Figure 6

Contamination checking: PCR markers for fungi and bacteria in DNA isolated by the enzymatic method. Lines 1 to 12: Internal transcribed spacer (ITS) of ribosomal DNA amplified with eukaryotic specific universal primers ITS1 and ITS4 [17]. Lines 13 to 20: 16S ribosomal DNA amplified with prokaryotic specific universal primers 9f and 1429r [18]. Amplifications from respectively 10, 1, 0.1 and 0.01 pg of genomic DNA of Trichoderma longibrachiatum (lines 1 to 4), Ilex aquifolium (lines 5 to 8) and Artrospira sp. (lines 13 to 16). Amplifications of DNA isolated from a digestion mix alone (lines 9 and 17), a digestion mix "contaminated" with an Ilex aquifolium leaf disk removed after 10 min and further incubated overnight at 50°C (lines 10 and 18) and a mix digesting an Ilex aquifolium leaf disk overnight at 50°C (lines 11 and 19). Line 12 and 20: negative controls.