This study used American chestnut (Castanea dentata) and blight resistant hybrid chestnuts inoculated with Pisolithus tinctorius (Pt). The colonization of chestnut roots by ectomycorrhizal fungi (ECM) was assessed to determine if Pt remained the colonizing fungus and if the effects of mechanical soil treatments influenced ECM fungal diversity. Four soil treatments were established on a reclaimed strip mine in Madison County, Ohio: 1) a control plot (C) left undisturbed, 2) soil mechanically ripped (R) to a meter depth, 3) a plowed and disked plot (PD), and 4) a ripped + plowed and disked plot (R+PD). Twelve hundred Pt inoculated chestnut seedlings were planted.
Results/Conclusions

At the end of the growing season, 120 seedlings representing all treatment types were sub-sampled for root evaluation. Of the 120 sampled, 102 (85%) were scored as mycorrhizal and fungal DNA was extracted. Eleven fungal genera were identified by sequencing the ITS region. Interestingly, despite prior inoculation, Pt was not found on chestnut root tips. Hebeloma (35% - 56%) and Thelephora (27 – 47%) were the most abundant ECM genera sampled during this study. Unlike Hebeloma, Thelephora was not found in the control plots. Additionally, Thelephora was found in a greater abundance than Hebeloma in the R+PD plots, 47% and 35%, respectively (P = 0.012). When ECM diversity was assessed, the control plots (0.37) had a lower Simpson’s index when compared to R, PD, and R+PD plots (0.51-0.59). Though not statistically significant (P = 0.64), a trend may exist suggesting greater ECM fungal diversity in mechanically treated plots.