| NSF Org: |
IOS Division Of Integrative Organismal Systems |
| Recipient: |
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| Initial Amendment Date: | March 4, 2011 |
| Latest Amendment Date: | April 14, 2014 |
| Award Number: | 1025642 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
C. Eduardo Vallejos
IOS Division Of Integrative Organismal Systems BIO Directorate for Biological Sciences |
| Start Date: | March 1, 2011 |
| End Date: | February 29, 2016 (Estimated) |
| Total Intended Award Amount: | $3,136,718.00 |
| Total Awarded Amount to Date: | $4,187,897.00 |
| Funds Obligated to Date: |
FY 2013 = $1,011,988.00 FY 2014 = $1,057,102.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
341 PINE TREE RD ITHACA NY US 14850-2820 (607)255-5014 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
341 PINE TREE RD ITHACA NY US 14850-2820 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Plant Genome Research Project |
| Primary Program Source: |
01001314DB NSF RESEARCH & RELATED ACTIVIT 01001415DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.074 |
ABSTRACT
PI: Alan Collmer (Cornell University)
CoPIs: Zhangjun Fei, Gregory Martin, and Sorina Popescu (Boyce Thompson Institute for Plant Research), Bryant Adams (Wells College), Magdalen Lindeberg (Cornell University) and Dilip Panthee (North Carolina State University Mountain Horticultural Research & Extension Center)
This project is aimed at improving disease resistance in tomato by understanding and manipulating the complex network of protein kinases involved in pathogen perception and defense activation. The immunity-associated kinase system will be probed with two classes of molecules from the model bacterial pathogen Pseudomonas syringae pv. tomato DC3000: elicitors of immunity perceived by kinases at the surface of plant cells, and effectors injected by the pathogen into plant cells to disrupt kinase signaling and thereby suppress immunity. The project exploits genomic resources for tomato and the pathogen, as well as natural variation in the immunity of wild tomato species. A variety of approaches will be used to comprehensively identify and biochemically explore immunity-associated kinases. These include RNA sequencing-based transcriptomic analyses (to identify kinase genes upregulated by pathogen elicitors) and functional protein microarrays (to identify kinases that interact with pathogen molecules). The project will reveal whether the kinases that perceive extracellular pathogen signals or those that function internally to activate defenses are more important in naturally occurring superior resistance. This information will guide strategies for improving tomato resistance to bacterial speck and possibly other diseases. Expected outcomes include fundamental insights into the operation of the immunity-associated kinase system in plants, new tomato breeding lines with improved disease resistance, and an outreach activity involving a game based on molecular plant-pathogen interactions.
Crop plants are susceptible to bacteria and many other microbial pathogens, and the resulting diseases are often difficult to control. Broader impacts of this project include new approaches to disease resistance that may be applicable to many crops and pathogen classes. Additional broader impacts include several outreach activities, most notably, development of an educational video game. Growing knowledge of the "game-like" molecular interactions between plants and pathogens will be used to guide development of a game that will engage students and possibly the broader public in lessons addressing evolution, plant biology, pathogenesis, and agriculture. This will be a strategy/resource game incorporating the costs and benefits of deploying attack and defense molecules. The game will be based on the widely available Adobe Flash platform. In addition, the project will continue to refine and support the High School Connect laboratory modules that are distributed through the Cornell Institute for Biology Teachers. The Pseudomonas-Plant Interaction website (http://pseudomonas-syringae.org), which is interlinked with the Sol Genomics Network (http://solgenomics.net) and the Tomato Functional Genomics Database (http://ted.bti.cornell.edu), will provide public access to all project generated data and biological resources, as well as to the game and other outreach resources.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
This project explored molecular genetic interactions between the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000 and its host tomato (Solanum lycopersicum), with an aim of identifying new sources of resistance against bacterial speck disease of tomato. The Pst DC3000-tomato pathosystem is a general model for studying pathogen-plant interactions. A unique project approach was to use accessions of tomato and its wild relatives, along with pathogen-derived probes, to discover natural variations useful for understanding the pathosystem and for breeding tomato cultivars with more durable disease resistance. A special goal was to better understand the complex system of protein kinases that are key to pathogen perception and immunity activation in tomato.
The pathogen perception system was probed with several microbe-associated molecular patterns (MAMPs), which activate immunity, and with effectors that are injected by the pathogen type III secretion system to suppress immunity (most commonly by targeting kinases). MAMPs, such as bacterial flagellin, are common features of microbes and are recognized by kinase-linked receptors on the surface of plant cells in the first level of plant defense known as pattern-triggered immunity (PTI). Pathogen effector proteins can suppress PTI, but internal receptors associated with the resistance (R) gene system in plants can recognize the presence of individual effectors in a second level of defense known as effector-triggered immunity (ETI). There are many pathogen MAMPs and effectors and many plant immune receptors and associated kinases. An additional complexity is that some pathogen effectors can suppress ETI that would be triggered by other effectors in the same repertoire (or even by other domains in the same effector protein).
Two genome-wide studies of tomato kinases identified specific kinases that are important in immunity. First, a tomato kinase library of 300 full-length genes, along with improved protocols for protoplast transformation and protein-protein interaction assays, revealed the tomato SlBSK7 protein as a candidate interactor with at least two Pst DC3000 effectors. Second, RNA sequencing revealed 92 protein kinase-encoding, flagellin-induced, repressed by effectors (FIRE) genes in tomato, and one of these, a cell wall-associated kinase, has a demonstrable role in immunity. This work provided a high-priority set of kinases for further investigation. RNA sequencing also was used to identify kinase-encoding genes differentially expressed in response to PTI versus ETI, which yielded useful reporter genes and EPK1, a novel protein kinase required for ETI elicited by multiple effectors.
The project identified natural variation in the responsiveness of heirloom tomato varieties to three MAMPs (flg22, flgII-28, and csp22) as well as significant variation in field isolates of Pst. As an example of the latter, a highly virulent strain, NYS-T1, was isolated in central New York in 2009. Sequencing of Pst NYS-T1 and comparison of this strain to other Pst isolates enabled the development of a PCR-based subspecific diagnostic assay to alert growers of the presence of this particularly virulent strain in their tomatoes early in the season. Work with NYS-T1 and related strains also led to the discovery of resistance to a race 1 strain of Pst in a wild relative of tomato. No current tomato varieties have resistance to the increasingly common race 1. Solanum habrochaites accessions that are resistant to race 1 strain T1 were identified. Bulk segregant analysis combined with Illumina sequencing led to the identification of a 650-kb segment on chromosome 2 with Rph1 (Resistance to Pst T1 in S. habrochaites 1) activity, with the aim of now using Rph...
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