title: Regulation of wheat seed dormancy by after-ripening is mediated by specific transcriptional switches that induce changes in seed hormone metabolism and signaling.
abstract: Treatments that promote dormancy release are often correlated with changes in seed hormone content and/or sensitivity. To understand the molecular mechanisms underlying the role of after-ripening (seed dry storage) in triggering hormone related changes and dormancy decay in wheat (Triticum aestivum), temporal expression patterns of genes related to abscisic acid (ABA), gibberellin (GA), jasmonate and indole acetic acid (IAA) metabolism and signaling, and levels of the respective hormones were examined in dormant and after-ripened seeds in both dry and imbibed states. After-ripening mediated developmental switch from dormancy to germination appears to be associated with declines in seed sensitivity to ABA and IAA, which are mediated by transcriptional repressions of PROTEIN PHOSPHATASE 2C, SNF1-RELATED PROTEIN KINASE2, ABA INSENSITIVE5 and LIPID PHOSPHATE PHOSPHTASE2, and AUXIN RESPONSE FACTOR and RELATED TO UBIQUITIN1 genes. Transcriptomic analysis of wheat seed responsiveness to ABA suggests that ABA inhibits the germination of wheat seeds partly by repressing the transcription of genes related to chromatin assembly and cell wall modification, and activating that of GA catabolic genes. After-ripening induced seed dormancy decay in wheat is also associated with the modulation of seed IAA and jasmonate contents. Transcriptional control of members of the ALLENE OXIDE SYNTHASE, 3-KETOACYL COENZYME A THIOLASE, LIPOXYGENASE and 12-OXOPHYTODIENOATE REDUCTASE gene families appears to regulate seed jasmonate levels. Changes in the expression of GA biosynthesis genes, GA 20-OXIDASE and GA 3-OXIDASE, in response to after-ripening implicate this hormone in enhancing dormancy release and germination. These findings have important implications in the dissection of molecular mechanisms underlying regulation of seed dormancy in cereals.
authors: Department of Plant Science, University of Manitoba, Winnipeg, Manitoba, Canada.
authors: Aihua
authors: A
authors: Liu
authors: Feng
authors: F
authors: Gao
authors: Yuri
authors: Y
authors: Kanno
authors: Mark C
authors: MC
authors: Jordan
authors: Yuji
authors: Y
authors: Kamiya
authors: Mitsunori
authors: M
authors: Seo
authors: Belay T
authors: BT
authors: Ayele
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism / Q000494:pharmacology; D029681:Arabidopsis Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D042002:Chromatin Assembly and Disassembly / Q000187:drug effects; D003517:Cyclopentanes / Q000378:metabolism / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D005875:Gibberellins / Q000378:metabolism / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000378:metabolism / Q000494:pharmacology; D054883:Oxylipins / Q000378:metabolism / Q000494:pharmacology; D010711:Phosphatidate Phosphatase / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D057445:Plant Dormancy / Q000187:drug effects; D010937:Plant Growth Regulators / Q000378:metabolism / Q000494:pharmacology; D000071636:Protein Phosphatase 2C; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D012639:Seeds / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D015398:Signal Transduction; D014158:Transcription, Genetic / Q000187:drug effects*; D014908:Triticum / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D014452:Ubiquitins / Q000378:metabolism
chemical_list: C409743:ABI5 protein, Arabidopsis; D029681:Arabidopsis Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D003517:Cyclopentanes; D005875:Gibberellins; D007210:Indoleacetic Acids; D054883:Oxylipins; D010937:Plant Growth Regulators; D014452:Ubiquitins; C011006:jasmonic acid; C030737:indoleacetic acid; D000040:Abscisic Acid; C071570:SNF1-related protein kinases; D017346:Protein Serine-Threonine Kinases; C112948:lipid phosphate phosphatase; D010749:Phosphoprotein Phosphatases; D000071636:Protein Phosphatase 2C; D010711:Phosphatidate Phosphatase