Supporting Information Legends
Figure S1. Relative transcript levels of genes encoding first-wave transcription factors in Arabidopsis
plants exposed to low temperature.
WT plants (Col-0) were grown at 22oC under a 16-h photoperiod for 2 weeks, transferred to a
chamber at 4oC and rosettes were harvested at the indicated time points starting at 3 h after dawn.
Transcript levels were determined using qRT-PCR with IPP2 as the reference gene. The 0 h time
point was set to 1. Error bars show SE from 3 biological replicates.
Figure S2. Amino acid sequence of CBF2Δc.
The glutamine136 that is converted to a stop codon in CBF2Δc is shown in red. The AP2/ERF DNA
binding domain is indicated by a single underline. The activation domain defined by Wang et al.
(2005) for CBF1 is indicated by the double underline.
Figure S3. CBF2 transcript levels (endogenous and transgenic) in WT and CBF2overexpressing plants.
WT (Ws-2) and CBF-overexpressing line E2 seedlings were grown on nutrient agar
plates under constant light for 11 days prior to cold treatment for 2 h. Relative
transcript levels were determined by qRT-PCR with actin3 as the reference gene.
The value for the E2 sample was set at 1.
Figure S4. Cold induction of GOLS3 is dependent on the CBF-CRT/DRE regulatory
module.
WT plants (Ws2) and transgenic lines overexpressing CBF2Δc (DN89 and DN96)
were grown at 22°C, transferred to 4°C for the indicated times, and relative transcript
levels for GOLS3 were determined by qRT-PCR using ubq10 as the reference gene.
The experiment was repeated 3 times; the graph is from a representative
experiment. Error bars are SD for three technical replicates. WT (Ws2) 24 h cold
was set to 1.
Figure S5. Overexpression of first-wave transcription factors does not affect
expression of GA-associated genes. WT (Col-0) and two independent transgenic
lines (OX1, OX2) overexpressing the indicated transcription factors were grown at
22oC under a 16-h photoperiod for 2 weeks. Relative transcript levels of GA2ox3,
GA2ox6, and RGL3 were measured by qRT-PCR. IPP2 was used as the reference
gene. The average value for the WT samples was set to 1. Error bars indicate the
SE of three biological replicates.
Table S1. Genes differentially expressed in WT Arabidopsis (Ws-2) plants exposed
to low temperature (24 h at 4°C).
Table S2. Genes differentially expressed at warm temperature (22°C) in transgenic
Arabidopsis (Ws-2) plants overexpressing CBF1, CBF2 or CBF2 and
correspondingly induced or repressed in WT Arabidopsis (Ws-2) plants exposed to
low temperature (24 h at 4°C).
Table S3. Cold-regulated genes in WT Arabidopsis (Col-0) plants.
Table S4. Robust COR genes.
Table S5. COR genes regulated by first-wave transcription factors.
Table S6. HSCF1 regulon genes up-regulated by first-wave transcription factors.
Table S7. Differential expression of CBF2 regulon genes in response to low
temperature (24 h at 4°C) in WT Arabidopsis (Ws-2) plants and transgenic
Arabidopsis (Ws-2) plants overexpressing CBF2∆c.
Table S8. Primers used in cloning genes encoding first-wave transcription factors.
Table S9. Primers used for qRT-PCR.
Methods S1. Constructs and plant transformation.
Methods S2. R-script used for CBF expression microarray analysis.