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عنوان فارسی مقاله:
روش تقسیم آگار از متابولیت های میکروبی خاک ضد قارچ
عنوان انگلیسی مقاله:
Split-agar assay of antifungal soil microbial metabolites
سال انتشار : 2016
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مقدمه انگلیسی مقاله:
1. Introduction
Sustainable development requires us to maintain soils in a productive and healthy state. Global efforts have been underway for long to devise various tests for the physical, chemical and biological indicators of soil quality. While the first two are fairly standardized, the concept and methods of a soil biological test have remained as a complex goal. Various fractions of soil organic matter, microbial biomass, soil respiration and soil enzymatic tests have been proposed and tested as indicators of soil biological quality but till date there is no easy test that can be used for assaying soil health, for example ability of soil to suppress plant diseases. There is thus a need for a simple method to quantify the anti-fungal antibiosis potential of soils to assay soil suppressiveness quantitatively. Soils vary in their inherent ability to inhibit the growth of pathogenic fungi (Alabouvette, 1986). This ability is influenced by many abiotic (pH, nitrogen content, etc.,) and biotic (composition of soil microbiota) factors, the latter being more influential (Bonilla et al. 2012). Soil microflora suppress fungal pathogens through a variety of mechanisms like competitive exclusion, antagonism and induction of host plant defense mechanisms (Mazzola, 2002). Antagonism has been most investigated since the population of antagonists can be built up in soils to improve soil suppressiveness. Antagonism to phytopathogenic fungi is usually improved by inoculating microorganisms producing antifungal metabolites (Mazzola, 2007). Strategies adopted by microorganisms to overcome competition in natural (soil) or artificial (culture media) ecosystems include production of antimicrobial compounds, higher growth rates, higher affinity for essential nutrients (e.g., iron binding by siderophore production) among others. Of these, antibiosis has been the most routinely used assay. A classical method of studying antibiosis in soils is the crowded plate technique (Cappuccino and Sherman, 2008) where antagonists are obtained by inducing competition among soil microbes. This method has been adapted and modified by Rupela et al. (2003) to obtain fungal antagonists from soil. Although such methods are very useful to screen for antagonists in soil, but they are not suitable for quantification purpose as the clearing zones are counted without taking into consideration their diameter. This makes comparative assessments of soil suppressiveness difficult. Quantification of antagonists may be achieved by extracting the antifungal metabolites from soils and analysis by gas chromatography or HPLC (Chuankun et al. 2004), but this requires more time and expertise and is not useful to quantify unknown metabolites. For routine assays, there is a need for a simple method to quantify the antifungal antibiosis potential of soils. We report the development of a method to quantify the potential to elaborate anti-fungal metabolites by various soils when inoculated and incubated in culture broths. The principle is similar to crowded plate but the competition is induced here in broth than in petri plates and the anti-fungal activity is quantifiable. Soil-water extracts have very low amount of antifungal compounds and large amounts would need to be vacuum concentrated to reduce the volumes for theassay. To overcome this, the potential antimicrobial production by antagonists was amplified by incubation in broth. Secondly, soil suspensions only show up the amount of antimicrobials produced until the point of sampling but the actual potential of the soil to produce antifungal compounds can be known only by an incubation assay.
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کلمات کلیدی:
Production of fungal and bacterial growth modulating secondary ... www.biomedcentral.com/content/pdf/1471-2180-12-164.pdf by SD Schrey - 2012 - Cited by 28 - Related articles Aug 2, 2012 - into the co-existence mechanisms of soil bacteria and fungi is crucial in ..... The identified metabolites included antifungal and anti- microbial ... Biological Fixation of Nitrogen for Ecology and Sustainable Agriculture https://books.google.com/books?isbn=3642591124 Andrzej Legocki, Hermann Bothe, Alfred Puehler - 2013 - Science Enhancing the potential of microbial inoculants through molecular microbial ... exhibit antifungal activities against a number of soil-borne fungal pathogens ... of antifungal secondary metabolites including phenazines and phloroglucinols (3,7,9 ... Frontiers | Diversity and functions of volatile organic compounds ... journal.frontiersin.org/article/10.3389/fmicb.2015.01081/full by V Cordovez - 2015 - Cited by 14 - Related articles Sep 22, 2015 - In disease-suppressive soils, plants are protected from infections by specific root ... large number of secondary metabolites, including volatile organic ... on fungal growth, pointed to VOCs potentially involved in antifungal activity. Fungal Biotechnology in Agricultural, Food, and Environmental ... https://books.google.com/books?isbn=0824747704 Dilip K. Arora - 2003 - Science The strain was isolated from cave soil in Korea by an extensive screening program for ... Most of their metabolites, therefore, were not subjected to the antifungal ... Technology Transfer of Plant Biotechnology https://books.google.com/books?isbn=0849382653 Peter M. Gresshoff - 1996 - Science Antifungal. Metabolites. in. Biological. Control. of. Plant. Disease. Steven Hill, Philip E. ... This has led to the discovery and study of many soil microbes that are ... Searches related to antifungal soil microbial metabolites antifungal activity of bacteria antifungal bacteria
