title: Gene Regulation by the AGL15 Transcription Factor Reveals Hormone Interactions in Somatic Embryogenesis.
abstract: The MADS box transcription factor Arabidopsis (Arabidopsis thaliana) AGAMOUS-LIKE15 (AGL15) and a putative ortholog from soybean (Glycine max), GmAGL15, are able to promote somatic embryogenesis (SE) in these plants when ectopically expressed. SE is an important means of plant regeneration, but many plants, or even particular cultivars, are recalcitrant for this process. Understanding how (Gm)AGL15 promotes SE by identifying and characterizing direct and indirect downstream regulated genes can provide means to improve regeneration by SE for crop improvement and to perform molecular tests of genes. Conserved transcription factors and the genes they regulate in common between species may provide the most promising avenue to identify targets for SE improvement. We show that (Gm)AGL15 negatively regulates auxin signaling in both Arabidopsis and soybean at many levels of the pathway, including the repression of AUXIN RESPONSE FACTOR6 (ARF6) and ARF8 and TRANSPORT INHIBITOR RESPONSE1 as well as the indirect control of components via direct expression of a microRNA-encoding gene. We demonstrate interaction between auxin and gibberellic acid in the promotion of SE and document an inverse correlation between bioactive gibberellic acid and SE in soybean, a difficult crop to transform. Finally, we relate hormone accumulation to transcript accumulation of important soybean embryo regulatory factors such as ABSCISIC ACID INSENSITIVE3 and FUSCA3 and provide a working model of hormone and transcription factor interaction in the control of SE.
authors: Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546-0312.
authors: Qiaolin
authors: Q
authors: Zheng
authors: Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546-0312.
authors: Yumei
authors: Y
authors: Zheng
authors: Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546-0312.
authors: Huihua
authors: H
authors: Ji
authors: Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546-0312.
authors: Whitney
authors: W
authors: Burnie
authors: Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546-0312 sperr2@uky.edu.
authors: Sharyn E
authors: 0000-0002-3011-8240
authors: SE
authors: Perry
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000196:embryology* / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D044783:F-Box Proteins / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D017343:Genes, Plant; D005875:Gibberellins / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism*; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010940:Plant Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism; D013025:Glycine max / Q000187:drug effects / Q000196:embryology* / Q000235:genetics
chemical_list: C522473:AGL15 protein, Arabidopsis; D029681:Arabidopsis Proteins; D044783:F-Box Proteins; D005875:Gibberellins; D007210:Indoleacetic Acids; D026161:MADS Domain Proteins; D035683:MicroRNAs; D010937:Plant Growth Regulators; D010940:Plant Proteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D012097:Repressor Proteins; C501405:TIR1 protein, Arabidopsis; C007842:gibberellic acid