Detection and molecular identification protocols for Phyllosticta citricarpa from citrus matter

South African Journal of Science

 
 
Field Value
 
Title Detection and molecular identification protocols for Phyllosticta citricarpa from citrus matter
 
Creator Meyer, Linda Jacobs, René Kotzé, Jan M. Truter, Mariette Korsten, Lise
 
Subject Plant Pathology; Diagnostics; Sanitary and Phytosanitary Phyllosticta capitalensis; diagnostics; citrus black spot; techniques; spore trap; sanitary; phytosanitary
Description Strict quarantine measures for the export of South African citrus fruit to European and US markets require the development of sensitive and accurate detection methods for the pathogen Phyllosticta citricarpa – a fungus causing citrus black spot disease. Because of the presence of other, non-pathogenic Phyllosticta species, rapid and accurate verification of the Phyllosticta species present on exported citrus fruit is important to producers, exporters and regulatory authorities to prevent unnecessary losses. We have analysed over 800 samples collected over 7 years and have compared sample preparation and detection protocols applied in different environments: nurseries, production systems including phytosanitary inspections in orchards, pack houses and export terminals in order to compile protocols for the detection of P. citricarpa. Standard procedures of sample preparation and DNA extraction were adapted to suit diverse inoculum sources. Low pathogen numbers in symptomless green leaves, for example, obliged the use of a wet-dry enrichment technique constituting the stimulation of fungal growth for easier detection. Physical maceration was adapted for sturdy material using liquid nitrogen or bead beating. The use of a two-step polymerase chain reaction (PCR) with nested primers significantly increased both the sensitivity and the specificity of the PCR performed on soil samples, overcoming problems with relatively impure DNA extracts and low pathogen numbers. The assays have proven to be highly consistent, thereby providing a reliable, reproducible and highly sensitive detection and diagnostic service to the southern African citrus industries in order to sustain market access.
 
Publisher AOSIS
 
Contributor Citrus Research International (CRI) and Technology and Human Resources for Industry program (THRIP), funded by the Department of Trade and Industry and managed by the National Research Foundation
Date 2012-03-06
 
Type info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion — —
Format application/pdf text/html application/epub+zip text/xml
Identifier 10.4102/sajs.v108i3/4.602
 
Source South African Journal of Science; Vol 108, No 3/4 (2012); 6 pages 1996-7489 0038-2353
 
Language eng
 
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https://journals.sajs.aosis.co.za/index.php/sajs/article/view/602/1083 https://journals.sajs.aosis.co.za/index.php/sajs/article/view/602/1084 https://journals.sajs.aosis.co.za/index.php/sajs/article/view/602/1091 https://journals.sajs.aosis.co.za/index.php/sajs/article/view/602/1088 https://journals.sajs.aosis.co.za/index.php/sajs/article/downloadSuppFile/602/3338 https://journals.sajs.aosis.co.za/index.php/sajs/article/downloadSuppFile/602/3339 https://journals.sajs.aosis.co.za/index.php/sajs/article/downloadSuppFile/602/3340 https://journals.sajs.aosis.co.za/index.php/sajs/article/downloadSuppFile/602/3341
 
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Rights Copyright (c) 2012 Linda Meyer, René Jacobs, Jan M. Kotzé, Mariette Truter, Lise Korsten https://creativecommons.org/licenses/by/4.0
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