Collaborative Research: Plant Mechanisms Controlling Rhizobial Invasion During Symbiotic Nitrogen-fixing Nodule Development

University Of Delaware, Newark DE

Investigators

Abstract

Almost 90% of legume plants are able to form nitrogen-fixing root nodules in symbiosis with the soil bacteria rhizobia. Nodulated, nitrogen-fixing legumes produce bioavailable nitrogen, one characteristic that makes legumes second only to the cereals in their importance to human nutrition. Development of Symbiotic nitrogen fixing root nodule is a complex process requiring coordination of both the plant host and rhizobial symbionts' differentiation pathways. In previous collaborative work between the Dickstein and Sherrier laboratories, two Medicago truncatula plant mutants, nip (numerous infections with polyphenolics) and sli (sluggish infections) that are defective in the rhizobial infection/invasion process were identified and partially characterized. The current work seeks to define the molecular and cellular defect underpinning these observed nodule mutations. The intellectual merits of tbe project include (1) cell biological analyses of mutants to facilitate the map-based cloning of the nip gene, and (2) characterization of sli with cell biological approaches. The broader impacts of the project include examination of important aspects of the basic biology of nodule development, infection thread growth and symbiosome formation, which have previously been difficult to study. The results of this research might lead to new strategies to improve the efficiency of nodulation and nitrogen fixation. Other broader impacts include the training of a postdoctoral fellow, graduate students, and undergraduate students. Additionally, both Drs. Dickstein and Sherrier's groups are involved in several outreach programs at their respective universities that recruit non-mainstream undergraduate students, underrepresented minority undergraduate students, high school teachers in the summer, and high school students to work in their respective laboratories.