Non-photochemical quenching-dependent acclimation and thylakoid organization of Chlamydomonas reinhardtii to high light stress

Srilatha Nama, Sai Kiran Madireddi, Ranay Mohan Yadav, S. Rajagopal

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Light is essential for all photosynthetic organisms while an excess of it can lead to damage mainly the photosystems of the thylakoid membrane. In this study, we have grown Chlamydomonas reinhardtii cells in different intensities of high light to understand the photosynthetic process with reference to thylakoid membrane organization during its acclimation process. We observed, the cells acclimatized to long-term response to high light intensities of 500 and 1000 µmol m−2 s−1 with faster growth and more biomass production when compared to cells at 50 µmol m−2 s−1 light intensity. The ratio of Chl a/b was marginally decreased from the mid-log phase of growth at the high light intensity. Increased level of zeaxanthin and LHCSR3 expression was also found which is known to play a key role in non-photochemical quenching (NPQ) mechanism for photoprotection. Changes in photosynthetic parameters were observed such as increased levels of NPQ, marginal change in electron transport rate, and many other changes which demonstrate that cells were acclimatized to high light which is an adaptive mechanism. Surprisingly, PSII core protein contents have marginally reduced when compared to peripherally arranged LHCII in high light-grown cells. Further, we also observed alterations in stromal subunits of PSI and low levels of PsaG, probably due to disruption of PSI assembly and also its association with LHCI. During the process of acclimation, changes in thylakoid organization occurred in high light intensities with reduction of PSII supercomplex formation. This change may be attributed to alteration of protein–pigment complexes which are in agreement with circular dichoism spectra of high light-acclimatized cells, where decrease in the magnitude of psi-type bands indicates changes in ordered arrays of PSII–LHCII supercomplexes. These results specify that acclimation to high light stress through NPQ mechanism by expression of LHCSR3 and also observed changes in thylakoid protein profile/supercomplex formation lead to low photochemical yield and more biomass production in high light condition.

Original languageEnglish
Pages (from-to)1-14
Number of pages14
JournalPhotosynthesis Research
DOIs
Publication statusAccepted/In press - Jul 7 2018

Fingerprint

Chlamydomonas reinhardtii
Thylakoids
Acclimatization
thylakoids
Quenching
acclimation
Light
High intensity light
light intensity
cells
biomass production
Biomass
Membranes
photostability
zeaxanthin
autotrophs
electron transfer
protein content
Proteins
Growth

Keywords

  • Chlamydomonas reinhardtii
  • Energy transfer
  • High light stress
  • Light-harvesting complexes
  • Photosystems
  • Reaction centers
  • Thylakoid organization

ASJC Scopus subject areas

  • Biochemistry
  • Plant Science
  • Cell Biology

Cite this

Non-photochemical quenching-dependent acclimation and thylakoid organization of Chlamydomonas reinhardtii to high light stress. / Nama, Srilatha; Madireddi, Sai Kiran; Yadav, Ranay Mohan; Rajagopal, S.

In: Photosynthesis Research, 07.07.2018, p. 1-14.

Research output: Contribution to journalArticle

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