Recombinant Pseudomonas syringae pv. tomato 30S ribosomal protein S3 (rpsC)

Introduction

Pseudomonas syringae pv. tomato is a bacterial pathogen known for causing bacterial speck disease in tomatoes and Arabidopsis thaliana . The ability of P. syringae pv. tomato DC3000 to induce disease relies on the type III secretion system (T3SS), which injects effector proteins into plant cells . One of the critical components in bacterial cells, including P. syringae pv. tomato, is the ribosome, essential for protein synthesis. Among the ribosomal proteins, S3 is a key constituent of the 30S ribosomal subunit. The recombinant form of this protein, expressed through genetic engineering, is of interest in studying its function and role within the bacterium.

Ribosomal Protein S3 (RpsC)

RpsC is a component of the 30S ribosomal subunit, which is responsible for binding mRNA and initiating protein synthesis. As a ribosomal protein, S3 is crucial for the assembly and stability of the 30S subunit. Modified or recombinant versions of RpsC can be used to study ribosome function, protein synthesis regulation, and the impact of mutations on bacterial physiology.

Pseudomonas syringae and the Type III Secretion System

P. syringae employs the T3SS to introduce effector proteins into plant cells, which suppresses the plant's immune responses and facilitates infection . The T3SS is encoded by hypersensitive response and pathogenicity genes (hrp), and its functionality is essential for pathogenicity .

Recombinant RpsC in Functional Studies

Producing recombinant RpsC allows for detailed investigations into its functions, interactions, and roles within P. syringae. By manipulating the rpsC gene and expressing it in a controlled manner, researchers can assess the impact of RpsC on various bacterial processes, including virulence and stress responses.

Role of RsmA Proteins in P. syringae

P. syringae pv. tomato DC3000 contains five RsmA protein homologues, with RsmA2 and RsmA3 playing a vital role in the bacterium's interaction with tomato plants . These proteins affect virulence gene expression, γ-amino butyric acid utilization, pyoverdine production, and protease activities . Specifically, RsmA2 and RsmA3 influence bacterial growth and disease symptom development in planta .

GrlP and its Impact on Bacterial Behavior

GrlP, a glycine-rich lipoprotein located in the outer membrane of P. syringae pv. tomato DC3000, is involved in the negative regulation of T3SS gene expression and affects bacterial pathogenicity, swimming motility, biofilm formation, and tolerance to stress conditions . Overexpression of grlp increases the size of the periplasm, influencing the bacterium's interaction with its environment .

Perception of GABA and l-Pro through the PsPto-PscC chemoreceptor

P. syringae uses chemoreceptors like PsPto-PscC to detect compounds released by plants, such as GABA and l-Proline . The recognition of these compounds drives the entry of P. syringae pv. tomato into the tomato apoplast and regulates the plant defense response .

HrpP and Plant Immunity

The T3SS protein HrpP induces host cell death and suppresses pattern-triggered immunity (PTI) in plants . HrpP contributes to the effector translocation ability of the hrpP mutant, further facilitating infection .

Effector Proteins and Plant Defense Suppression

P. syringae pv. tomato DC3000 employs a complex repertoire of type III secretion effector (T3E) proteins to suppress the plant innate immune system . These effectors interact with multiple immunity-associated proteins, complicating their analysis .