title: Light influences cytokinin biosynthesis and sensing in Nostoc (cyanobacteria).
abstract: Cytokinins are an important group of plant hormones that are also found in other organisms, including cyanobacteria. While various aspects of cytokinin function and metabolism are well understood in plants, the information is limited for cyanobacteria. In this study, we first experimentally confirmed a prenylation of tRNA by recombinant isopentenyl transferase NoIPT2 from Nostoc sp. PCC 7120, whose encoding gene we previously identified in Nostoc genome along with the gene for adenylate isopentenyl transferase NoIPT1. In contrast to NoIPT2, the transcription of NoIPT1 was strongly activated during the dark period and was followed by an increase in the cytokinin content several hours later in the light period. Dominant cytokinin metabolites detected at all time points were free bases and monophosphates of isopentenyladenine and cis-zeatin, while N-glucosides were not detected at all. Whole transcriptome differential expression analysis of cultures of the above Nostoc strain treated by cytokinin compared to untreated controls indicated that cytokinin together with light trigger expression of several genes related to signal transduction, including two-component sensor histidine kinases and two-component hybrid sensors and regulators. One of the affected histidine kinases with a cyclase/histidine kinase-associated sensory extracellular domain similar to the cytokinin-binding domain in plant cytokinin receptors was able to modestly bind isopentenyladenine. The data show that the genetic disposition allows Nostoc not only to produce free cytokinins and prenylate tRNA but also modulate the cytokinin biosynthesis in response to light, triggering complex changes in sensing and regulation.
authors.affiliation: Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic.
authors.forename: Jitka
authors.initials: J
authors.lastname: Frébortová
authors.affiliation: Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic.
authors.forename: Ondřej
authors.initials: O
authors.lastname: Plíhal
authors.affiliation: Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic.
authors.forename: Vendula
authors.initials: V
authors.lastname: Florová
authors.affiliation: Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic.
authors.forename: Filip
authors.initials: F
authors.lastname: Kokáš
authors.affiliation: Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic.
authors.forename: Karolina
authors.initials: K
authors.lastname: Kubiasová
authors.affiliation: Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic.
authors.forename: Marta
authors.initials: M
authors.lastname: Greplová
authors.affiliation: Department of Chemical Biology and Genetics, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Šimura
authors.affiliation: Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University and Institute of Experimental Botany, The Czech Academy of Sciences, Šlechtitelů 27, 783 71, Olomouc, Czech Republic.
authors.forename: Ondřej
authors.initials: O
authors.lastname: Novák
authors.affiliation: Department of Molecular Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71, Olomouc, Czech Republic.
authors.forename: Ivo
authors.initials: I
authors.lastname: Frébort
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D003583:Cytokinins / Q000096:biosynthesis*; D008027:Light; D046937:Nostoc / Q000378:metabolism*; D054876:Prenylation; D012329:RNA, Bacterial / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D003583:Cytokinins; D012329:RNA, Bacterial; D012343:RNA, Transfer; D019883:Alkyl and Aryl Transferases; C024274:adenylate isopentenyltransferase
keywords: 
  Nostoc
  ; RNA-seq; cytokinin; expression profiling; miaA; sensor kinase; tRNA IPT