부산대학교 도서관

Plant immune responses are associated with the production of an extensive amount of reactive oxygen and nitrogen species (ROS/RNS), which dramatically alter cellular redox homeostasis. Nucleoredoxin 1 (NRX1) belongs to Thioredoxin (TRX) superfamily, found in most eukaryotic organisms, responsible for redox regulations, protects antioxidant enzymes such as catalase from ROS-induced oxidation, and protects the plant from oxidative stress. In the nucleus, NRX1 interacts with transcription factor TCPs, which are essential components of cellular machinery that sustain homeostasis with adverse and diverse environmental conditions, and are involved in plant development and immunity. In this study, I found that in Yeast 2-hybrid assay, NRX1 interacted with TCP19 and TCP20, and negatively contributed to plant immunity. In plants, autoimmunity regulated by two natural defensive responses, PAMP-triggered immunity (PTI), which acts as the foundation of plant immunity, and effector-triggered immunity (ETI), which induces robust resistance. I showed that TCP19 and TCP20 contributed to plant auto-immunity by evaluating the function of TCP19 and TCP20 against infection with Pseudomonas syringae pv. tomato DC3000 and other P.syringae strains to analyse the effectivity of PTI and ETI. PAMP-triggered immunity (PTI) responses like callose deposition, PR1 protein accumulation, and Pst DC3000 hrcC¯ growth, altered in the absence of TCP19 and TCP20 compared to wild type. Moreover, RPM1 and RPS2 mediated HR and ion leakage are enhanced. Mutant analyses revealed that loss of NRX1 and TCP19 function also increased resistance against virulent and avirulent Pst strains, which signifies that NRX1 and TCP19 suppress plant defense against pathogen infection, and their interaction negatively regulates plant immunity.