Presented at Plant Genomics and Gene Editing Congress: Asia. For more information visit: www.global-engage.com Potassium is an essential macronutrient, but cesium has no nutritional value for plants. However plants absorb and accumulate certain levels of cesium. Cesium and potassium share similar chemical properties, and it is known that cesium accumulation in plants through potassium uptake system. In this presentation, plant responses to cesium and potassium will be discussed focusing on the alteration of metabolites.

1. Understanding the plant response to
cesium and potassium using metabolomics
profiling and chemical screening
Ryoung Shin
RIKEN Center for Sustainable Resource Science
April-11th-2017

2. Background

3. SOS1
Na+
PhloemXylem
H+
K+
KUPs
HAK5
K+
SKOR
K+ GORK
K+
AKT1&
KC1
K+AKT2/3
AKT2/3
K+KAT2
K+
HKT2
Na+
K+
Na+/K+
H+
CHXs
CNGCs
LCT1
GORK
NH4
+
Guard cell
Na+/K+
K+
Na+/K+
GLRs
HKT1Na+
KAT1
KAT2K+
CHX20
K+
H+
K+
Na+HKT1
SOS1
Na+
SOS1
K+
KEAs
H+
Potassium
channels/
transporters
Plants utilize the
potassium uptake
system for the
cesium uptake

4. Looking for different cesium accumulated
plants
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+ K+
K+K+
K+
K+
K+K+
K+K+K+
K+
K+
K+K+
K+
K+
K+
K+K+ K+
K+
K+K+K+
K+
K+
K+
K+ K+
K+
K+
K+
K+
K+
K+
K+
K+
K+ K+
K+
Cs+
K+
K+ K+
K+
Cs+
Cs+
Cs+
Cs+
Cs+
K+
K+
K+Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
K+
K+
K+ K+
K+
Cs+
K+
K+ K+
K+ Cs+
Wild type plant overexpression plants overexpression plants
Cs+
Cs+

5. 0
10
20
30
40
50
no Cs
Col-0
Cs
Col-0
no Cs
mut
Cs
mut
no Cs
OX1
Cs
OX1
no Cs
OX2
Cs
OX2
nmolCs/mgdw
**
Cs+ - +
Col-0
- +
mutant
- +
OX1
- +
OX2
0
10
20
30
40
50
no Cs
Col-0
Cs
Col-0
no Cs
mut1
Cs
mut1
no Cs
mut2
Cs
mut2
no Cs
mut3
Cs
mut3
no Cs
mut4
Cs
mut4
nmolCs/mgdw
*
**
*
- +
mutant2
- +
mutant1
- +
Col-0
Cs+ - +
mutant3
- +
mutant4
Looking for different cesium accumulated
plants

6. Screening chemicals which change the
cesium uptake ability in plants
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+ K+
K+K+
K+
K+
K+K+
K+K+K+
K+
K+
K+K+
K+
K+
K+
K+K+ K+
K+
K+K+K+
K+
K+
K+
K+ K+
K+
K+
K+
K+
K+
K+
K+
K+
K+ K+
K+
K+
K+ K+
K+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
K+
K+
K+Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
Cs+
K+
K+
K+ K+
K+
Cs+
K+
K+ K+
K+
Cs+Cs+ Cs+
adding chemical
= lower Cs uptake
Cs+
Cs+
Cs+
adding chemical
= higher Cs uptake

7. Scheme of chemical screening for identifying
new chemical for cesium uptake

8. Chemical screening
0.5 mM KCl 0.5 mM KCl +
0.4 mM CsCl +
1 mM chemical
0.5 mM KCl +
0.4 mM CsCl
Score Number %
0: no difference from Cs control 9755 97.55
1: one or two seedling(s) surviving 68 0.68
2: slightly healthier than Cs control 150 1.5
3: obviously healthier than Cs control 25 0.25
4: as healthy as K control 2 0.02

