Harsha Somaya
Somaya, Harsha
Year: 2022
School: Colby College
Faculty Advisor: Michael Gore

Project Summary:

N2O, which has a global warming potential 300x higher than CO2, originates 56-70% from natural soils, predominantly when soil microbes undergo denitrification. However, there has been limited investigation into how different maize genotypes affect the abundance of (de)nitrifying soil microbes. Here, we used the PiCRUSt2 pipeline to evaluate the relationship between maize subpopulations and (de)nitrification microbial abundance. This was accomplished by analyzing 16S rRNA reads generated by Walters et al. from 4,866 rhizosphere samples collected at five field locations. The pipeline analyzes the OTUs (i.e., microbial identification ID) with their abundances and sequences specific to each sample. The main output was the abundance of rhizosphere pathways present in the samples; the focus being on five that influence (de)nitrification. Next, the STAMP statistical package was used to test which genetic, plant developmental time points, and environmental factors were significantly affecting the abundance for each of the five pathways. Bulk soil consistently had different pathway abundances compared to rhizosphere samples. Across all field locations and time points, no significant differences were found in microbial abundance between all pairwise comparisons of five maize subpopulations. When filtering by each field location, only Lansing, NY and Columbia, MO had significant pathway abundance differences when comparing between maize subpopulations. The Gore lab is continuing this research to identify specific maize genotypes that promote soil microbes to have lower nitrous oxide emissions.


My Experience:

I learned immense scientific and soft skills during this internship. My mentor became my friend, and I learned to speak for myself in making a case for my ideas to my PI. I increased my computational skills and realized even professionals do not always know the answers, so collaboration is key. Reaching out to experts who were willing to help also gave me a sense of confidence in utilizing my resources. Furthermore, I discovered the unpredictability of research and enjoyed field work like extracting root samples and exudates. The Wednesday seminars were also very informative; for example, it was unbelievable that a single nucleotide change could increase watermelon growth by more than 3x! I am now thinking about changing my major to Computational Biology and going to graduate school to further analyze genetic data for philanthropic discoveries.