Metagenome analysis of 6 weeks old wheat root-associated bacteria as influenced by CO2 and nitrate levels

Elevated CO2 (eCO2) stimulates plant growth and photosynthesis, which affect root deposition. Combined with nitrate supply, these lead to altered structure and function of the root microbiome. We studied the interactions between eCO2 and nitrate supply at different levels, on wheat-root microbiome structure and function, with an emphasis on denitrifying communities. Wheat plants were grown in a greenhouse under ambient CO2 (400 ppm) or eCO2 (850 ppm). The total bacterial community was quantified using qPCR with universal 16S RNA gene primers, and denitrifying genes (nirK, nirS, nosZ) levels were quantified. In addition, total microbial community function and composition in roots were analyzed by shotgun sequencing (metagenome).