title: Iron is involved in the maintenance of circadian period length in Arabidopsis.
abstract: The homeostasis of iron (Fe) in plants is strictly regulated to maintain an optimal level for plant growth and development but not cause oxidative stress. About 30% of arable land is considered Fe deficient because of calcareous soil that renders Fe unavailable to plants. Under Fe-deficient conditions, Arabidopsis (Arabidopsis thaliana) shows retarded growth, disordered chloroplast development, and delayed flowering time. In this study, we explored the possible connection between Fe availability and the circadian clock in growth and development. Circadian period length in Arabidopsis was longer under Fe-deficient conditions, but the lengthened period was not regulated by the canonical Fe-deficiency signaling pathway involving nitric oxide. However, plants with impaired chloroplast function showed long circadian periods. Fe deficiency and impaired chloroplast function combined did not show additive effects on the circadian period, which suggests that plastid-to-nucleus retrograde signaling is involved in the lengthening of circadian period under Fe deficiency. Expression pattern analyses of the central oscillator genes in mutants defective in CIRCADIAN CLOCK ASSOCIATED1/LATE ELONGATED HYPOCOTYL or GIGANTEA demonstrated their requirement for Fe deficiency-induced long circadian period. In conclusion, Fe is involved in maintaining the period length of circadian rhythm, possibly by acting on specific central oscillators through a retrograde signaling pathway.
authors: Agricultural Biotechnology Research Center , Academia Sinica, Taipei 11529, Taiwan.
authors: Yong-Yi
authors: YY
authors: Chen
authors: Ying
authors: Y
authors: Wang
authors: Lung-Jiun
authors: LJ
authors: Shin
authors: Jing-Fen
authors: JF
authors: Wu
authors: Varanavasiappan
authors: V
authors: Shanmugam
authors: Munkhtsetseg
authors: M
authors: Tsednee
authors: Jing-Chi
authors: JC
authors: Lo
authors: Chyi-Chuann
authors: CC
authors: Chen
authors: Shu-Hsing
authors: SH
authors: Wu
authors: Kuo-Chen
authors: KC
authors: Yeh
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D002736:Chloroplasts / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D057906:Circadian Clocks / Q000187:drug effects / Q000235:genetics; D002940:Circadian Rhythm / Q000187:drug effects* / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D007501:Iron / Q000494:pharmacology*; D000090463:Iron Deficiencies; D008034:Lincomycin / Q000494:pharmacology; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D009569:Nitric Oxide / Q000494:pharmacology; D011724:Pyridazines / Q000494:pharmacology; D026422:S-Nitrosoglutathione / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013997:Time Factors
chemical_list: D011724:Pyridazines; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione; D008034:Lincomycin; D007501:Iron; C008677:norflurazone