To understand the underlying molecular differences in the gene regulatory network, we characterized the drought-induced Gene Regulatory Network (DGRN) that underlie differential drought response in the three species using a yeast-1-hybrid (Y1H) approach. We identified orthologs that showed divergent expression pattern under drought conditions using the transcriptome of the previous study. Ultimately, we cloned 141 promoters that include a set of 30 complete sets of orthologues, which we screened against a complete Ath transcription factor collection, yielding a regulatory network map consisting of 997 total and 543 distinct interactions that include 135 fully conserved interactions among the species. At the same time, 405 distinct interactions were only identified in a single or two of the three species indicating that these were modulated by the underlying evolutionary processes and are promising candidates for novel drought tolerance genes.
A further major achievement was the generation of a high-quality experimental map of the phytohormone signaling interactome network, in which the phytohormone abscisic acid plays a central role. Using our high-quality interactome mapping pipeline, we generated experimentally a systems-level map of the Arabidopsis phytohormone signaling-network consisting of more than 2,000 binary protein-protein interactions. In the highly interconnected network, pathway communities and hundreds of novel pathway contact points can be identified that represent potential points of crosstalk. Functional validation of candidates in seven hormone pathways demonstrate novel functions for 74% of tested proteins in 84% of candidate interactions, and indicate that a large majority of signaling proteins function pleiotropically in multiple pathways. Moreover, we identify several hundred largely small-molecule-dependent interactions of hormone receptors, especially for ABA receptors and their PP2C co-receptor. Comparison with previous reports suggests that non-canonical and non-transcription mediated receptor signaling is more common than currently appreciated. (Altmann et al., Extensive signal integration by the phytohormone protein network, Nature, 2020.)
Exploitation and dissemination of the results
Major publications:
Altmann M et al, Nature. 2020
Garcia VJ et al, Plant Cell 2020
Wierbowski SD et al, PNAS 2020
Marin-De La Rosa NA et al, New Phytol 2019
Garcia-Molina A,J Exp Bot. 2017
conferences and seminar series, e.g.:
Cold Spring Harbor Laboratory Meeting (CSHL): Network Biology, March 2019 & 2020
EMBO Workshop: International plant systems biology, April 2021
Conference in Roscoff/France: Systems Biology of Plants, August 2018
Forschungszentrum Jülich: HPPS Seminar, May 2018
Helmholtz Munich: Town Hall meeting, Institutes Seminars etc.
television report and interview
