title: Endogenous abscisic acid promotes hypocotyl growth and affects endoreduplication during dark-induced growth in tomato (Solanum lycopersicum L.).
abstract: Dark-induced growth (skotomorphogenesis) is primarily characterized by rapid elongation of the hypocotyl. We have studied the role of abscisic acid (ABA) during the development of young tomato (Solanum lycopersicum L.) seedlings. We observed that ABA deficiency caused a reduction in hypocotyl growth at the level of cell elongation and that the growth in ABA-deficient plants could be improved by treatment with exogenous ABA, through which the plants show a concentration dependent response. In addition, ABA accumulated in dark-grown tomato seedlings that grew rapidly, whereas seedlings grown under blue light exhibited low growth rates and accumulated less ABA. We demonstrated that ABA promotes DNA endoreduplication by enhancing the expression of the genes encoding inhibitors of cyclin-dependent kinases SlKRP1 and SlKRP3 and by reducing cytokinin levels. These data were supported by the expression analysis of the genes which encode enzymes involved in ABA and CK metabolism. Our results show that ABA is essential for the process of hypocotyl elongation and that appropriate control of the endogenous level of ABA is required in order to drive the growth of etiolated seedlings.
authors.affiliation: Laboratory of Growth Regulators & Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University & Institute of Experimental Botany ASCR, Olomouc, Czech Republic.
authors.forename: Jan F
authors.initials: JF
authors.lastname: Humplík
authors.affiliation: Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Olomouc, Czech Republic.
authors.forename: Véronique
authors.initials: V
authors.lastname: Bergougnoux
authors.affiliation: Department of Botany, Faculty of Science, Palacký University, Olomouc, Czech Republic.
authors.forename: Michaela
authors.initials: M
authors.lastname: Jandová
authors.affiliation: Laboratory of Growth Regulators & Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University & Institute of Experimental Botany ASCR, Olomouc, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Šimura
authors.affiliation: Laboratory of Growth Regulators & Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University & Institute of Experimental Botany ASCR, Olomouc, Czech Republic.
authors.forename: Aleš
authors.initials: A
authors.lastname: Pěnčík
authors.affiliation: Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Palacký University, Olomouc, Czech Republic.
authors.forename: Ondřej
authors.initials: O
authors.lastname: Tomanec
authors.affiliation: Laboratory of Growth Regulators & Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University & Institute of Experimental Botany ASCR, Olomouc, Czech Republic.
authors.forename: Jakub
authors.initials: J
authors.lastname: Rolčík
authors.affiliation: Laboratory of Growth Regulators & Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University & Institute of Experimental Botany ASCR, Olomouc, Czech Republic.
authors.forename: Ondřej
authors.initials: O
authors.lastname: Novák
authors.affiliation: Laboratory of Growth Regulators & Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University & Institute of Experimental Botany ASCR, Olomouc, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Fellner
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors; D003583:Cytokinins / Q000096:biosynthesis / Q000378:metabolism; D003624:Darkness; D062951:Endoreduplication / Q000528:radiation effects*; D018525:Germination / Q000187:drug effects / Q000528:radiation effects; D006706:Homeostasis / Q000528:radiation effects; D018546:Hypocotyl / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism / Q000528:radiation effects*; D018551:Solanum lycopersicum / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism / Q000528:radiation effects*; D063245:Plant Development / Q000187:drug effects / Q000528:radiation effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology
chemical_list: D003583:Cytokinins; D047428:Protein Kinase Inhibitors; D000040:Abscisic Acid; D018844:Cyclin-Dependent Kinases