How do bacteria infect plants and how do plants defend themselves from such attacks?
The long-term goal of research in the Martin laboratory is to use knowledge gained about the molecular basis of plant-pathogen interactions to develop plants with increased natural resistance to diseases. Such plants would require fewer applications of pesticides producing economic and environmental benefits while providing food for consumers with less pesticide residue.
The Martin laboratory studies the molecular basis of bacterial infection processes and the plant immune system. The research focuses on speck disease which is caused by the infection of tomato leaves with the bacterial pathogen Pseudomonas syringae pv. tomato. This is an economically important disease that can decrease both the yield and quality of tomato fruits. It also serves as an excellent experimental system for studying the molecular mechanisms that underlie plant-pathogen interactions and how they have evolved. Many experimental resources, including an increasing number of genome sequences, are available for both tomato and P. s. pv. tomato. Current work relies on diverse experimental approaches involving methods derived from the fields of biochemistry, bioinformatics, cell biology, forward and reverse genetics, genomics, molecular biology, plant breeding, plant pathology and structural biology.
In the interaction of Pseudomonas with tomato, the plant responds rapidly to a potential infection by detecting certain conserved molecules expressed by the pathogen. At this stage, the pathogen uses a specialized secretion system to deliver virulence proteins, such as AvrPto and AvrPtoB, into the plant cell. These pathogen proteins suppress early host defenses and thereby promote disease susceptibility. Some tomato varieties express a resistance gene, Pto, which encodes a protein that detects the presence of AvrPto or AvrPtoB and activates a second strong immune system that halts the progression of bacterial speck disease.
The Martin lab is currently studying many aspects of the molecular mechanisms that underlie the bacterial infection process and the plant response to infection. One project takes advantage of the genetic natural variation present in wild relatives of tomato to identify new genes that contribute to plant immunity. These genes provide insights into the plant immune system and also can be bred into new tomato varieties to enhance disease resistance. A second project relies on next-generation sequencing methods to identify tomato genes whose expression increases during the interaction with P. s. pv. tomato. The expression of these genes is then reduced by using virus-induced gene silencing or the genes are mutated using CRISPR/Cas9 to test whether they make a demonstrable contribution to immunity.
Martin Lab Pedigree
Evolution of immunity
Evolution of pathogen recognition and defense responses in wild species of tomato and tomato heirloom varieties.
The plant immune system 1: Mechanisms underlying recognition and response to microbe-associated molecular patterns.
The plant immune system II: Mechanisms underlying recognition and response to pathogen effector proteins.
AvrPto virulence mechanisms
Virtulence mechanisms of the AvrPto effector protein from Pseudomonas syringae pv. tomato.
Methods to study plant immunity
Development of methods and resources to study the plant immune system.
Nicotiana benthamiana genome project
Nicotiana benthamiana genome project.
- This month, the cover of Molecular Plant-Microbe Interactions features a publication by Simon Schwizer from the Martin Lab at BTI that furthers our understanding of how tomatoes are able to resist infection by Pseudomonas syringae, the causal agent of bacterial speck, a common disease in upstate NY. Read more »
- Professor Greg Martin and colleagues received an NSF grant to pursue research into resistance against bacterial speck disease in tomatoes. Read more »
More news about the Martin Lab
A New Method for Studying Plant-Germ Warfare, Oct 7, 2016
Collaboration to Identify New Sources of Disease Resistance in Tomato, Sep 12, 2016
New System in Tomato’s Defense against Bacterial Speck Disease, Sep 1, 2016
BTI Faculty Honor Former Advisor, Steve Tanksley, Jun 16, 2016
BTI Intern Picks Up Awards on His Way to Berkeley, May 9, 2016
The “Speck”-ter Haunting New York Tomato Fields, Nov 9, 2015
Scientists Find New Tool for Pathogen to Pillage Plants, Jun 15, 2015
Patrick Boyle Off to Private Sectore, Dec 3, 2014
André Velasquez Receives Prestigious McClintock Award, Mar 14, 2012
At the Frontline of a Plant-Pathogen Molecular Arms Race, Dec 8, 2011
Salmonella and Tomato Infection Interactions to Be Investigated, Jul 28, 2011
Invasion of the Plant Pathogens, Apr 5, 2011
Dr. Gregory Martin to Receive Award for Excellence in Molecular Plant Pathology, Jul 6, 2010
The Martin laboratory studies the molecular basis of plant immunity and bacterial pathogenesis. Our focus is on the infection of tomato by Pseudomonas syringae pv. tomato as this process results in bacterial speck, an economically important disease, and also serves as a powerful model system for understanding fundamental mechanisms involved in plant-pathogen interactions. On the plant side, we identify and characterize genes, proteins and molecular mechanisms that play a role in host immunity and susceptibility. This work relies on natural variation for these traits that is present in cultivated tomato and in the 12 wild relatives of tomato that occur in South America. On the bacterial side, we study the proteins and associated mechanisms that the pathogen uses to interfere with the plant immune response. For the characterization of both plant and bacterial genes and proteins, we use a variety of experimental approaches including biochemistry, bioinformatics, genetics, genomics, molecular biology, and structural biology.
Examples of research projects for undergraduates in my laboratory include: 1) molecular characterization of novel isolates of Pseudomonas syringae pv. tomato collected during a recent outbreak of bacterial speck disease in New York; and 2) Identifying and characterizing immunity-associated genes from wild relatives of tomato. For more information about the Martin lab, please visit the various sections on this page or the Plant Pathology website.
Interns in the Martin Lab are funded by NSF IOS-1451754 and REU-1358843.
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