ISSN:
1365-3059
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Isolates of the take-all fungus, Gaeumannomyces graminis var. avenae, which affects oats, wheat and other grasses, and of G.g. var. tritici, which preferentially affects wheat, rye and barley, contain a high proportion of repeated sequences. Total DNA from 57 fungal isolates collected from many locations and different cereal hosts, and scored for virulence on wheat, rye and oats, revealed many restriction fragment length polymorphisms. These RFLPs were observed either by staining the DNA directly, by hybridization to radioactively labelled total fungal DNA, or by hybridization with labelled wheat ribosomal DNA. With only a few exceptions, the isolates with the same preferred cereal hosts showed more similar patterns of restriction fragments than isolates that had different pathogenicity properties on cereal hosts, irrespective of the geographical origins of the isolates. This was even the case for R isolates of G.g. var. tritici that were virulent on wheat and rye compared with N isolates that were virulent only on wheat. Isolates were identified by hybridizing DNA from infected root samples with 32P-labelled total fungal DNA. The restriction fragment polymorphisms involving families of repeated sequence can therefore be used as a predictive assay for host preference of an isolate, and have probably arisen by host selection of fungal lineages. The variation between isolates in different pathogenicity groups suggests that there is little gene flow between isolates that can infect different hosts, even though they can coexist in the same field.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-3059.1992.tb02453.x
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