RNAs and regulating various processes in the virus infection cycle. More awareness of molecular mechanisms of these factors as well as their interaction with other host and viral factors can be used in the development of new management methods such as silencing or genome editing against viruses.
