Abstract
Mg-chelatase H subunit (CHLH) is a multifunctional protein involved in chlorophyll synthesis, plastid-to-nucleus retrograde signaling, and ABA perception. However, whether CHLH acts as an actual ABA receptor remains controversial. Here we present evidence that CHLH affects ABA signaling in stomatal guard cells but is not itself an ABA receptor. We screened ethyl methanesulfonate-treated Arabidopsis thaliana plants with a focus on stomatal aperture-dependent water loss in detached leaves and isolated a rapid transpiration in detached leaves 1 (rtl1) mutant that we identified as a novel missense mutant of CHLH. The rtl1 and CHLH RNAi plants showed phenotypes in which stomatal movements were insensitive to ABA, while the rtl1 phenotype showed normal sensitivity to ABA with respect to seed germination and root growth. ABA-binding analyses using 3H-labeled ABA revealed that recombinant CHLH did not bind ABA, but recombinant pyrabactin resistance 1, a reliable ABA receptor used as a control, showed specific binding. Moreover, we found that the rtl1 mutant showed ABA-induced stomatal closure when a high concentration of extracellular Ca2+ was present and that a knockout mutant of Mg-chelatase I subunit (chli1) showed the same ABA-insensitive phenotype as rtl1. These results suggest that the Mg-chelatase complex as a whole affects the ABA-signaling pathway for stomatal movements.
| Original language | English |
|---|---|
| Pages (from-to) | 527-538 |
| Number of pages | 12 |
| Journal | Journal of Plant Research |
| Volume | 124 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - Jul 2011 |
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Keywords
- ABA
- Ca
- Mg-chelatase H subunit
- Receptor
- Signal transduction
- Stomatal guard cell
ASJC Scopus subject areas
- Plant Science
Cite this
Mg-chelatase H subunit affects ABA signaling in stomatal guard cells, but is not an ABA receptor in Arabidopsis thaliana. / Tsuzuki, Tomo; Takahashi, Koji; Inoue, Shin ichiro; Okigaki, Yukiko; Tomiyama, Masakazu; Hossain, Mohammad Anowar; Shimazaki, Ken ichiro; Murata, Yoshiyuki; Kinoshita, Toshinori.
In: Journal of Plant Research, Vol. 124, No. 4, 07.2011, p. 527-538.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Mg-chelatase H subunit affects ABA signaling in stomatal guard cells, but is not an ABA receptor in Arabidopsis thaliana
AU - Tsuzuki, Tomo
AU - Takahashi, Koji
AU - Inoue, Shin ichiro
AU - Okigaki, Yukiko
AU - Tomiyama, Masakazu
AU - Hossain, Mohammad Anowar
AU - Shimazaki, Ken ichiro
AU - Murata, Yoshiyuki
AU - Kinoshita, Toshinori
PY - 2011/7
Y1 - 2011/7
N2 - Mg-chelatase H subunit (CHLH) is a multifunctional protein involved in chlorophyll synthesis, plastid-to-nucleus retrograde signaling, and ABA perception. However, whether CHLH acts as an actual ABA receptor remains controversial. Here we present evidence that CHLH affects ABA signaling in stomatal guard cells but is not itself an ABA receptor. We screened ethyl methanesulfonate-treated Arabidopsis thaliana plants with a focus on stomatal aperture-dependent water loss in detached leaves and isolated a rapid transpiration in detached leaves 1 (rtl1) mutant that we identified as a novel missense mutant of CHLH. The rtl1 and CHLH RNAi plants showed phenotypes in which stomatal movements were insensitive to ABA, while the rtl1 phenotype showed normal sensitivity to ABA with respect to seed germination and root growth. ABA-binding analyses using 3H-labeled ABA revealed that recombinant CHLH did not bind ABA, but recombinant pyrabactin resistance 1, a reliable ABA receptor used as a control, showed specific binding. Moreover, we found that the rtl1 mutant showed ABA-induced stomatal closure when a high concentration of extracellular Ca2+ was present and that a knockout mutant of Mg-chelatase I subunit (chli1) showed the same ABA-insensitive phenotype as rtl1. These results suggest that the Mg-chelatase complex as a whole affects the ABA-signaling pathway for stomatal movements.
AB - Mg-chelatase H subunit (CHLH) is a multifunctional protein involved in chlorophyll synthesis, plastid-to-nucleus retrograde signaling, and ABA perception. However, whether CHLH acts as an actual ABA receptor remains controversial. Here we present evidence that CHLH affects ABA signaling in stomatal guard cells but is not itself an ABA receptor. We screened ethyl methanesulfonate-treated Arabidopsis thaliana plants with a focus on stomatal aperture-dependent water loss in detached leaves and isolated a rapid transpiration in detached leaves 1 (rtl1) mutant that we identified as a novel missense mutant of CHLH. The rtl1 and CHLH RNAi plants showed phenotypes in which stomatal movements were insensitive to ABA, while the rtl1 phenotype showed normal sensitivity to ABA with respect to seed germination and root growth. ABA-binding analyses using 3H-labeled ABA revealed that recombinant CHLH did not bind ABA, but recombinant pyrabactin resistance 1, a reliable ABA receptor used as a control, showed specific binding. Moreover, we found that the rtl1 mutant showed ABA-induced stomatal closure when a high concentration of extracellular Ca2+ was present and that a knockout mutant of Mg-chelatase I subunit (chli1) showed the same ABA-insensitive phenotype as rtl1. These results suggest that the Mg-chelatase complex as a whole affects the ABA-signaling pathway for stomatal movements.
KW - ABA
KW - Ca
KW - Mg-chelatase H subunit
KW - Receptor
KW - Signal transduction
KW - Stomatal guard cell
UR - http://www.scopus.com/inward/record.url?scp=79959895949&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79959895949&partnerID=8YFLogxK
U2 - 10.1007/s10265-011-0426-x
DO - 10.1007/s10265-011-0426-x
M3 - Article
VL - 124
SP - 527
EP - 538
JO - Journal of Plant Research
JF - Journal of Plant Research
SN - 0918-9440
IS - 4
ER -