The interactive effects of elevated ozone and wheat cultivars on soil microbial community composition and metabolic diversity

Human-induced global changes have important impacts on terrestrial ecosystems. Although aboveground influences of elevated ozone have been widely studied, relatively little attention has been paid to the belowground subsystem, nevertheless it is critical to study belowground effects in determining the long-term consequences of ozone exposure to ecosystems. Here, we investigated the effects of elevated ozone on soil microbial community structure and functional diversity using the free-air ozone enrichment platform (FAOE). We detected that soil fungal phospholipid fatty acid and the fungal/bacterial ratio were significantly ower under elevated ozone than under ambient ozone at the wheat ripening stage. Through determining soil microbial metabolic diversity as evaluated by variations in the microbial utilization rates of different carbon sources among different wheat cultivars, we found that soil microbial communities inhabiting the rhizosphere of ozone-tolerant cultivars preferred to consume easily degradable carbon sources, while more complex carbon sources were preferably utilized by those associated with ozone-sensitive cultivars. These changes may in turn promote (ozone-tolerant wheat cultivars)/inhibit (ozone-sensitive wheat cultivars) plant growth through alterations in nutrient availability and resource distribution.