Comparison of Soil Fungal Community Structure in Different Peanut Rotation Sequences Using Ribosomal Intergenic Spacer Analysis in Relation to Aflatoxin-Producing Fungi

    Sudini, H and Arias, C R and Liles, M R and Bowen, K L and Huettel, R N (2011) Comparison of Soil Fungal Community Structure in Different Peanut Rotation Sequences Using Ribosomal Intergenic Spacer Analysis in Relation to Aflatoxin-Producing Fungi. Phytopathology , 101 (1). pp. 52-57. ISSN 0031-949X

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    Abstract

    The present study focuses on determining soil fungal community structure in different peanut-cropping sequences by using a high-resolution DNA fingerprinting technique: ribosomal intergenic spacer analysis (RISA). This study was initiated to determine fungal community profiles in four peanut-cropping sequences (continuous peanut, 4 years of continuous bahiagrass followed by peanut, peanut-corn-cotton, and peanut-cotton rotations), with a special focus to evaluate whether the profiles under investigation may have also indicated microbial differences that could affect Aspergillus flavus populations. Results indicated 75% similarities among fungal communities from the same cropping sequences as well as with similar times of sampling. Polymerase chain reaction (PCR)-based detection of A. flavus directly from these soils was carried out using A. flavus-specific primers (FLA1 and FLA2) and also through quantitative estimation on A. flavus and A. parasiticus agar medium. Population levels of A. flavus in soil samples ranged from zero to 1.2 × 103 CFU g–1 of soil (based on culturable methods); however, the fungus was not detected with A. flavus-specific primers. The minimum threshold limit at which these aflatoxin-producing fungi could be detected from the total soil genomic DNA was determined through artificial inoculation of samples with 10-fold increases in concentrations. The results indicated that a minimum population density of 2.6 × 106 CFU g–1 of soil is required for PCR detection in our conditions. These results are useful in further determining the relative population levels of these fungi in peanut soils with other soil fungi. This is a new approach to understanding soil fungal communities and how they might change over time and under different rotation systems.

    Item Type: Article
    Divisions: UNSPECIFIED
    CRP: UNSPECIFIED
    Subjects: Mandate crops > Groundnut
    Others > Soil Science
    Others > Entomology
    Depositing User: Mr Sanat Kumar Behera
    Date Deposited: 11 Jan 2012 04:53
    Last Modified: 11 Jan 2012 04:53
    URI: http://oar.icrisat.org/id/eprint/5330
    Official URL: http://dx.doi.org/10.1094/PHYTO-03-10-0072
    Projects: UNSPECIFIED
    Funders: UNSPECIFIED
    Acknowledgement: UNSPECIFIED
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