Extensive signal integration by the phytohormone protein network.

Nature (2020-07-03)
Melina Altmann, Stefan Altmann, Patricia A Rodriguez, Benjamin Weller, Lena Elorduy Vergara, Julius Palme, Nora Marín-de la Rosa, Mayra Sauer, Marion Wenig, José Antonio Villaécija-Aguilar, Jennifer Sales, Chung-Wen Lin, Ramakrishnan Pandiarajan, Veronika Young, Alexandra Strobel, Lisa Gross, Samy Carbonnel, Karl G Kugler, Antoni Garcia-Molina, George W Bassel, Claudia Falter, Klaus F X Mayer, Caroline Gutjahr, A Corina Vlot, Erwin Grill, Pascal Falter-Braun
ABSTRACT

Plant hormones coordinate responses to environmental cues with developmental programs1, and are fundamental for stress resilience and agronomic yield2. The core signalling pathways underlying the effects of phytohormones have been elucidated by genetic screens and hypothesis-driven approaches, and extended by interactome studies of select pathways3. However, fundamental questions remain about how information from different pathways is integrated. Genetically, most phenotypes seem to be regulated by several hormones, but transcriptional profiling suggests that hormones trigger largely exclusive transcriptional programs4. We hypothesized that protein-protein interactions have an important role in phytohormone signal integration. Here, we experimentally generated a systems-level map of the Arabidopsis phytohormone signalling network, consisting of more than 2,000 binary protein-protein interactions. In the highly interconnected network, we identify pathway communities and hundreds of previously unknown pathway contacts that represent potential points of crosstalk. Functional validation of candidates in seven hormone pathways reveals new functions for 74% of tested proteins in 84% of candidate interactions, and indicates that a large majority of signalling proteins function pleiotropically in several pathways. Moreover, we identify several hundred largely small-molecule-dependent interactions of hormone receptors. Comparison with previous reports suggests that noncanonical and nontranscription-mediated receptor signalling is more common than hitherto appreciated.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
6-Benzylaminopurine, suitable for plant cell culture
Sigma-Aldrich
Methyl jasmonate, 95%
Sigma-Aldrich
3-Indoleacetic acid, suitable for plant cell culture, crystalline