title: Low PSI content limits the photoprotection of PSI and PSII in early growth stages of chlorophyll b-deficient wheat mutant lines.
abstract: In vivo analyses of electron and proton transport-related processes as well as photoprotective responses were carried out at different stages of growth in chlorophyll b (Chl b)-deficient mutant lines (ANK-32A and ANK-32B) and wild type (WT) of wheat (Triticum aestivum L.). In addition to a high Chl a-b ratio, ANK mutants had a lower content of photo-oxidizable photosystem I (PSI, P m), and several parameters indicated a low PSI/PSII ratio. Moreover, simultaneous measurements of Chl fluorescence and P700 indicated a shift of balance between redox poise of the PSII acceptor side and the PSII donor side, with preferential reduction of the plastoquinone pool, resulting in an over reduced PSI acceptor side (high Φ NA values). This was the probable reason for PSI inactivation observed in the ANK mutants, but not in WT. In later growth phases, we observed partial relief of "chlorina symptoms," toward WT. Measurements of ΔA 520 decay confirmed that, in early growth stages, the ANK mutants with low PSI content had a limited capacity to build up the transthylakoid proton gradient (ΔpH) needed to trigger non-photochemical quenching (NPQ) and to regulate the electron transport by cytochrome b 6/f. Later, the increase in the PSI/PSII ratio enabled ANK mutants to reach full NPQ, but neither over reduction of the PSI acceptor side nor PSI photoinactivation due to imbalance between the activity of PSII and PSI was mitigated. Thus, our results support the crucial role of proper regulation of linear electron transport in the protection of PSI against photoinhibition. Moreover, the ANK mutants of wheat showing the dynamic developmental changes in the PSI/PSII ratio are presented here as very useful models for further studies.
authors: Department of Plant Physiology, Slovak Agricultural University, Tr. A. Hlinku 2, 949 76, Nitra, Slovak Republic, marian.brestic@uniag.sk.
authors: Marian
authors: M
authors: Brestic
authors: Marek
authors: M
authors: Zivcak
authors: Kristyna
authors: K
authors: Kunderlikova
authors: Oksana
authors: O
authors: Sytar
authors: Hongbo
authors: H
authors: Shao
authors: Hazem M
authors: HM
authors: Kalaji
authors: Suleyman I
authors: SI
authors: Allakhverdiev
mesh_terms: D002734:Chlorophyll / Q000235:genetics* / Q000378:metabolism; D004579:Electron Transport; D005453:Fluorescence; D008027:Light; D009154:Mutation; D010084:Oxidation-Reduction; D010788:Photosynthesis; D045331:Photosystem I Protein Complex / Q000378:metabolism* / Q000528:radiation effects; D045332:Photosystem II Protein Complex / Q000378:metabolism* / Q000528:radiation effects; D010971:Plastoquinone / Q000378:metabolism*; D011522:Protons; D014908:Triticum / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects
chemical_list: D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D011522:Protons; D002734:Chlorophyll; C037184:chlorophyll b; D010971:Plastoquinone
references: Proc Natl Acad Sci U S A. 2002 Jul 23;99(15):10209-14
references: 12119384
references: Annu Rev Plant Physiol Plant Mol Biol. 1999 Jun;50:601-639
references: 15012221
references: Trends Plant Sci. 2003 Jan;8(1):27-32
references: 12523997
references: Biochim Biophys Acta. 2012 Aug;1817(8):1490-8
references: 22609146
references: Photosynth Res. 2014 Nov;122(2):121-58
references: 25119687
references: Physiol Plant. 2011 May;142(1):56-64
references: 21128947
references: Biochim Biophys Acta. 2002 Dec 2;1556(2-3):239-46
references: 12460682
references: Plant Cell Physiol. 2014 May;55(5):990-1004
references: 24553846
references: Planta. 2005 Apr;221(1):5-8
references: 15782347
references: Nature. 2004 Jun 3;429(6991):579-82
references: 15175756
references: Plant Cell Environ. 2009 Mar;32(3):209-19
