slgcs 3b meristemoid 3a 2 4 - plant physiology · mmc meristemoid slgc gmc stoma secondary...
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Protoderm
MMC
Meristemoid
SLGC
GMC
Stoma secondarymeristemoid
secondarystoma
1
2
3a3b
4
5
4b
5b
SLGCs
SLGCs
Supplemental Figure 1. Stomatal development in Arabidopsis.
Developmental steps that lead to stomata formation. A protodermal cell acquires MMC fate (orange). The MMC executes the first asymmetric division that generates a meristemoid (yellow) and an SLGC (blue). The meristemoid can undergo additional asymmetric divisions, amplifying the number of SLGCs, and ultimately it differentiates into a GMC (purple), of which the symmetric division produces the guard cell (GC) pair that constitutes the stoma (green). Secondary or satellite stomata can be formed when a SLGC asymmetrically divides away from the primary stoma.
Col-0 ldc
Supplemental Figure 2. Adaxial cotyledon phenotype exhibited by the ldc mutant.
DIC images showing complete 15-day-old adaxial cotyledons of Col-0 and ldc. Bar = 0.5 mm.
Supplemental Figure 3. Genetic mapping of the ldc mutation and SPCH protein sequence indicating known domains and amino acid changes of the point mutants.
(A) Genetic map of Arabidopsis presenting the 32 microsatellite markers (purple lines) used for the genetic mapping of the ldc mutation. Each black rectangle represents a chromosome (I to V). Inset shows the genome region in which the ldc mutation had reduced recombination rates (r) and the physical position of the SPCH locus (blue line). (B) SPCH amino acid sequence with colored domains (blue for bHLH, yellow for MAP KINASE TARGET DOMAIN [MPKTD], and green for the plant specific C-terminal domain (SPCH, MUTE and FAMA) [SMF]) and point amino acid changes for the different mutants (red).
I II III IV V
MNB8
r=0%
MUA2
r=4%
SPCH
SPCH (At5g53210) aminoacid sequence
MQEIIPDFLEECEFVDTSLAGDDLFAILESLEGAGEISPTAAST
PKDGTTSSKELVKDQDYENSSPKRKKQRLETRKEEDEEEED
RàW (spch-5)
GDGEAEEDNKQDGQQKMSHVTVERNRRKQMNEHLTVLRSL
bHLH
MPCFYVKRGDQASIIGGVVEYISELQQVLQSLEAKKQRKTYA
EVLSPRVVPSPRPSPPVLSPRKPPLSPRINHHQIHHHLLLPPIS
MPKTD
PRTPQPTSPYRAIPPQLPLIPQPPLRSYSSLASCSSLGDPPPY
VàM (spch-2)
SPASSSSSPSVSSNHESSVINELVANSKSALADVEVKFSGAN
SMF
VLLKTVSHKIPGQVMKIIAALEDLALEILQVNINTVDETMLNSFT
Qàstop (spch-1)
IKIGIECQLSAEELAQQIQQTFC
A
B
* * *
Supplemental Figure 4. Epidermal DIC images of several mature organs in Col-0 and spch-5.
Stomata are false-colored in purple for better identification. Brackets mark stomatal clusters. Bars = 20 µm.
SE
PAL
PE
DIC
EL
SIL
IQU
ES
TAM
EN
FILA
ME
NT
PE
TAL
STA
ME
N
Col-0
] ]
STE
MH
YP
OC
OTY
L
spch-5
0
10
20
30
40
50
60
70
80
S
D (
sto
ma
ta
/m
m )2
0
5
10
15
20
25
SI
(%)
Col
-0
spch-5
Col
-0
spch-5
*
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6O
A (
cm
)2
Col
-0
spch-5
n.d
0
20
40
60
80
100
Col-0 spch-5
0
50
100
150
200
250
PC
D (
ce
lls/m
m2)
*
<1,000
1,000-2,000
2,000-5,000
5,000-10,000
10,000-15,000
>15,000
Pavement cell size distribution
size(µm2)
%
DC
ADAXIAL
]
]
ABAXIAL
spch-5
Col
-0
Col
-0
spch-5
A
B
Supplemental Figure 5. spch-5 third-leaf epidermal phenotype.