9. Phenotypic analysis of candidate chemicals

10. CsTolen A reduces Cs uptake and enhances
Cs tolerance

11. CsTolen A binds to Cs ion

12. Derivatives of CsTolen A don’t reduce Cs
uptake and enhance Cs tolerance

13. CsTolen A reduces Cs uptake in soil
grown plants

14. Metabolic profiling
• In order to understand which metabolic pathways
involve in potassium/cesium response in plants
• Arabidopsis seedlings were grown and harvested
leaves and roots
• GC/MS and LC/MS were performed
25uM KCl 0.5mM KCl 1.75mM KCl
0mM CsCl low K suboptimal K optimal K
0.3mM CsCl high Cs high Cs high Cs
1.75 mM KCl
1.75 mM KCl + 0.3 mM CsCl
0.5 mM KCl
0.5 mM KCl + 0.3 mM CsCl
25 mM KCl
25 mM KCl + 0.3 mM CsCl

15. -6
-4
-2
0
2
4
6
-9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9
Untargeted profiling by LC-Q-TOF-MS
Positive ion mode, shoots
0.5 mM K+Cs
1.75 mM K+Cs
0.5 mM K
1.75 mM K
25 mM K
PC1 43.6%
PC227.1%
-8
-6
-4
-2
0
2
4
6
8
-10 0 10
Untargeted profiling by LC-Q-TOF-MS
Positive ion mode, roots
PC216.9%
PC1 54.3%
25 mM K+Cs
1.75 mM K
1.75 mM K+Cs
0.5 mM K
0.5 mM K+Cs 25 mM K
-10
0
10
-10 0 10
Untargeted profiling by LC-Q-TOF-MS
Negative ion mode, shoots
PC1 41.0%
PC230.9%
0.5 mM K+Cs
1.75 mM K+Cs
0.5 mM K1.75 mM K
25 mM K
-10
-5
0
5
10
-20 -10 0 10 20
PC213.6%
Untargeted profiling by LC-Q-TOF-MS
Negative ion mode, roots
25 mM K+Cs
25 mM K
0.5 mM K+Cs
1.75 mM K+Cs
0.5 mM K
1.75 mM K
PCA analysis of metabolic profiling
(Secondary metabolites)

16. PCA analysis of metabolic profiling
(Primary metabolites)
Root Shoot

17. The level of amino acids were increased
by cesium treatment
amino acid K K + Cs
Alanine 145 1400
Asparagine 4.39 10.4
Cysteine 0.43 1.42
Glutamine 631 4690
Glycine 6.21 17.7
Isoleucine 1.06 4.36
Leucine 15.3 31.5
Lysine 0.44 1.22
Methionine 2970 4110
Phenylalanine 8.88 31.4
Proline 5.50 64.1
Serine 176 3640
Threonine 85.5 490
Valine 26.5 101
amino acid K K + Cs
Alanine 265 494
Asparagine 9.92 20.2
Cysteine 0.82 2.45
Glutamine 1990 6220
Proline 22.4 40.1
Serine 1150 2050
Threonine 1200 3440
Shoot Root

18. Methyl Cysteinate application resulted in
increasing cesium accumulation in plants
O
NH2
O
SH CH3
Methyl Cysteinate
1.75K
0.3Cs
1.75K
+cys
0.3Cs+
cys
0
10
20
30
40
***
nmolCs/mgDW

19. Cysteine and its derivatives
L-Cysteine ethyl ester hydrochloride
N-Acetyl-L-cysteine

20. Cesium binds with methyl
cysteinate
Methyl Cysteinate
Cysteine
Methyl Cys
Cys

21. Summary
- In order to find small molecules which alter Cs+ uptake ability in plants,
20,000 chemicals were screened with two different strategies.
- Candidate chemicals which enhanced Cs+ tolerance or enhanced Cs+
accumulation in plants were chosen and the further characterization of
them were performed using theoretical modelling and physiological
analysis.
- CsTolen A reduced the Cs+ accumulation in plants via Cs+ binding
outside of plants.
- The levels of many amino acid including cysteine were increased by
Cs+ treatments
- Cysteine and its derivative, methyl cysteinate function as Cs+
accumulators.

22. Acknowledgements
Lab members
Dr. Eri Adams
Dr. Aya Hayaishi-Satoh
Dr. Minwoo Han
Ms. Takae MIYAZAKI
Mr. Hajime Takiguchi
Mr. Tsuzumi Mito
• Supported by MAFF & RIKEN
Collaborators
-Dr. Khandelia; University of South Denmark
-Dr. Saito, RIKEN