EAGER: High-throughput discovery of microbial genes conferring improved root colonization.

North Carolina State University, Raleigh NC

Investigators

Abstract

Plant roots are surrounded by billions of microscopic organisms called bacteria. These bacteria help the plant obtain nutrients and grow. Because of how important bacteria are, many people are interested in developing fertilizers containing bacteria to help plants grow better. However, it has become clear that while some bacteria, when added to a growing plant, can help them grow under artificial laboratory conditions, hardly any bacteria can help a plant grow when applied under realistic conditions. We would like to understand why some bacteria are able to help plants grow, while some bacteria cannot. To do this, we will study the genes that growth-promoting bacteria have, and determine whether these genes can convert a non-growth-promoting bacteria into a growth-promoting one. This work will be performed in corn, and will train one graduate student. Beneficial microorganisms can greatly improve crop plant performance, motivating their use as seed inoculants. However, exogenous microbes are often outcompeted in the field, which limits their utility and reveals fundamental gaps in our understanding of root colonization. The rationale for this proposal is that the genes that are most important for colonizing the root are largely unknown. Recent work using comparative genomics and knockout mutants has provided the first insights into the genes involved in root colonization. However, a complete picture of colonization must include how to enhance it, an understanding that is not currently available. Since root colonization is multifaceted (encompassing interactions with other microbes, the host, and abiotic soil conditions) it is expected that a diversity of microbial and plant genes will impact root colonization. To parse this complexity, we will use a functional metagenomics approach to screen for genes conferring improved colonization maize under three different nutrient conditions. This work will therefore advance our understanding of root colonization and our ability to identify microbes that exert beneficial effects for prolonged periods. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.