Investigating the Role of Tomato Plasma Membrane Protein RLK15 in Tomato Defense Responses to Bacterial Infection

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Abstract/Contents

Abstract
Economically important crop plants such as tomato are under constant threat of attack from bacterial pathogens which colonize leaf interior spaces and replicate. Lacking specialized immune cells, plants rely on the innate immunity of their cells to defend against pathogens. In leaves, both stomatal and apoplastic immune responses play key roles in preventing bacterial entry and replication within the tissue. The plasma membrane (PM) is the interface across which these interactions occur. Plant PM proteins termed Pattern Recognition Receptors (PRRs) interact with other PM proteins to activate early intracellular plant defenses following recognition of conserved microbial molecules termed Microbe-Associated Molecular Patterns (MAMPs). Recently, our lab has shown that one PM protein in tomato, Tomato Atypical Receptor-Like Kinase 1 (TARK1), plays a role in positively regulating apoplastic immunity and negatively regulating stomatal immunity. A proteomics screen was performed to identify TARK1 interacting partners and elucidate TARK1’s functions. This led to the identification of a Receptor Like Kinase, designated RLK15, whose function was unknown. To determine if RLK15 played a role in immunity against bacteria, I conducted pre- and post-invasion infection assays with tomato lines with altered RLK15 expression. In pre-invasion assays, I obtained data suggesting that RLK15 may positively regulate stomatal immunity. In post-invasion assays, I found that RLK15 protein accumulates in response to pathogen infection but is not necessary for TARK1 accumulation. I also found that RLK15 nonfunctional mutants demonstrated increased resistance to Xanthomonas strain Xe ∆xopN (deficient in the XopN effector) while RLK15 overexpression lines displayed greater susceptibility to Pseudomonas strain Pst COR- (deficient in production of the virulence factor coronatine). Quantification of reactive oxygen species (ROS) production and salicylic acid (SA) production in response to bacterial elicitation suggests that RLK15 may play a role in the suppression of ROS and SA production during bacterial infection. Taken together, my findings highlight the importance of RLK15 in pre- and post-invasion immune responses to bacteria in tomato.

Description

Type of resource text
Date created June 2020

Creators/Contributors

Author Robinson, Spencer
Primary advisor Mudgett, Mary Beth
Advisor Dinneny, José
Advisor Guzman, Andrew
Advisor Kim, Jung-Gun
Degree granting institution Stanford University, Department of Biology, 2020

Subjects

Subject Biology
Subject Pattern-triggered immunity
Subject tomato immunity
Subject pre-invasion defense
Subject post- invasion defense
Subject pattern recognition receptors
Subject reactive oxygen species
Subject salicylic acid
Subject Xanthomonas euvesicatoria
Subject Pseudomonas syringae pathovar tomato
Genre Thesis

Bibliographic information

Location https://purl.stanford.edu/yp935qn0358

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This work is licensed under a Creative Commons Attribution Share Alike 3.0 Unported license (CC BY-SA).

Preferred citation

Robinson, Spencer, Guzman, Andrew, Kim, Jung-Gun, Dinneny, José and Mudgett, Mary Beth. (2020). Investigating the Role of Tomato Plasma Membrane Protein RLK15 in Tomato Defense Responses to Bacterial Infection. Stanford Digital Repository. Available at: https://purl.stanford.edu/yp935qn0358

Collection

Undergraduate Theses, Department of Biology, 2019-2020

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Contact information

spence98@stanford.edu

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