Abstract
The effect of temperature on the photosynthetic machinery is crucial for the fundamental understanding of plant physiology and the bioengineering of heat-tolerant varieties. In our study, Arabidopsis thaliana was exposed to mild (40 °C), short-term heat stress in the dark to evaluate the heat-triggered phosphorylation and migration of light harvesting complex (LHC) II in both wild-type (wt) and mutant lacking STN7 kinase. The 77 K emission spectra revealed an increase in PSI relative to PSII emission similar to increases observed in light-induced state I to state II transitions in wt but not in stn7 mutant. Immunoblotting results indicated that the major LHCII was phosphorylated at threonine sites under heat stress in wt plants but not in the mutant. These results support the proposition that mild heat stress triggers state transitions in the dark similar to light-induced state transitions, which involve phosphorylation of LHCII by STN7 kinase. Pre-treatment of Arabidopsis leaves with inhibitor DBMIB, altered the extent of LHCII phosphorylation and PSI fluorescence emission suggests that activation of STN7 kinase may be dependent on Cyt b6/f under elevated temperatures in dark. Furthermore, fast Chl a transient of temperature-exposed leaves of wt showed a decrease in the Fv/Fm ratio due to both an increase in Fo and a decrease in Fm. In summary, our findings indicate that a mild heat treatment (40 °C) induces state transitions in the dark resulting in the migration of phosphorylated LHCII from the grana to the stroma region.
| Original language | English |
|---|---|
| Pages (from-to) | 1177-1184 |
| Number of pages | 8 |
| Journal | Biochimica et Biophysica Acta - Bioenergetics |
| Volume | 1807 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - Sep 1 2011 |
| Externally published | Yes |
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Keywords
- Arabidopsis thaliana
- Elevated temperature
- Photosystems
- PQ pool
- State transition
- STN7 kinase
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Cell Biology
Cite this
Moderate heat stress induces state transitions in Arabidopsis thaliana. / Nellaepalli, Sreedhar; Mekala, Nageswara Rao; Zsiros, Otto; Mohanty, Prasanna; Subramanyam, Rajagopal.
In: Biochimica et Biophysica Acta - Bioenergetics, Vol. 1807, No. 9, 01.09.2011, p. 1177-1184.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Moderate heat stress induces state transitions in Arabidopsis thaliana
AU - Nellaepalli, Sreedhar
AU - Mekala, Nageswara Rao
AU - Zsiros, Otto
AU - Mohanty, Prasanna
AU - Subramanyam, Rajagopal
PY - 2011/9/1
Y1 - 2011/9/1
N2 - The effect of temperature on the photosynthetic machinery is crucial for the fundamental understanding of plant physiology and the bioengineering of heat-tolerant varieties. In our study, Arabidopsis thaliana was exposed to mild (40 °C), short-term heat stress in the dark to evaluate the heat-triggered phosphorylation and migration of light harvesting complex (LHC) II in both wild-type (wt) and mutant lacking STN7 kinase. The 77 K emission spectra revealed an increase in PSI relative to PSII emission similar to increases observed in light-induced state I to state II transitions in wt but not in stn7 mutant. Immunoblotting results indicated that the major LHCII was phosphorylated at threonine sites under heat stress in wt plants but not in the mutant. These results support the proposition that mild heat stress triggers state transitions in the dark similar to light-induced state transitions, which involve phosphorylation of LHCII by STN7 kinase. Pre-treatment of Arabidopsis leaves with inhibitor DBMIB, altered the extent of LHCII phosphorylation and PSI fluorescence emission suggests that activation of STN7 kinase may be dependent on Cyt b6/f under elevated temperatures in dark. Furthermore, fast Chl a transient of temperature-exposed leaves of wt showed a decrease in the Fv/Fm ratio due to both an increase in Fo and a decrease in Fm. In summary, our findings indicate that a mild heat treatment (40 °C) induces state transitions in the dark resulting in the migration of phosphorylated LHCII from the grana to the stroma region.
AB - The effect of temperature on the photosynthetic machinery is crucial for the fundamental understanding of plant physiology and the bioengineering of heat-tolerant varieties. In our study, Arabidopsis thaliana was exposed to mild (40 °C), short-term heat stress in the dark to evaluate the heat-triggered phosphorylation and migration of light harvesting complex (LHC) II in both wild-type (wt) and mutant lacking STN7 kinase. The 77 K emission spectra revealed an increase in PSI relative to PSII emission similar to increases observed in light-induced state I to state II transitions in wt but not in stn7 mutant. Immunoblotting results indicated that the major LHCII was phosphorylated at threonine sites under heat stress in wt plants but not in the mutant. These results support the proposition that mild heat stress triggers state transitions in the dark similar to light-induced state transitions, which involve phosphorylation of LHCII by STN7 kinase. Pre-treatment of Arabidopsis leaves with inhibitor DBMIB, altered the extent of LHCII phosphorylation and PSI fluorescence emission suggests that activation of STN7 kinase may be dependent on Cyt b6/f under elevated temperatures in dark. Furthermore, fast Chl a transient of temperature-exposed leaves of wt showed a decrease in the Fv/Fm ratio due to both an increase in Fo and a decrease in Fm. In summary, our findings indicate that a mild heat treatment (40 °C) induces state transitions in the dark resulting in the migration of phosphorylated LHCII from the grana to the stroma region.
KW - Arabidopsis thaliana
KW - Elevated temperature
KW - Photosystems
KW - PQ pool
KW - State transition
KW - STN7 kinase
UR - http://www.scopus.com/inward/record.url?scp=79960562176&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79960562176&partnerID=8YFLogxK
U2 - 10.1016/j.bbabio.2011.05.016
DO - 10.1016/j.bbabio.2011.05.016
M3 - Article
C2 - 21640068
AN - SCOPUS:79960562176
VL - 1807
SP - 1177
EP - 1184
JO - Biochimica et Biophysica Acta - Bioenergetics
JF - Biochimica et Biophysica Acta - Bioenergetics
SN - 0005-2728
IS - 9
ER -