Lena Knorr (Westfälische Wilhelms-Universität Münster)
Lena Knorr's Master thesis was awarded with the Prize for the Best Plant Science Master Thesis, which was carried out at Westfälische Wilhelms-Universität Münster in the year 2022
Title: The importance of intracellular NAD dynamics in the pattern-triggered immune (PTI) response of plants
Knorr provides insights into PTI-mediated physiological dynamics in the cytosol of plants and gives supporting evidence for the importance of NAD metabolism in plant immunity.
At pathogen attack, the plant cell recognizes conserved pathogen-associated molecular patterns (PAMPs) through pattern recognition receptors (PRRs) leading to the activation of pattern-triggered immunity (PTI), the first line of immunity in plants. Several key mechanisms involved, such as calcium channel regulation, phosphorylation of signalling proteins or the generation of the apoplastic ROS burst, have received extensive attention. These events and the downstream defences they initiate are reliant on a profound re-routing of cellular metabolism. While it is evident that metabolic dynamics are at the heart of the network of pathogen response strategies the specific integration of primary metabolism and pathogen defence programs is poorly understood.
Recently, the metabolic cofactor nicotinamide adenine dinucleotide (NAD) has gained attention as part of the effector-triggered immune response (ETI), which includes the degradation by cellular NAD by TIR-associated NADase activity. Independently, defects in pathogen responses have been observed in mutants affected in NAD metabolism.
The study focuses on the serendipitous observation of an early NAD redox signature in Arabidopsis leaves triggered by the bacterial elicitor flg22. Since the transient is rapid, and difficult to resolve through destructive approaches for NADH/NAD+ quantification, I established a monitoring system for NADH/NAD+ in vivo exploiting the genetically-encoded fluorescent biosensor Peredox-mCherry. This approach has been the basis for testing specific hypotheses as to (i) the characteristics of the NAD redox transient, (ii) its origin and (iii) its potential significance in establishing immunity, by using genetic and chemical interference.
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Lena Sophie Knorr conducted this work at at the Institute of Plant Biology and Biotechnology (IBBP,WWU Münster) in the group of Prof. Markus Schwarzländer.