S3.1: Functional characterization of known and candidate regulatory proteins that are (potentially) required for N-hydroxpipecolic acid (NHP)-induced gene expression

Christiane Gatz & Xin Li & Yuelin Zhang

Pathogen attack does not only elicit local defense responses at the site of infection, but it also activates immune responses in uninfected parts of the plant (systemic acquired resistance, SAR). According to the current model, a mobile signal is generated in the locally infected leaf that primes systemic leaves to respond in a more efficient way to further pathogen attack. SAR requires two regulatory metabolites: salicylic acid (SA) and N-hydroxy-pipecolic acid (NHP), which are both found in increased amounts in SAR leaves.



In the last funding periods, we have found that NHP treatment alone is sufficient to induce a subset of SAR genes (Nair, Goyal et al., 2021). At least in the model plant Arabidopsis thaliana, this response requires basal levels of the plant defence hormone salicylic acid and the salicylic acid receptor NPR1. Based on unpublished genetic and transcriptomic analyses we have identified known and novel candidate regulatory proteins that are required for NHP-induced gene expression at basal SA levels. The project is designed to address the function and mechanism of action of these proteins in the NHP-specific signalling pathway using genetic, molecular and biochemical methods. The project is closely connected to the project entitled “Priming of a the salicylic acid receptor NPR1 in the course of systemic acquired resistance (SAR)”.
The project is done in collaboration with Profs. Yuelin Zhang and Xin Li at UBC Vancouver who address the research question of NHP perception and signalling by taking alternative approaches (Liu et al., 2020).

References:
Nair, A., Goyal, I. Voß, E., Mrozek, P. , Prajapati, S., Thurow C., Tietze, L., Tittmann, K., and Gatz, C.: N-hydroxypipecolic acid-induced transcription requires the salicylic acid signaling pathway at basal SA levels. Plant Phys. 187, 2803–2819 10.1093/plphys/kiab433 (2021)
Liu, Y., Sun, T., Sun, Y., Zhang, Y., Radojicic, A., Ding, Y., Tian, H., Huang, X., Lan, J., Chen, S., Orduna, A.R., Zhang, K., Jetter, R., Li, X., and Zhang, Y. Diverse Roles of the Salicylic Acid Receptors NPR1 and NPR3/NPR4 in Plant Immunity. Plant Cell 32, 4002-4016. 10.1105/tpc.20.00499 (2020)