Genomic Science Program
U.S. Department of Energy | Office of Science | Biological and Environmental Research Program

Modulating Bioenergy Traits in Field-Grown Sorghum Affects the Rhizosphere Bacterial Communities

Authors:

Yen Ning Chai1* (ynchai@lbl.gov), Jutta Dalton1, Yang Tian1, Christopher De Ben2, Daniel H. Putnam2, Aymerick Eudes1, Henrik V. Scheller1, Jay Keasling1

Institutions:

1Joint BioEnergy Institute; 2University of California–Davis

Goals

Determine how bioenergy crop engineering affects interactions with soil microbes.

Abstract

Engineering bioenergy crops for reduced cell wall recalcitrance and increased production of high-value chemicals represents a promising approach to sustainably produce biofuels from both economic and environmental standpoints. Yet, the impact of modifying bioenergy traits in feedstocks on the indigenous soil microbiome of agricultural lands remains largely uncharacterized. The project profiled the rhizosphere bacterial communities associated with transgenic sorghum lines engineered for reduced cell wall recalcitrance (AT10) and increased protocatechuate production (Qsub) via 16s amplicon sequencing. The team found that the rhizosphere bacterial community composition was different between the transgenic sorghum lines and wildtype. In the rhizosphere of transgenic lines, researchers detected an enrichment of the phyla (Actinobacteriota, Bacteroidota, and Proteobacteria) that are generally considered as copiotrophs, which thrive on labile carbons and grow rapidly under nutrient-rich conditions. Conversely, the team observed a depletion in the abundance of oligotrophic phyla (Planctomycetota, Acidobacteriota) known for adapting to nutrient-poor conditions and having a slower growth rate. These findings suggest that reducing cell wall integrity and increasing secretion of bioproducts may favor and induce the proliferation of copiotrophic bacteria in soil. Such alterations in soil microbial communities could impact soil health and various soil processes, including nutrient turnover and greenhouse gas emissions, highlighting the importance for further investigation.

Funding Information

This work conducted by the Joint BioEnergy Institute was supported by the Office of Science, BER program, of the U.S. DOE under Contract No. DE-AC02-05CH11231.