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 gr aminis var. tritici, in soil. Amplification of G. graminis-specific pr oducts in a PCR assay was correlated with levels of take-all disease i n a range of naturally infested soils. The fungus was detected in soil s that had a moderate to high level of disease (21-66% of seminal root s 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 tak e-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.