title: FIERY1 regulates light-mediated repression of cell elongation and flowering time via its 3'(2'),5'-bisphosphate nucleotidase activity.
abstract: Light is one of the most important environmental factors that regulate plant development. Here we report that a mutation in the Arabidopsis FIERY1 gene (FRY1) caused a shortened hypocotyl and shorter petioles, most dramatically under low-intensity red light and less pronounced under far-red and blue-light conditions. Furthermore, the fry1 mutant flowered late, probably due to a reduced level of FLOWERING LOCUS T (FT) transcript. However, although the transcript level of FRY1 was light-regulated, the chlorophyll level and the expression of typical light-regulated genes were not affected in the fry1 mutant. FRY1 is known as a regulator of abiotic stress responses, and its protein product has dual enzymatic activity comprising inositol polyphosphate-1-phosphatase and 3'(2'),5'-bisphosphate nucleotidase activity. Genetic complementation data obtained using cDNA of the FRY1 paralog AHL (Arabidopsis HAL2-like) and the similar phenotype of an xrn2/xrn3 double mutant suggest that FRY1 attenuates light responses via its 3'(2'),5'-bisphosphate nucleotidase activity rather than its inositol polyphosphate-1-phosphatase activity. We discuss the relationship between the FRY1-associated nucleotidase activity, a step in the pathway for sulfur metabolism and utilization, and the Arabidopsis light response.
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN 37996-0840, USA.
authors.forename: Byung-Hoon
authors.initials: BH
authors.lastname: Kim
authors.forename: Albrecht G
authors.initials: AG
authors.lastname: von Arnim
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D049108:Cell Enlargement; D002734:Chlorophyll / Q000378:metabolism; D035264:Flowers / Q000235:genetics / Q000254:growth & development*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005816:Genetic Complementation Test; D008027:Light; D016254:Mutagenesis, Insertional; D009708:Nucleotidases / Q000235:genetics / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases; D051939:Phytochrome B / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D018749:RNA, Plant / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; C418905:FT protein, Arabidopsis; C497952:PHYB protein, Arabidopsis; D018749:RNA, Plant; D051939:Phytochrome B; D002734:Chlorophyll; D009708:Nucleotidases; D010744:Phosphoric Monoester Hydrolases; C053087:inositol-1,4-bisphosphate 1-phosphatase; C053354:bisphosphoadenylate 3'-nucleotidase