Simm, S., Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany, Cluster of Excellence Macromolecular Complexes, Institute for Molecular Cell Biology of Plants, Frankfurt am Main, Germany
Scharf, K.-D., Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany, Cluster of Excellence Macromolecular Complexes, Institute for Molecular Cell Biology of Plants, Frankfurt am Main, Germany
Jegadeesan, S., Department of Vegetable Research, Institute for Plant Sciences, Agricultural Research Organization, Volcani Centre, Bet Dagan, Israel, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
Chiusano, M.L., Department of Soil, Plants Environmental and Animal Production Sciences, Laboratory of Computer Aided Biosciences, University of Studies of Naples Federico II, Portici, Naples, Italy
Firon, N., Department of Vegetable Research, Institute for Plant Sciences, Agricultural Research Organization, Volcani Centre, Bet Dagan, Israel
Schleiff, E., Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany, Cluster of Excellence Macromolecular Complexes, Institute for Molecular Cell Biology of Plants, Frankfurt am Main, Germany

Phytohormones control the development and growth of plants, as well as their response to biotic and abiotic stress. The seven most well-studied phytohormone classes defined today are as follows: auxins, ethylene, cytokinin, abscisic acid, jasmonic acid, gibberellins, and brassinosteroids. The basic principle of hormone regulation is conserved in all plants, but recent results suggest adaptations of synthesis, transport, or signaling pathways to the architecture and growth environment of different plant species. Thus, we aimed to define the extent to which information from the model plant Arabi-dopsis thaliana is transferable to other plants such as Solanum lycopersicum. We extracted the co-orthologues of genes coding for major pathway enzymes in A. thaliana from the translated genomes of 12 species from the clade Viridiplantae. Based on predicted domain architecture and localization of the identified proteins from all 13 species, we inspected the conservation of phytohormone pathways. The comparison was complemented by expression analysis of (co-)orthologous genes in S. lycopersicum. Altogether, this information allowed the assignment of putative functional equivalents between A. thaliana and S. lyco-persicum but also pointed to some variations between the pathways in eudicots, monocots, mosses, and green algae. These results provide first insights into the conservation of the various phytohormone pathways between the model system A. thaliana and crop plants such as tomato. We conclude that orthologue prediction in combination with analysis of functional domain architecture and intracellular localization and expression studies are sufficient tools to transfer information from model plants to other plant species. Our results support the notion that hormone synthesis, transport, and response for most part of the pathways are conserved, and species-specific variations can be found. © the authors, publisher and licensee Libertas Academica Limited.