title: Irrepressible MONOPTEROS/ARF5 promotes de novo shoot formation.
abstract: In vitro regeneration of complete organisms from diverse cell types is a spectacular property of plant cells. Despite the great importance of plant regeneration for plant breeding and biotechnology, its molecular basis is still largely unclear and many important crop plants have remained recalcitrant to regeneration. Hormone-exposure protocols to trigger the de novo formation of either roots or shoots from callus tissue demonstrate the importance of auxin and cytokinin signaling pathways, and genetic differences in these pathways may contribute to the highly divergent responsiveness of plant species to regeneration protocols. In this study, we show that signaling through MONOPTEROS (MP)/AUXIN RESPONSE FACTOR 5 is necessary for the formation of shoots from Arabidopsis calli. Most strikingly, an irrepressible variant of MP, MPΔ, is sufficient for promoting de novo shoot formation through pathways involving the genetically downstream functions of SHOOT MERISTEMLESS (STM) and CYTOKININ RESPONSE FACTOR2 (CRF2). We conclude that the MPΔ genotype can promote de novo shoot formation and can be used to probe corresponding signaling pathways.
authors.affiliation: Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada.
authors.forename: Wenzislava
authors.initials: W
authors.lastname: Ckurshumova
authors.affiliation: Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Smirnova
authors.affiliation: Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada.
authors.forename: Danielle
authors.initials: D
authors.lastname: Marcos
authors.affiliation: Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada.
authors.forename: Yara
authors.initials: Y
authors.lastname: Zayed
authors.affiliation: Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, ON, M5S 3B2, Canada.
authors.forename: Thomas
authors.initials: T
authors.lastname: Berleth
mesh_terms: D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D009154:Mutation; D018520:Plant Shoots / Q000254:growth & development*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013234:Stem Cells; D046509:Tissue Culture Techniques; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C111371:MONOPTEROS protein, Arabidopsis; D014157:Transcription Factors
keywords: Arabidopsis; Auxin Response Factors; CYTOKININ RESPONSE FACTOR2 (CRF2); in vitro shoot formation; monopteros (MP); plant regeneration