CSB Departmental Seminar: Dr. Jeff Dangl, UNC Chapel Hill

                           Departmental Seminar
    
Dr. Jeffery Dangl
HHMI and Dept of Biology, Carolina Center for Genome Sciences
University of North Carolina at Chapel Hill
     
“The Plant Immune System and its Interactions with the Root Microbiome”

Host:  Prof. Darrell Desveaux
  
Video Conferencing at UTM (DV 4001) & UTSc (MW 229)

Abstract:

The plant immune system is a sophisticated two-tiered receptor-based system that utilizes transmembrane pattern recognition receptors to survey microbe associated molecular patterns (MAMPs). Recognition mediated by this ‘first tier’ of the plant immune system generates a set of downstream responses that are sufficient to stop the growth of most microbes, termed MTI (MAMP-triggered immunity). Pathogens, by definition, can surpass or evade MTI and they do so by deploying into the host cell suites of virulence effectors. Plants have therefore evolved a second, intracellular receptor system, consisting of NLR proteins, which monitor effectors directly as ligands, or via their alteration of NLR-associated host targets. Activation of an NLR essentially ‘re-boots’ suppressed MTI, but does so in a very rapid and high amplitude manner termed ETI (Effector-triggered immunity).

Our first set of goals are to understand how particular pathogen effector proteins have evolved to manipulate host signaling machinery to function as virulence factors; how these molecular manipulations are recognized by the intracellular NLR receptors; and how NLR activation initiates a successful immune response. Our rationale is that by understanding how a broad collection of virulence factors from evolutionarily diverse pathogens act inside the host cell, we will better understand the normal defense relevant function of their targets.

Our second set of goals is to understand how the microbiome colonizing the root rhizosphere and the root-intercellular endophytic compartment is organized. The root microbiome contributes to plant growth and development, crop productivity, carbon sequestration and phytoremediation. Colonization of the rhizosphere and endophyte compartment occurs in the presence of a sophisticated plant immune system, suggesting finely-tuned discrimination of pathogens from mutualists and commensals. The principles that govern the winnowing of the complex soil microbial community into host-specific rhizosphere and endophyte compartments are largely unknown. We are defining these principles via characterization of the Arabidopsis rhizosphere microbiome using synthetic microbial communities.