ISHS Acta Horticulturae 482: International Symposium on Cut Flowers in the Tropics
DETECTION OF PLANT PATHOGENS IN FLOWERS BY THE PCR TECHNIQUE |
| Authors: | S. Manulis, N. Kogan, L. Valinsky, O. Dror, F. Kleitman |
| Keywords: | Erwinia herbicola pv. gypsophilae, Fusarium oxysporum f. sp. dianthi, Gypsophila paniculata, carnation |
| DOI: | 10.17660/ActaHortic.1999.482.17 |
| Abstract:
In ornamentals the use of culture indexing to obtain disease-free propagation material is crucial, therefore sensitive, rapid and reliable methods are necessary. Two example of using the PCR method for detection of plant pathogens causing diseases in flowers will be presented. The first is the disease caused by the bacterium Erwinia herbicola pv. gypsophilae. This is the most destructive pathogen of Gypsophila paniculata, an ornamental used for cut flower production. The pathogen induces gall formation at wound sites. Three primer pairs, based on the sequence of the phytohormones biosynthetic genes were used for detecting the pathogen in Gypsophila plants by the polymerase chain reaction (PCR). The primers were specific to all gall-forming E. herbicola strains and distinguished them from saprophytic strains associated with gypsophila plants or from other gall-forming bacteria. By nested-PCR or Bio-PCR the bacteria could be detected in symptomless gypsophila cuttings. The procedure we describe in this study could be used for establishing disease-free stock of mother plants of gypsophila. The second example is the wilt disease of carnation caused by the fungus Fusarium oxysporum f. sp. dianthi. This disease is considered a major limiting factor in all areas of carnation production. By using the random amplified polymorphic DNA (RAPD) method it was possible to distinguish among pathogenic and non-pathogenic isolates of Fusarium oxysporum recovered from carnation. Over hundred isolates were recovered from 39 different cultivars of carnation and from 25 different locations in Israel. Most of the isolates were classified as race 2. The isolates were examined for RAPD patterns with 30 arbitrary primers of 10 bases. The RAPD patterns generated by each of 22 primers enabled us to distinguish clearly between pathogenic and non-pathogenic isolates from carnation. | |
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