Bacillus-specific DGGE fingerprint of tuber surface samples generated with four independent repetitions of the commercial cultivars ‘Baltica’, ‘Selma’, ‘Désirée’, ‘Ditta’ and ‘Sibu’ and the two GM lines SR47 and SR48 grown at the field trial in Oberviehhausen. S, bacterial standard; AS, standard generated with in vitro antagonistic strains obtained from the tuber surface. [(a and b) Bacillus pumilus, (c) Bacillus subtilis)].