Development of strain-specific primers for a strain of Gliocladium catenulatum used in biological control

The randomly amplified polymorphic DNA (RAPD) technique was used to develop strain-specific primers for Gliocladium catenulatum strain J1446, which is promising in biological control. One of the primer pairs developed proved to be strain-specific; strain J1446 was differentiated from 16 G. catenulat um strains and six other strains of two Gliocladium species, as well as fro m Trichoderma virens, and isolates of Nectria spp. and Fusarium spp. Specif ic primers were also tested with DNA isolated from cucumber leaves, treated or untreated with a solution made from Gliocladium powder. The expected am plification product was produced only from treated leaves. DNA isolated fro m Gliocladium-treated potato tubers and fungi grown in peat was also used i n amplification reactions. Strain-specific primers detected strain J1446 wh en the amount of DNA was 5 pg or more. Some variation between the Gliocladi um strains was found by the random amplified microsatellites method (RAMS) and the universally primed polymerase chain reaction method (UP-PCR), but n o clear fragments specific to strain J1446 were produced. Cross-blot hybrid isation of UP-PCR products differentiated strain J1446 from T. virens, but not from the Gliocladium isolates. The 28S rDNA sequences and beta-tubulin sequences were identical or very similar in all Gliocladium strains. Thus, it is possible that the Gliocladium strains of the present study are conspe cific, which means that a revision in the taxonomy of Gliocladium species m ay be necessary.