references: 19021886
references: Planta. 2003 Nov;218(1):107-14
references: 12883889
references: Plant Physiol. 2011 Jan;155(1):70-8
references: 21078862
references: Plant Physiol. 1995 Mar;107(3):873-83
references: 7748263
references: Curr Opin Plant Biol. 2000 Dec;3(6):455-60
references: 11074375
references: Photosynth Res. 1995 May;44(1-2):81-91
references: 24307028
references: Biochim Biophys Acta. 2012 May;1817(5):770-9
references: 22342617
references: Photosynth Res. 1996 May;48(1-2):171-87
references: 24271297
references: Plant Cell Physiol. 2010 Dec;51(12):1951-63
references: 21068108
references: Biochim Biophys Acta. 2014 Jan;1837(1):210-5
references: 24161359
references: Photosynth Res. 2000;66(1-2):145-58
references: 16228416
references: Annu Rev Plant Biol. 2008;59:89-113
references: 18444897
references: FEBS J. 2005 Feb;272(4):892-902
references: 15691324
references: Curr Opin Biotechnol. 2014 Apr;26:25-30
references: 24679254
references: Photosynth Res. 2004 Feb;79(2):209
references: 16228395
references: Biochim Biophys Acta. 1979 Oct 10;548(1):128-38
references: 486438
references: J Photochem Photobiol B. 2004 Jul 19;75(1-2):41-50
references: 15246349
references: Photosynth Res. 2014 Mar;119(3):339-54
references: 24445618
references: Photosynth Res. 2004;82(1):17-33
references: 16228610
references: Photosynth Res. 1993 Nov;38(2):141-51
references: 24317910
references: J Photochem Photobiol B. 2002 Jul;67(3):194-200
references: 12167319
references: Plant Physiol. 1994 Feb;104(2):639-48
references: 8159789
references: J Photochem Photobiol B. 2014 Aug;137:107-15
references: 24508481
references: Photosynth Res. 2005 Jun;84(1-3):145-51
references: 16049767
references: Biochim Biophys Acta. 2012 Aug;1817(8):1127-33
references: 22387427
references: Plant Cell Physiol. 2014 Jun;55(6):1184-93
references: 24793753
references: Photochem Photobiol. 2003 Mar;77(3):284-91
references: 12685656
references: Biochim Biophys Acta. 2011 Mar;1807(3):384-9
references: 21118673
references: Plant Physiol. 1996 Oct;112(2):821-32
references: 8883392
references: Proc Natl Acad Sci U S A. 2011 Aug 9;108(32):13317-22
references: 21784980
references: Plant Physiol Biochem. 2014 Aug;81:74-83
references: 24491798
references: Plant Physiol. 2012 Dec;160(4):1896-910
references: 23033142
references: J Exp Bot. 2012 Feb;63(4):1637-61
references: 22371324
references: New Phytol. 2006;172(1):11-21
references: 16945085
references: Physiol Mol Biol Plants. 2008 Jul;14(3):205-15
references: 23572888
references: Sensors (Basel). 2010;10 (11):10040-68
references: 22163456
references: Plant Cell Physiol. 2005 Apr;46(4):629-37
references: 15701657
references: J Exp Bot. 2005 Jan;56(411):395-406
references: 15533877
references: Photosynth Res. 2013 Nov;117(1-3):529-46
references: 23860828
references: Plant Physiol Biochem. 2014 Aug;81:135-42
references: 24637130
references: Dokl Biol Sci. 2005 Nov-Dec;405:472-3
references: 16485648
references: PLoS One. 2013;8(3):e59433
references: 23527194
references: Biochim Biophys Acta. 2014 Jun;1837(6):835-48
references: 24530357
references: Nature. 2000 Jan 27;403(6768):391-5
references: 10667783
references: Photosynth Res. 2013 Mar;114(3):189-206
references: 23196877
references: Annu Rev Plant Biol. 2009;60:239-60
references: 19575582
references: Photosynth Res. 2010 Feb;103(2):79-95
references: 20039131
references: Plant Cell. 2012 Jul;24(7):2934-48
references: 22822205
references: Plant Cell Environ. 2007 Sep;30(9):1041-51
references: 17661746
references: Water Res. 2003 May;37(9):1983-90
references: 12691882
references: Philos Trans R Soc Lond B Biol Sci. 2012 Dec 19;367(1608):3486-93
references: 23148275
references: Biochim Biophys Acta. 2011 Jan;1807(1):22-9
references: 20840840
references: Photosynth Res. 1990 Sep;25(3):295-8
references: 24420359