Summer Research Fellowship Programme of India's Science Academies

Optimization of gene expression condition of Pseudomonas syringae Type III effector, AvrRps4  

Mrudul Lal M P

PSG College of Arts and Science, Coimbatore

Dr. Saikat Bhattacharjee

Assistant professor, Laboratory of Signal Transduction & Plant Resistance, Regional Centre for Biotechnology, Faridabad


Plants are a rich source of nutrients for many organisms. Even though lacking a circulating immune system comparable to animals, plants have developed a set of structural, chemical, and protein-based defenses designed to detect entering organisms and stop them before they are able to cause considerable damage. Plant immunity is the built-in or developed capacity of plants to withstand biological attack by pathogens. The plant immune system has two layers - the first layer is pathogen-associated molecular patterns- (PAMPs) triggered immunity (PTI) and the second layer is effector-triggered immunity (ETI), which is initiated by specific recognition of pathogen type III secreted effectors (T3SEs) with plant intracellular resistance (R) proteins. Pathogens secrete effector proteins into the host cells to handle those cells to their benefit, but effector – triggered immunity (ETI) occurs when the host resistance proteins recognize the effector. Pseudomonas syringae, a Gram-negative phytopathogenic bacteria, translocates effector proteins into plant cells to disrupt host defences. These effectors can be recognized by plant immune receptors, activate defense responses that restrict pathogen growth. AvrRps4, an effector protein from Pseudomonas syringae pv. pea, triggers RPS4-dependent immunity in resistant accessions of Arabidopsis thaliana. The aim of this study was the optimization of gene expression condition of Pseudomonas syringae Type III effector, AvrRps4. To study the structural and functional involvement of the AvrRps4 effector in activation of plant defense, we tried to optimize the gene expression condition for the purification of AvrRps4 protein.

Keywords: Optimization of gene expression condition, Pseudomonas syringae type III effector AvrRps4, effector triggered immunity, plasmid isolation, competent cell preparation, protein purification by affinity and column chromatography

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