title: The evolution of the plant genome-to-morphology auxin circuit.
abstract: In his Generelle Morphologie der Organismen (1866), 150 years ago, Ernst Haeckel (1834-1919) combined developmental patterns in animals with the concept of organismic evolution, and 50 years ago, a new era of plant research started when focus shifted from crop species (sunflower, maize etc.) to thale cress (Arabidopsis thaliana) as a model organism. In this contribution, we outline the general principles of developmental evolutionary biology sensu Haeckel and describe the evolutionary genome-to-morphology-plant hormone auxin (IAA, indole-3-acetic acid)-circuit with reference to other phytohormones and a focus on land plants (embryophytes) plus associated epiphytic microbes. Our primary conclusion is that a system-wide approach is required to truly understand the ontogeny of any organism, because development proceeds according to signal pathways that integrate and respond to external as well as internal stimuli. We also discuss IAA-regulated embryology in A. thaliana and epigenetic phenomena in the gametophyte development, and outline how these processes are connected to the seminal work of Ernst Haeckel.
authors.affiliation: Institute of Biology, University of Kassel, 34109, Kassel, Germany. kut@uni-kassel.de.
authors.forename: Ulrich
authors.identifier: http://orcid.org/0000-0001-8095-2180
authors.initials: U
authors.lastname: Kutschera
authors.affiliation: Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA.
authors.forename: Karl J
authors.initials: KJ
authors.lastname: Niklas
mesh_terms: D005075:Biological Evolution; D015509:Developmental Biology / Q000266:history*; D044127:Epigenesis, Genetic; D053263:Gene Regulatory Networks; D017343:Genes, Plant; D018745:Genome, Plant; D055993:Germ Cells, Plant; D049672:History, 19th Century; D049673:History, 20th Century; D049674:History, 21st Century; D007210:Indoleacetic Acids; D010944:Plants / Q000235:genetics; D015398:Signal Transduction; D014157:Transcription Factors
chemical_list: D007210:Indoleacetic Acids; D014157:Transcription Factors
keywords: Auxin; Gene networks; IAA; Plant evolution; Transcription factors