A role for brassinosteroid signalling in decision-making processes in the Arabidopsis seedling

• Published in: PLoS genetics Vol. 18; no. 12; p. e1010541
• Main Authors: Kalbfuß, Nils, Strohmayr, Alexander, Kegel, Marcel, Le, Lien, Grosse-Holz, Friederike, Brunschweiger, Barbara, Stöckl, Katharina, Wiese, Christian, Franke, Carina, Schiestl, Caroline, Prem, Sophia, Sha, Shuyao, Franz-Oberdorf, Katrin, Hafermann, Juliane, Thiemé, Marc, Facher, Eva, Palubicki, Wojciech, Bolle, Cordelia, Assaad, Farhah F
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 12-12-2022; Public Library of Science (PLoS)
• Subjects: Abiotic stress; Allelomorphism; Arabidopsis; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Biology and Life Sciences; Brassinosteroids; Cell division; Conflicts of interest; Decision making; Decision theory; Elongation; Ethylenediaminetetraacetic acid; Gene Expression Regulation, Plant; Genetic aspects; Genetic screening; Germination; Growth; Hypocotyl; Identification and classification; Influence; Light; Meristems; Methods; Mutants; Nutrients; Phenotypes; Potassium; Protein Kinases - metabolism; Resource allocation; Scanning electron microscopy; Seedlings; Seeds; Social Sciences; Germany
• ISSN: 1553-7404; 1553-7390; 1553-7404
• DOI: 10.1371/journal.pgen.1010541

Plants often adapt to adverse conditions via differential growth, whereby limited resources are discriminately allocated to optimize the growth of one organ at the expense of another. Little is known about the decision-making processes that underly differential growth. In this study, we developed a screen to identify decision making mutants by deploying two tools that have been used in decision theory: a well-defined yet limited budget, as well as conflict-of-interest scenarios. A forward genetic screen that combined light and water withdrawal was carried out. This identified BRASSINOSTEROID INSENSITIVE 2 (BIN2) alleles as decision mutants with "confused" phenotypes. An assessment of organ and cell length suggested that hypocotyl elongation occurred predominantly via cellular elongation. In contrast, root growth appeared to be regulated by a combination of cell division and cell elongation or exit from the meristem. Gain- or loss- of function bin2 mutants were most severely impaired in their ability to adjust cell geometry in the hypocotyl or cell elongation as a function of distance from the quiescent centre in the root tips. This study describes a novel paradigm for root growth under limiting conditions, which depends not only on hypocotyl-versus-root trade-offs in the allocation of limited resources, but also on an ability to deploy different strategies for root growth in response to multiple stress conditions.