Fungal and Bacterial Communities Associated With Biofuel Crops.

Understanding how the cultivation of biofuel crops impacts microbial soil communities is key to successfully managing the sustainability of these agricultural systems.  Bacterial and fungal communities at northern grassland sites in Michigan and Wisconsin were characterized before and 3 seasons after planting with poplar and willow, and these sites were contrasted with southern sites in each state under corn, switchgrass and prairie.  Both 16S (bacteria) and 28S (fungal) rRNA gene sequence data partitioned samples into three main groups, southern sites, northern Michigan and northern Wisconsin sites, most likely because of differences in climate and land use history.  Northern and southern sites were each distinguished by unique taxa.  Additionally, after planting, both types of data differentiated the northern communities in both states by crops, but the fungal sequence data gave more distinctive results.  Compared to grass sites (pre-planting and control), sites under willow had higher proportions of sequences from Hebeloma, characteristically associated with both hardwoods and conifers, and several members of the order Peziales that decompose wood.  The poplar sites tended to have higher proportions of sequences for fungi associated with decomposition of leaf litter, such as Phaedothis, Phaeosphaeria, Paraphaesphaeria and members of the orders Hypocreales and Pleosporales. While most taxa are common among sites and crops, a few are selected by the climate and crop sufficient to differentiate the communities.