Effects of prescribed burning on mycorrhizal fungal diversity of two and a half-year old planted black spruce (Picea mariana) seedlings: Molecular characterization of ectomycorrhizal fungi using PCR/RFLP analysis.

BALDWIN, QUENTIN F.¹ & KEITH. N. EGGER².

¹Biology Department, Memorial University of Newfoundland, St. John's, NF, A1B 3X9, CANADA, ²Natural Resources & Environmental Studies, University of Northern British Columbia, Prince George, BC, V2N 4Z9, CANADA.

Out-planted spruce seedlings were harvested from prescribed burned plots to assess the effects of fire intensity on ectomycorrhizal fungal diversity. PCR, using universal and fungal specific primers, was used to amplify the ITS region and part of the 28S gene of the rDNA. RFLP analysis of the PCR fragment was used to identify molecular types. Tips with distinct mantles produced more consistent RFLP patterns compared to non-mantled tips, or those with thin or patchy mantles. The latter group was removed from the analysis because they displayed a wide variety of RFLP variants, even where a mantle was not present, suggesting that root endophytic fungi were being amplified. Mantled tips tended to produce distinct, although often polymorphic, RFLP patterns, corresponding roughly to morphotypes. Diversity among replicate treatments was high, and sharing of variants did not occur at a high frequency. To date, only nine cases have been found where molecular variants with the same RFLP patterns were shared between treatments, and only three of these cases were variants from different `morphotypes'. Burn intensity had no significant effect on the molecular diversity of mantled tips using Shannon-Wiener and Simpson diversity indices.