Project Details
Projekt
Carotology: Are apocarotenoids conserved modulators of streptophyte physiology?
Applicant
Professor Dr. Jan de Vries
Subject Area
Evolution and Systematics of Plants and Fungi
Plant Physiology
Plant Physiology
Term
since 2020
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 440231723
One major challenge for the earliest land plants was overcoming environmental stressors. The plastid of land plants is recognized as a hub for sensing environmental cues by emanating signals, linking plastid and cell physiology. A major class of these signals are the apocarotenoids that emerge from cleavage of carotenoids. In the first funding period of MAdLand, my team and I have garnered data that land plants and streptophyte algae share the production of a range of stress-relevant apocarotenoids known as signals in embryophytes. Now, we want to understand which physiological and molecular responses these molecules elicit. We will test the hypothesis that the apocarotenoids β-cyclocitral, β-ionone, and dihydroactinidiolide induce conserved response patterns tied with stress signaling; for all work, we will use the MAdLand systems Mesotaenium endlicherianum, Zygnema circumcarinatum, and Physcomitrium patens as a land plant reference. To dissect responses to apocarotenoids, we will pursue three synergistic objectives: (1) Measure the impact of apocarotenoids on zygnematophyte and land plant growth, photophysiology, and feedbacks on upstream isoprenoid metabolism; we will illuminate the physiological impact of apocarotenoids shared by land plants and algae. (2) Infer apocarotenoid-triggered global response patterns shared across 600 million years of streptophyte evolution; integrating RNAseq and phosphoproteomic data will pinpoint comprehensive response patterns—candidates for signal transduction to downstream responses—that we can compare to infer a shared homologous signaling network. (3) Probe the conservation of the signaling pathway; while a range of effects of apocarotenoids will be assessed in 1 and 2 in a top-down approach, we also have clear candidates: the phytohormone salicylic acid and (co-)orthologs of ELONGATED HYPOCOTYL 5 (HY5) and PHYTOCHROME INTERACTING FACTOR 3 (PIF3) in Mesotaenium, Zygnema, and Physcomitrium. We will test for the conservation of these routes via (i) inter-species complementation experiments with the algal genes in Physcomitrium patens hy5 and pif knock-out mutants that were already generated and (ii) salicylic acid quantification. In sum, we will obtain comprehensive data on the physiological impact of apocarotenoids; concomitantly, we will delve into signaling using a top-down and a targeted candidate-based approach. Our data will be projected onto the phylogeny of Phragmoplastophyta and compared to published data on land plants and co-expression data on streptophyte algae. Combined, we will address four defined core topics of MAdLand (i-iv): (i) testing that a molecular chassis for modulation of stress physiology through apocarotenoids evolved in streptophyte algae; (ii) inferring that these regulatory patterns occurred in the last common ancestor of land plants and Zygnematophyceae; (iii) probing their role as molecular adaptations in the response to (iv) abiotic terrestrial challenges.
DFG Programme
Priority Programmes
