Newswise — South Dakota State University faculty members from four departments will work on improving the ability of nitrogen-fixing bacteria to colonize soybean roots through the South Dakota Biofilm Science and Engineering Center. This research seeks to leverage these bacteria to reduce the need for chemical fertilizer and, thereby, increase the sustainability of agriculture.

The new collaborative research center is part of a five-year, $20 million National Science Foundation Research Infrastructure Improvement Track-1 grant awarded to the South Dakota Established Program to Stimulate Competitive Research and the South Dakota Board of Regents. Faculty from 11 South Dakota universities and colleges will be involved in the biofilms research center.

Of the $10 million in funding designated for the research center, SDSU will receive $3.4 million. From SDSU, eight faculty members, two postdoctoral researchers and approximately 10 graduate students will be involved in the project. In addition, Shana Harming, SDSU’s Wokini Initiative program director, will lead tribal outreach efforts with professor Ben Sayler, director of the Center for the Advancement of Math and Science Education at Black Hills State University.

“In a natural environment, nitrogen-fixing bacteria must compete with thousands of other bacteria to colonize the soybean roots,” explained associate professor Sen Subramanian, whose research spans the departments of biology and microbiology and agronomy, horticulture and plant science. He will lead the SDSU team along with associate professor Zhengrong (Jimmy) Gu of the Department of Agricultural and Biosystems Engineering.

When soybean seeds are inoculated with nitrogen-fixing bacteria, only 50 percent of the soybean plant nodules are occupied by the inoculant strains, Subramanian pointed out. “Our major focus is to make these inoculant strains more competitive in colonizing plants.”

Professor Volker Brozel and assistant professor Nicholas Butzin of the Department of Biology and Microbiology will provide expertise in bacteriology to examine the interface between the plants and the microbial communities. 

Understanding biofilm formation

“The overarching theme of the research is to understand the fundamental interaction between the microbes, which form communities known as biofilms, and the surfaces to which they adhere,” said South Dakota School of Mines and Technology professor of chemical and biological engineering Robb Winter, who will lead the new biofilms research center. The S.D. Mines team will play a primary role in investigating sulfate-reducing bacteria that corrode metals.

“We want to inhibit the harmful microbes and promote the beneficial ones using thin, single-layered 2D materials. These are crystalline materials that are 1 atom in thickness,” Winter explained.

“The crux of both projects is how surface properties affect bacteria attachment and biofilm formation,” said Subramanian, who will use the 2D material as a substrate to which the nitrogen-fixing bacteria can attach.

Gu, whose expertise is in graphene—one of the most well-known 2D materials, will formulate the substrates using new fabrication equipment. A new submicron 3D printer will allow the SDSU researchers to build specialized microfluidic chambers to observe the nitrogen-fixing bacteria colonizing the soybean roots. The Department of Agricultural and Biosystems Engineering will also be hiring a new faculty member with expertise in microfluidics to work on the project.

Analyzing genetics of attachment

Another key aspect focuses on understanding the genetics associated with microbe attachment. “We want to understand the genetic responses of these microbes as they attach to the surface and form biofilms,” Winter said.

This part will generate a vast amount of information on the genetics side utilizing and supporting SDSU’s Genomics Sequencing Center. Analysis of this data to identify meaningful relationships requires the use of machine learning. The University of South Dakota team, led by assistant professor Carol Lushbough, a computer scientist, will spearhead this portion of the research.

“We need to work across disciplines and, in this case, across institutions to solve the complicated problems that we face today and into the future,” said Winter.

“We are working at the interface between engineering and biology to understand the rules of life,” Subramanian concluded.