SPECIFIC DETECTION OF GAEUMANNOMYCES-GRAMINIS IN SOIL USING POLYMERASE CHAIN-REACTION

The polymerase chain reaction (PCR) was used to detect the presence of the fungus that causes take-all disease of cereals, Gaeumannomyces graminis var. tritici, in soil. Amplification of G. graminis-specific products in a PCR assay was correlated with levels of take-all disease in a range of naturally infested soils. The fungus was detected in soils that had a moderate to high level of disease (21-66% of seminal roots infected). The PCR assay distinguished G. graminis from a wide range of other soil fungi and was useful in detecting G. graminis on wheat roots with low to high (7-85% of seminal roots infected) levels of take-all symptoms. The techniques described in this paper are useful for detecting the take-all fungus in soil and could easily be extended to the detection of other soil fungi.