(A) DIC images of the adaxial and abaxial epidermis of Col-0 and spch-5 in third leaves of 28-day-old plants. Stomata are highlighted in purple and clusters marked by brackets. Bars = 50 µm. (B) Graphs representing stomatal index, stomatal density, organ area and pavement cell density in abaxial epidermis of 28-day-old third leaves. Grey and orange denote Col-0 and spch-5, respectively. Asterisks indicate P < 0.05 (Student’s t test; n = 10) and n.d P > 0.05. Error bars represent SE. (C) Representative drawings of Col-0 and spch-5 with color code as in (D). Stomata are indicated in purple. (D) Size distribution of pavement cells in Col-0 and spch-5. Frequency of large pavement cells is much higher in the mutant than in the wild type. Bar = 100 µm.
Supplemental Figure 6. Additional data derived from cell tracking of leaf primordia shown in Figure 2.
Graphs elaborated from leaves (n = 5) per genotype and with 50 cells at initial field (T0). (A) Percentage of entry divisions. (B) Number of SLGCs per lineage. (C) Percentage of primary and secondary lineages. (D) Stomatal differentiation rate. Asterisk in (B) denotes P < 0.05 (Student’s t test). Error bars represent SE.
0
0.5
1
1.5
2
2.5
Col-0 spch-5nu
mbe
r
SLGCs/lineage
*
B
0
0.2
0.4
0.6
0.8
1
T0-T1 T1-T2 T2-T3 T3-T4
stom
ata
prec
urso
rs-1
day
-1
Stomatal differentiation rate
D
Col-0 spch-5
15%
85%
Do not enterEnter into lineage
70%30%
spch-5
Col-0
A
65%35%
Primary lineagesSecondary lineages
62%38%
spch-5
Col-0
C
Supplemental Figure 7. Orientation of cell division planes in
spch-5 and spch-5 mute-3 stomatal lineages.
Confocal images of 13-day-old adaxial cotyledon epidermis,
showing cell contours with PI (red) and young lineage cells with
GFP (green) expressed from a TMMpro:GFP reporter construct.
mute-3 plants form rosette-like lineages with several small cells
in a regular inward spiral arrangement indicated as a dotted white
line. Only the most recently formed meristemoid shows a strong
TMMpro:GFP expression. mute-3 spch-5 double mutant lineages
also display extra small cells, but arranged in irregular patterns
and of which several express TMMpro:GFP. Note the absence of
stomata due to the lack of the MUTE function. Bars = 50 µm.
mute-3 mute-3 spch-5
mute-3 mute-3 spch-5
TMMpro:GFP TMMpro:GFP
Supplemental Figure 8. Homology-based three-dimensional
structural prediction for the SPCH-5 protein.
Modeled protein structures of SPCH versions. (A) Wild type
SPCH. (B) SPCH-5 predicted from spch-5. The amino acid triad
critical for DNA binding in other bHLH proteins is highlighted
(pink). The wild-type Arg111 substituted by Trp111 in spch-5 is
marked in orange. The hydrogen bond involving this Arg111 is
indicated as a dashed line with the distance in Ångströms (A), but
is lost in the mutant (B).
2.38
His104Glu108
Arg112
Arg111
SPCH
Trp111
SPCH-5
His104Glu108
Arg112
A
B
Supplemental Figure 9. DNA-protein interactions involving
SPCH-5.
(A) Scheme of the domain structure of SPCH and the truncated
SPCHΔ273 version lacking the C-terminal part (the ACT-like or SMF domain). (B) Yeast one-hybrid experiment with the
tandem-repeated G-box sequence as bait for the wild type (WT) or a mutated version (mut). Colored circles indicate LacZ report-
er-normalized expression.
50 aa
bHLH MPKTD
bHLH SPCHMPKTD SMF
SPCHΔ273
A
Bait
TF
No vector
Empty AD vector
SPCH
SPCH-5
SPCHΔ273
PIF4
ICE1
SPCH-5 + ICE1
SPCH + ICE1
normalized value
0 1
B
G-boxWT mut
Supplemental Figure 10. Protein--protein interactions involving
SPCH-5.
(A) to (C) BiFC experiments with transient expression assays in
Nicotiana benthamiana leaves. Image compositions were made
with representative cells showing the recomposed GFP signal
diagnostic for physical interactions between proteins.
SP
CH
SP
CH
-5N
o p
artn
er
ICE1 SCRM2 No partner
GFP BF
Merge100 µm
A
100 µmSP
CH
SPCHB
SP
CHPPP
100 µm
ICE1 SCRM2 No partnerC
Supplemental Figure 11. Phenotypic and protein expression analyses of spch-3 lines complemented with different SPCH versions.
