Variability in pathotype, aggressiveness, RAPD profile, and rDNA ITS1 sequences of UK isolates of Rhynchosporium secalis
Authors: Newton, A.C., Searle, J., Guy, D.C., Hackett, C.A. and Cooke, D.E.L.
Journal: Zeitschrift fur Pflanzenkrankheiten und Pflanzenschutz
Volume: 108
Issue: 5
Pages: 446-458
ISSN: 0340-8159
Abstract:A local population of Rhynchosporium secalis was sampled and the race structure, pathogenicity, RAPD profile and rDNA ITS sequence examined. RAPDs were also used to compare this population with a larger sample of isolates including some isolated more than 30 years ago. Both the local population and the wide sample revealed much variation for all characteristics with no two isolates identical. The reliability of detached leaf pathogenicity tests was improved over previous studies by pre-washing spores and brushing the leaves prior to inoculation. Isolate aggressiveness was highly correlated with lesion number but not lesion size. There was no correlation between race and aggressiveness. RAPD profiles showed high levels of variability but more similarity was observed within a site than between sites. Clusters of similarity were primarily associated with samples from the same locality but samples taken 8 years apart from within the same field were not closely related. ITS2 sequences were all identical whereas ITS1 sequences showed 0.8 % polymorphism. ITS polymorphisms fell mostly within one RAPD cluster. ITS sequence comparisons with the EMBL database gave some indications of the taxonomic placement of R. secalis.
Source: Scopus