Studying Methanotropic Bacterial Diversity in Ohio Soils Using High-Throughput Sequence Analysis

A Graduate Defense Seminar will be presented by Aditi Sengupta, PhD Candidate on Wednesday (6/17) at 9:00 a.m. in 333C Kottman Hall with a link to 117A Williams Hall. Aditi will present Studying Methanotropic Bacterial Diversity in Ohio Soils Using High-Throughput Sequence Analysis.

Aerobic methanotrophic bacteria in soil oxidize methane and use it as their sole source of carbon and energy, thereby allowing soils to serve as the only known biological sink of atmospheric methane. However, a clear understanding of the diversity and community composition of these bacteria, as affected by landuse and land-management practices is lacking. The objective of this study was to characterize the diversity of methanotrophs in two contrasting soils in Ohio using the sequencing-by-synthesis technique. In addition to location, the effect of rotation, tillage, and management of soils on methanotrophic community was also studied.

A molecular-based high-throughput sequencing technique was employed. Following a pilot pyrosequencing study, Illmina’s sequencing-by-synthesis approach was taken to generate millions of sequences targeting methanotrophic bacteria. A combination of four primer sets targeting whole community 16S rRNA, 16S rRNA gene region of Type I and Type II methanotrophs, and functional pmoA were used. Software packages including Mothur, QIIME (Quantitative Insights Into Microbial Ecology), and R were used to study community diversity and abundance in soils under no-till continuous corn, no-till corn-soybean, plow-till continuous-corn, plow-till corn-soybean, grass, and forest.

The results show that a variety of methanotrophic bacterial operational taxonomic units (OTUs) were identified across different land-use and management, representing diverse genera of methanotrophs. Among the variables analyzed, location was dominant, followed by tillage and rotation. This dissertation added to the knowledge of land-use and land-management practices that can be employed on a long-term basis to increase biological fixation of CH₄ gas.