Effects of Elevated CO2 on Tomato (Lycopersicon esculentum Mill.) Growth and Rhizosphere Soil Microbial Community Structure and Functionality

Although elevated CO2 (eCO(2)) in the atmosphere is one of the main factors influencing climate and ecosystem stability, less research on eCO(2) in greenhouse soil systems has been conducted, despite their prevalence. In this article, phospholipid fatty acid (PLFA) profiling, 16S rRNA and Internally Transcribed Spacer (ITS) gene sequencing and high-throughput quantity polymerase chain reactions (HT-qPCRs) for 72 biogeochemical cycling-related genes were used to reveal the comprehensive responses of microbes to 23 days eCO(2) fumigation in the soil of a tomato greenhouse. Our results indicated that eCO(2) significantly increased microbial biomass (p < 0.05). The fungal community was more susceptible to eCO(2) than the bacterial community; the fungal alpha diversity indices decreased significantly under eCO(2) (p < 0.05) and the abundance of Ascomycota and its lower level taxa also increased significantly (p < 0.01). The absolute abundance of numerous C, N, P, S and methane cycling related genes increased significantly (p < 0.05) under eCO(2). Furthermore, the microbial community structure and function were correlated with certain measured plant characteristics. Hence, the microbial ecosystem of the tomato greenhouse soil system was stimulated under eCO(2). These results contribute to a greater understanding of how eCO(2) in the atmosphere affects terrestrial ecosystem stability.