Gen

e ex

pres

sion

(si

gnal

inte

nsit

y)

Control

OsmoticSalt

Drought

Root

0

200

400

600

800

Control 0.5 1 3 6 12 24

Gen

e ex

pres

sion

(si

gnal

inte

nsit

y)

ControlOsmotic

SaltDrought

Shoot

Treatment time (h)

200

400

600

800

Control 0.5 1 3 6 12 24

Treatment time (h)

Fig. S1. Analysis of bHLH122 responses to various abiotic stresses using the publically available Arabidopsis eFP Browser microarray database (http://www.bar.utoronto.ca/efp/cgi-bin/efpWeb.cgi). Error bars represent means ± SE ( n=3).

0

3

6

9

12Col

35::bHLH122-13

35S::bHLH122-1

160 180

NaCl (mM)Control

Bio

mas

s (m

g p

lan

t-1)

Col35S::bHLH122#13 #1

Col35S::bHLH122#13 #1

Control NaCl (160 mM)

(a) (b)

Fig. S2. Effect of NaCl on the growth of Col-0 and 35S::bHLH122 seedlings. (a) After 96 h of stratification, seeds of different genotypes were grown in a vertical position for 4 days on MS medium and then transferred to medium containing various concentrations of NaCl for an additional 10 days in a vertical position. The photographs show representative seedlings. (b) Biomass of Col-0 and 35S::bHLH122 plants in response to NaCl. Error bars represent means ± SE of approximately 60 plants from three independent experiments

Col 35S::bHLH122-13

35S::bHLH122-135S::bHLH122-15

Control

Col 35S::bHLH122-13

35S::bHLH122-135S::bHLH122-15

Mannitol (200 mM)

Ger

min

atio

n (%

)

0

20

40

60

80

100

120

100 200 300

Col 35S::bHLH-1335S::bHLH-1 35S::bHLH-15

ControlMannitol (mM)

A B

Fig. S3. Effects of mannitol on the germination and growth of Col-0 and 35S::bHLH122 plants. (a) Effects of mannitol on the seedling growth of Col-0 and 35S::bHLH122 plants on MS medium containing 200 mM mannitol. Seeds were germinated and grown for 10 days. The photographs show representative seedlings. (b) Germination was assessed 96 h after the end of stratification. Error bars represent means ± SE of approximately 150 seeds from three independent experiments.

0

5

10

15

20At4g09760

0

2

4

6

Col#13 #1

35S::bHLH122

#15

Rel

ativ

e ex

pre

ssio

n

At5g15450

0

0.3

0.6

0.9

1.2At5g57560

Col #13 #1

35S::bHLH122

#15 0

1

2

3

4

5At3g14205

Col #13 #1

35S::bHLH122

#15

0

1

2

3

Rel

ativ

e ex

pre

ssio

n

Col #13 #1

35S::bHLH122

#15

At5g64940

0

0.3

0.6

0.9

1.2At4g17490

Col #13 #1

35S::bHLH122

#15 Col #13 #1

35S::bHLH122

#15

Fig. S4. Analysis of transcript levels in the Col-0 and 35S::bHLH122 transgenic plants. Real-time RT-PCR was used to analyze the expression levels of indicated loci. Real-time RT-PCR quantifications were normalized to the expression of Tub4. Error bars represent means ± SE (n=3).

At3g14205

At4g17490

At5g64940

Fig. S5. Schematic diagrams of G-box/E-box motifs in promoter fragments evaluated in ChIP assays. The region between two arrows denoted the amplified fragments in ChIP