(A) to (C) DIC images of the epidermis of spch-3 plants transformed with translational GFP fusions to SPCH, SPCH-5, or SPCHPPP under
the control of the SPCH promoter. Adaxial (A) and abaxial (B) 23-day-old cotyledons and 10-days-old hypocotyls (C) are shown. Stomata
are colored purple. Stomatal clusters are enclosed into brackets. (D) to (F) Confocal images of the same lines in (A) to (C). Red outlines
are PI-stained cell contours. Images were taken 3 days after sowing. GFP fluorescence marks the expression of the different protein
versions. Adaxial (D) and abaxial (E) cotyledons and hypocotyls (F) are shown. Bars = 100 µm.
Hyp
oco
tyl
Ad
axia
l C
ot.
Ab
axia
l C
ot.
]
SPCHpro:SPCH-GFP/spch-3 SPCH
pro:SPCHPPP-GFP/spch-3SPCH
pro:SPCH-5-GFP/spch-3
A
B
C
D
E
F
spch-2 (DMSO)
spch-2 (BL)
0
5
10
15
20
25
SI (%
)
spch-2
+ D
MSO
spch-2
+BL
n.dC
B
A
Supplemental Figure 12. BL effect on spch-2 stomatal develop-
ment.
(A) and (B) DIC images of the abaxial epidermis of spch-2 in
DMSO (A) and BL (B). (C) Stomatal index quantification of
spch-2 in medium with (purple) and without BL (grey). Error bars
represent SE. n.d denotes absence of statistically significant
differences between mean values (95% confident Student’s t test).
Supplemental Figure 13. Quantitative PCR for microarray validation.
Gene expression data in the microarrays (orange) validated by qRT-PCR (green) for 10 genes related to stomata development or BR
pathway, selected in pairwise comparisons between genotypes and BL treatments. (A) Nontreated spch-5 vs Col-0. (B) Nontreated
SPCHPPP/spch-3 vs Col-0. (C) BL-treated vs control spch-5. (D) BL-treated vs control SPCHPPP/spch-3. UBIQUITIN10 and ACTIN2 served
as reference genes. The Log2-fold change of the qRT-PCR expression data was calculated and represented. The qRT-PCR results were
averaged from three (or two in the case of SPCHPPP/spch-3) independent experiments, with the error bar representing the SE of the mean.
qPCR microarray
Aspch-5+DMSO vs Col-0+DMSO
Log
2(F
C)
TMM EPF2 CPD BASL EPF1 BIN2 ICE1 SCRM2 SPCH SDD10
-2
2
-4
-6
BSPCHPPP/spch-3+DMSO vs Col-0+DMSO
-6
-8
-4
-2
0
2
TMM EPF2 CPD BASL EPF1 BIN2 ICE1 SCRM2 SPCH SDD1
Log
2(F
C)
qPCR microarray
qPCR microarray
C spch-5+BL vs spch-5+DMSO
Log
2(F
C)
TMM EPF2 CPD BASL EPF1 BIN2 ICE1 SCRM2 SPCH SDD10
2
1
-1
-2
qPCR microarray
D SPCHPPP/spch-3+BL vs SPCHPPP/spch-3+DMSO Log
2(F
C)
0
1
-1
TMM EPF2 CPD BASL EPF1 BIN2 ICE1 SCRM2 SPCH SDD1
Supplemental Figure 14. Biological processes overrepresented in the spch-5 DEGs.
Genes differentially expressed in spch-5 as compared to Col-0 were analyzed with Gene Ontology (GO) term enrichment by means of ClueGO. Circles represent GO categories and lines depict relationships between nodes. Only the main categories enriched in DEGs in spch-5 and the involved main nodes are shown. Nodes containing down-regulated genes are in green; nodes containing both up- and down-regulated genes are in grey; no nodes were found with only up-regulated genes. Node size is relative to its P-value (inset). (A) Cell division and expansion. (B) Stomatal and epidermal development. (C) Hormonal responses. (D) Histone kinases
response to organic substance histone H3−S10
phosphorylation
microtubule−based movement
plant epidermis development
response to hormone
microtubule−based process cytokinesis
cell division
stomatal complex development
AB
CD
pV 0.005 - 0.01
pV 0.0005 - 0.005
pV 0.00005 - 0.0005
pV < 0.00005% up-regulated
unspecific terms
100%
50%
100%
50%
% down-regulated
<50%
Node Colour Node Size