Article reSeArcH
WT moca1
0 mM NaCl
60 mM^0620 [NaCl] (mM)^400
WT
moca1
0
10
K content (mg g
–1 DW)
5
0620 40 0
WT
moca1
[NaCl] (mM)
0
2
4
Na content (mg g
–1 DW)
6
WT
moca1
1
2
–NaCl +NaCl
[Ca2+]i (Cameleon)
0.2
[Ca
2+
] (Fi
535
/F
485
)
20 s
WT
moca1
d
080
[NaCl] (mM)
20 6040
WT
moca1
0
We
ight (mg FW
per seedling)
6
4
2
Na
+/H
+ exchange
(^6 %
F min
–1 mg
–1)
[NaCl] (mM)
06080
NS **** WT
***
50
100
Survival rate (%)
0
c
a
g h
b
f
e
NaCl
NS ***
moca1
40
30
20
0
10
WT moca1
–NaCl
+NaCl
***
NS
Fig. 2 | The moca1 mutant is defective in the SOS pathway and
hypersensitive to salt stress. a, b, Increases in [Ca^2 +]i induced by NaCl
in roots. YC3.6 emission images were taken every 3 s, and 200 mM NaCl
was added at the time indicated (a). Emission ratios are shown using a
pseudo-colour scale and quantified from experiments similar to these in
a (b; mean ± s.d.; n = 10 seedlings). Similar results were seen in more
than ten independent experiments. c, Plants were grown on half-strength
Murashige and Skoog (½ MS) medium containing 0.2 mM CaCl 2 with or
without 60 mM NaCl for 12 days. Similar results were seen in more than
ten independent experiments. d, e, Fresh weight (FW; d) and survival
rate (e) from experiments similar to those in c were quantified. Data are
from five independent experiments (mean ± s.d.; n = 12 pools (8–12
seedlings per pool); two-way ANOVA, P < 0.001; NS, not significant;
***P < 0.001). f, Na+/H+ exchange activity from plants treated with
water or 100 mM NaCl for 24 h (mean ± s.d.; n = 3; **P < 0.01).
g, h, The content of Na (g) a nd K (h) of plants from experiments similar to
those in c. Data are presented as mean ± s.e.m. (n = 6; two-way ANOVA,
P < 0.001).
abc
d e f
i
150
300
0
ROI (
μm)
036 72 108
Low High
150
300
0
moca1
01030 60 150
WT
Time after NaCl treatment (s)
Low [Ca2+]i High
NaCl
0 0.2 0.4
6 [Ca2+]i (F 535 /F 485 )
WT
mo
ca1
0.1 0.3
4
1
0
4210 16 2
3
2
WT
Temperature (°C)
moca1
0 200
[LiCl] (mM)
50 100 150
WT
1.2
0.8
0.4
1.6
0
moca1
0
1.2
0.8
0.4
1.6 WT
moca1
[H 2 O 2 ] (mM)
01510 5
2
1
0
0 200 600
WT
400
3
[CaCl 2 ] (mM)
moca1
0 200
[NaNO 3 ] (mM)
50 100 150
WT
1.2
0.8
0.4
1.6
0
moca1
0 200
[KCl] (mM)
50 100 150
WT
0
1.2
0.8
0.4
1.6
moca1
gh
[Ca
2+
] (i
μM)
[Ca
2+
] (i
μM)
[Ca
2+
] (i
μM)
[Ca
2+
] (i
μM)
[Ca
2+
] (i
μM)
[Ca
2+
] (i
μM)
[Ca2+]i
Time after NaCl treatment (s)
ROI (
μm)
Fig. 3 | The moca1 mutant abolishes [Ca^2 +]i spikes and waves induced
by monovalent cations. a−c, Increases in [Ca^2 +]i in seedlings plotted as a
function of applied [H 2 O 2 ] (a), temperature gradient (b), and [CaCl 2 ] (c).
Data are from three independent experiments similar to those in Fig. 1a–c
(mean ± s.d.; n = 32 seedlings; two-way ANOVA; a, P = 0.64; b, P = 0.06;
c, P = 0.11). d−f, Increases in [Ca^2 +]i plotted as a function of applied
[KCl] (d), [LiCl] (e), and [NaNO 3 ] (f). Data are from three independent
experiments (mean ± s.d.; n = 32 seedlings; two-way ANOVA, P < 0.001).
g−i, Wave-like propagation of [Ca^2 +]i through the root 1,000 μm from
the site at which root-tip was treated with 200 mM NaCl was analysed via
YC3.6 imaging. Images in regions of interest (ROIs) at indicated times
are shown (g; scale bar, 200 μm). The wave dynamics of [Ca^2 +]i were
examined shootward from roots similar to the ROIs in g by repeatedly
analysing images taken every 2 s, and data from five roots were averaged
and pseudo-colour coded (h). Similar results were seen in more than 20
independent experiments. Changes in peaks of [Ca^2 +]i waves in ROIs were
quantified from experiments similar to those in g (i; mean ± s.d.; n = 21
roots; Student’s t-test, P < 0.001).
15 AUGUSt 2019 | VOl 572 | NAtUre | 343