1. The bHLH transcription factor SPATULA enables cytokinin signaling, and both activate auxin biosynthesis and transport genes at the medial domain of the gynoecium
- Author
-
Nayelli Marsch-Martínez, Cristina Ferrándiz, Ricardo A. Chávez Montes, Juan José Ripoll, Victor M. Zúñiga-Mayo, Martin F. Yanofsky, Dario Paolo, Karla L. Gonzalez-Aguilera, Ignacio Ezquer, Patricia Ballester, Stefan de Folter, Humberto Herrera-Ubaldo, J. Irepan Reyes-Olalde, Joanna Serwatowska, Lucia Colombo, Alexander Heyl, and Paulina Lozano-Sotomayor more...
- Subjects
Shoot-Meristemless ,0106 biological sciences ,0301 basic medicine ,Auxin efflux ,Cancer Research ,Cytokinins ,Arabidopsis ,Gene Expression ,Plant Science ,Growth ,Biochemistry ,01 natural sciences ,chemistry.chemical_compound ,Gene Expression Regulation, Plant ,Tryptophan Transaminase ,Basic Helix-Loop-Helix Transcription Factors ,Medicine and Health Sciences ,Arabidopsis thaliana ,heterocyclic compounds ,Plant Hormones ,Flower Anatomy ,Flowering Plants ,Genetics (clinical) ,chemistry.chemical_classification ,Genetics ,biology ,Plant Biochemistry ,Plant Anatomy ,food and beverages ,Functional genomics ,Plants ,Crabs-Claw ,Cell biology ,Ovaries ,Phenotypes ,Experimental Organism Systems ,Hormonal-Control ,Differentiation ,Seeds ,Cytokinin ,Anatomy ,B response regulators ,Signal Transduction ,Research Article ,Arabidopsis gynoecium ,Gynoecium ,lcsh:QH426-470 ,Arabidopsis Thaliana ,Meristem ,Carpel development ,Flowers ,Brassica ,Research and Analysis Methods ,03 medical and health sciences ,Model Organisms ,Plant and Algal Models ,Auxin ,DNA-binding proteins ,Gene Regulation ,Molecular Biology ,Transcription factor ,Ecology, Evolution, Behavior and Systematics ,Indoleacetic Acids ,Polarity ,Arabidopsis Proteins ,fungi ,Reproductive System ,Organisms ,Biology and Life Sciences ,Proteins ,biology.organism_classification ,Hormones ,Regulatory Proteins ,lcsh:Genetics ,030104 developmental biology ,chemistry ,Fruit ,Auxins ,Transcription Factors ,010606 plant biology & botany - Abstract
[EN] Fruits and seeds are the major food source on earth. Both derive from the gynoecium and, therefore, it is crucial to understand the mechanisms that guide the development of this organ of angiosperm species. In Arabidopsis, the gynoecium is composed of two congenitally fused carpels, where two domains: medial and lateral, can be distinguished. The medial domain includes the carpel margin meristem (CMM) that is key for the production of the internal tissues involved in fertilization, such as septum, ovules, and transmitting tract. Interestingly, the medial domain shows a high cytokinin signaling output, in contrast to the lateral domain, where it is hardly detected. While it is known that cytokinin provides meristematic properties, understanding on the mechanisms that underlie the cytokinin signaling pattern in the young gynoecium is lacking. Moreover, in other tissues, the cytokinin pathway is often connected to the auxin pathway, but we also lack knowledge about these connections in the young gynoecium. Our results reveal that cytokinin signaling, that can provide meristematic properties required for CMM activity and growth, is enabled by the transcription factor SPATULA (SPT) in the medial domain. Meanwhile, cytokinin signaling is confined to the medial domain by the cytokinin response repressor ARABIDOPSIS HISTIDINE PHOSPHOTRANSFERASE 6 (AHP6), and perhaps by ARR16 (a type-A ARR) as well, both present in the lateral domains (presumptive valves) of the developing gynoecia. Moreover, SPT and cytokinin, probably together, promote the expression of the auxin biosynthetic gene TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS 1 (TAA1) and the gene encoding the auxin efflux transporter PIN-FORMED 3 (PIN3), likely creating auxin drainage important for gynoecium growth. This study provides novel insights in the spatiotemporal determination of the cytokinin signaling pattern and its connection to the auxin pathway in the young gynoecium., IRO, VMZM, HHU and PLS were supported by the Mexican National Council of Science and Technology (CONACyT) with a PhD fellowship (210085, 210100, 243380 and 219883, respectively). Work in the SDF laboratory was financed by the CONACyT grants CB-2012-177739, FC-2015-2/1061, and INFR-2015-253504, and NMM by the CONACyT grant CB-2011-165986. SDF, CF and LC acknowledge the support of the European Union FP7-PEOPLE-2009-IRSES project EVOCODE (grant no. 247587) and H2020-MSCARISE-2015 project ExpoSEED (grant no. 691109). SDF also acknowledges the Marine Biological Laboratory (MBL) in Woods Hole for a scholarship for the Gene Regulatory Networks for Development Course 2015 (GERN2015). IE acknowledges the International European Fellowship-METMADS project and the Universita degli Studi di Milano (RTD-A; 2016). Research in the laboratory of MFY was funded by NSF (grant IOS-1121055), NIH (grant 1R01GM112976-01A1) and the Paul D. Saltman Endowed Chair in Science Education (MFY). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. more...
- Published
- 2017
- Full Text
- View/download PDF