Abscisic Acid, High-Light, and Oxidative Stress Down-Regulate a Photosynthetic Gene via a Promoter Motif Not Involved in Phytochrome-Mediated Transcriptional Regulation  Staneloni Roberto J. , Rodriguez-Batiller María José , Casal Jorge J.   Molecular Plant  Volume 1, Issue 1, Pages 75-83 (January 2008) DOI: 10.1093/mp/ssm007 Copyright © 2008 The Authors. All rights reserved. Terms and Conditions

Figure 1 ABA down-regulates Lhcb12 activity in seedlings grown under continuous FR but not in seedlings grown in darkness. Two-day-old seedlings bearing the –453 bp Lhcb1*2 promoter fused to the GUS reporter were exposed to FR or left in darkness in factorial combination with or without the application of ABA 60 min prior to the beginning of the light treatment. Seedlings were harvested 24 h after the beginning of FR. Data are means and SE of three replicate samples from a representative experiment. Molecular Plant 2008 1, 75-83DOI: (10.1093/mp/ssm007) Copyright © 2008 The Authors. All rights reserved. Terms and Conditions

Figure 2 The abi1-1 mutation increases Lhcb1*2 activity and reduces the response to ABA. Two-day-old seedlings bearing the –176 bp Lhcb1*2 promoter fused to the GUS reporter were exposed to FR with or without the application of ABA 60 min prior to the beginning of the FR treatment and harvested 24 h after the beginning of FR. Data are means and SE of three replicate samples from a representative experiment. Molecular Plant 2008 1, 75-83DOI: (10.1093/mp/ssm007) Copyright © 2008 The Authors. All rights reserved. Terms and Conditions

Figure 3 Definition of a cis-acting region of the Lhcb1*2 promoter required for repression by ABA. (A) Deletion analysis of the promoter. The GATA1-m and AAAATCT-m promoter mutations are included as controls. Data are means and SE of three replicate samples from a representative experiment. (B) Mutation analysis of promoter activity in seedlings grown in darkness. Data are means and SE of three replicate samples from a representative experiment. (C) Mutation analysis of promoter activity in seedlings grown under continuous FR. Data are means and SE of six (–171, –153, –147, –143, –139), nine (–159, –165) or 12 (control) replicate samples from two, three or four independent transgenic lines (three replicates per line), respectively. Two-day-old seedlings were exposed to FR (A, C) with or without the application of ABA 60 min prior to the beginning of the FR treatment and harvested 24 h after the beginning of FR. Molecular Plant 2008 1, 75-83DOI: (10.1093/mp/ssm007) Copyright © 2008 The Authors. All rights reserved. Terms and Conditions

Figure 4 A cis-acting region of the Lhcb1*2 promoter required for repression by ABA is also necessary for repression by glucose, NaCl, and PEG. (A) Response of the wild-type (–453 bp) and –165 mutated promoter to different concentrations of glucose. (B) Response of the wild-type (–453 bp) and –165 mutated promoter to different concentrations of NaCl. (C) Response of the wild-type (–453 bp) and –165 mutated promoter to different concentrations of PEG. Two-day-old etiolated seedlings were transferred to a growth medium containing the indicated concentrations of NaCl, glucose, or PEG, transferred to FR 60 min later and harvested after 24 h under FR. Data are means and SE of three replicate samples from a representative experiment. Molecular Plant 2008 1, 75-83DOI: (10.1093/mp/ssm007) Copyright © 2008 The Authors. All rights reserved. Terms and Conditions

Figure 5 The –165 promoter, which fails to respond to ABA, shows normal repression by low temperature. Two-day-old seedlings were transferred to 24 h continuous FR at 22°C while 3-d-old seedlings were transferred to 24 h continuous FR at 4°C. All the seedlings were harvested at the end of FR. The extra day given to plants transferred to 4°C was given to equilibrate the size of the seedlings at harvest. Seedlings grown for an extra day do not show reduced Lhcb activity if subsequently transferred to FR at 22°C (data not shown). Data are means and SE of five replicate samples from a representative experiment. Molecular Plant 2008 1, 75-83DOI: (10.1093/mp/ssm007) Copyright © 2008 The Authors. All rights reserved. Terms and Conditions

Figure 6 A cis-acting region of the Lhcb1*2 promoter required for repression by ABA is also involved in repression by high light. Two-day-old etiolated seedlings were transferred to a white-light photoperiod (16 h light, 8 h darkness) of the indicated fluence rate before harvest. Data are means and SE of three replicate samples from a representative experiment. Molecular Plant 2008 1, 75-83DOI: (10.1093/mp/ssm007) Copyright © 2008 The Authors. All rights reserved. Terms and Conditions

Figure 7 A cis-acting region of the Lhcb1*2 promoter required for repression by ABA is also necessary for full repression by hydrogen peroxide. Two-day-old etiolated seedlings were transferred to agar containing the indicated concentrations of MV, incubated further 60 min in darkness, transferred to a white-light photoperiod (16 h light at 55 μmol m−2 s−18 h darkness) and harvested 24 h later. Data are means and SE of six replicate samples. Molecular Plant 2008 1, 75-83DOI: (10.1093/mp/ssm007) Copyright © 2008 The Authors. All rights reserved. Terms and Conditions

Figure 8 The –165 promoter, which fails to respond to ABA, shows normal repression by Norflurazon. After chilling, Norflurazon was added to the water solution, wetting the filter paper support to obtain the indicated final concentrations. Two-day-old etiolated seedlings were transferred to a white-light photoperiod (16 h light at 55 μmol m−2 s−18 h darkness) and harvested 24 h later. Data are means and SE of three replicate samples from a representative experiment. Molecular Plant 2008 1, 75-83DOI: (10.1093/mp/ssm007) Copyright © 2008 The Authors. All rights reserved. Terms and Conditions