Effect of light on the rearrangements of PSI super-and megacomplexes in the non-appressed thylakoid domains of maize mesophyll chloroplasts
| Autor: | Aleksandra Urban, Paweł Rogowski, Wioleta Wasilewska-Dębowska, Elżbieta Romanowska |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
0301 basic medicine Chloroplasts Light Light-Harvesting Protein Complexes Plant Science Biology Thylakoids Zea mays 01 natural sciences Dissociation (chemistry) 03 medical and health sciences chemistry.chemical_compound Genetics Photosystem Photosystem I Protein Complex Photosystem II Protein Complex Far-red General Medicine Darkness Plant Leaves Chloroplast 030104 developmental biology Monomer chemistry Thylakoid Biophysics Mesophyll Cells Agronomy and Crop Science Light stress 010606 plant biology & botany |
| Zdroj: | Plant Science. 301:110655 |
| ISSN: | 0168-9452 |
| DOI: | 10.1016/j.plantsci.2020.110655 |
| Popis: | We demonstrated the existence of PSI-LHCI-LHCII-Lhcb4 supercomplexes and PSI-LHCI-PSII-LHCII megacomplexes in the stroma lamellae and grana margins of maize mesophyll chloroplasts; these complexes consist of different LHCII trimers and monomer antenna proteins per PSI photocentre. These complexes are formed in both low (LL) and high (HL) light growth conditions, but with different contents. We attempted to identify the components and structure of these complexes in maize chloroplasts isolated from the leaves of low and high light-grown plants after darkness and transition to far red (FR) light of high intensity. Exposition of plants from high and low light growth condition on FR light induces different rearrangements in the composition of super- and megacomplexes. During FR light exposure, in plants from LL, the PSI-LHCI-LHCII-Lhcb4 supercomplex dissociates into free LHCII-Lhcb4 and PSI-LHCI complexes, and these complexes associate with the PSII monomer. This process occurs differently in plants from HL. Exposition to FR light causes dissociation of both PSI-LHCI-LHCII-Lhcb4 supercomplexes and PSI-PSII megacomplexes. These results suggest a different function of super- and megacomplex organization than the classic state transitions model, which assumes that the movement of LHCII trimers in the thylakoid membraneis considered as a mechanism for balancing light absorption between the two photosystems in light stress. The behavior of the complexes described in this article does not seem to be well explained by this model, i.e., it does not seem likely that the primary purpose of these megacomplexes dynamics is to balance excitation pressure. Rather, as stated in this article, it seems to indicate a role of these complexes for PSI in excitation quenching and for PSII in turnover. |
| Databáze: | OpenAIRE |
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