M3.3: Metabolic signals in biotic and abiotic plant
stress biology

Gerhard Braus & James Kronstad

Phytohormones are evolutionarily conserved signal molecules that regulate biotic and abiotic stress responses in vascular plants (Pieterse et al., 2009) and most of them have been described to occur in bryophytes as well (Guillory and Bonhomme, 2021). Starting point of the proposed research project was the working hypothesis that the function of genes of unknown function can be identified by metabolomic approaches that will lead to the annotation of enzyme activities that are involved in regulating plant immunity in Arabidopsis thaliana (Ding et al., 2016; Feussner and Feussner, 2020; Mohnike et al., 2021; Rekhter et al., 2019).

Even though most of the steps involved in the formation and perception of phytohormones are known and the corresponding genes encoding the proteins have been cloned from vascular plants, it is not clear when these signals evolved during phytoterrestrialization. In particular, knowledge on their specific roles and the relative importance of individual molecules in biotic and abiotic plant stress biology is scarce. Therefore, we will examine the biosynthesis and role of phytohormones in plant defense and upon drought stress in the bryophytes Marchantia polymorpha and Physcomitrium patens and compare their function with the situation in the vascular plant Arabidopsis thaliana.


Ding, P., D. Rekhter, Y. Ding, K. Feussner, L. Busta, S. Haroth, S. Xu, X. Li, R. Jetter, I. Feussner, and Y. Zhang: Characterization of a pipecolic acid biosynthesis pathway required for systemic acquired resistance. Plant Cell 28, 2603-2615 (2016).

Feussner, K., and I. Feussner: Ex vivo metabolomics: A powerful approach for functional gene annotation. Trends Plant Sci. 25, 829-830 (2020).


Guillory, A., and S. Bonhomme: Phytohormone biosynthesis and signaling pathways of mosses. Plant Mol. Biol. 107, 245-277 (2021).

Mohnike, L., D. Rekhter, W. Huang, K. Feussner, H. Tian, C. Herrfurth, Y. Zhang, and I. Feussner: The glycosyltransferase UGT76B1 modulates N-hydroxy-pipecolic acid homeostasis and plant immunity. Plant Cell 33, 735–749 (2021).

Pieterse, C.M.J., A. Leon-Reyes, S. Van der Ent, and S.C.M. Van Wees: Networking by small-molecule hormones in plant immunity. Nat. Chem. Biol. 5, 308-316 (2009).


Rekhter, D., D. Lüdke, Y. Ding, K. Feussner, K. Zienkiewicz, V. Lipka, M. Wiermer, Y. Zhang, and I. Feussner: Isochorismate-derived biosynthesis of the plant stress hormone salicylic acid. Science 365, 498-502 (2019).