Photorespiration Coupled With CO2 Assimilation Protects Photosystem I From Photoinhibition Under Moderate Poly(Ethylene Glycol)-Induced Osmotic Stress in Rice
Autor: | Amane Makino, Shinya Wada, Yuji Suzuki, Chikahiro Miyake |
---|---|
Jazyk: | angličtina |
Rok vydání: | 2020 |
Předmět: |
0106 biological sciences
0301 basic medicine Photoinhibition Rubisco photorespiration Osmotic shock Photosystem II photosystem I Plant Science macromolecular substances lcsh:Plant culture Photosystem I Photosynthesis 01 natural sciences 03 medical and health sciences lcsh:SB1-1110 Original Research P700 biology Chemistry rice RuBisCO fungi food and beverages photosystem II 030104 developmental biology Biophysics biology.protein Photorespiration osmotic stress CO2 assimilation 010606 plant biology & botany |
Zdroj: | Frontiers in Plant Science, Vol 11 (2020) Frontiers in Plant Science |
Popis: | Photorespiration coupled with CO2 assimilation is thought to act as a defense system against photoinhibition caused by osmotic stress. In the present study, we examined whether such a mechanism is operative for the protection of photosystem I (PSI) in rice (Oryza sativa L.) including transgenic plants with decreased and increased Rubisco content (RBCS-antisense and RBCS-sense plants, respectively). All plants were hydroponically grown and moderate osmotic stress was imposed using hydroponic culture solutions containing poly(ethylene glycol) (PEG) at 16% or 20% (w/v) for 2 d. In wild-type plants, the rates of CO2 assimilation (A) were significantly decreased by the PEG treatment, whereas the photorespiration activity estimated from the rates of electron transport in photosystem II (PSII) and A were not affected. The maximal quantum efficiency of PSII (F v/F m) and the maximal activity of PSI (P m) were also not affected. In RBCS-antisense plants, A and the estimated photorespiration activity were considerably lower than those in wild-type plants in the presence or absence of the PEG treatment. P m and both F v/F m and P m decreased in the 16% PEG-treated and 20% PEG-treated RBCS-antisense plants, respectively. Thus, the decrease in Rubisco content led to the photoinhibition of PSI and PSII, indicating the importance of photorespiration coupled with CO2 assimilation for the protection of PSI from moderate PEG-induced osmotic stress. It was also shown that PSI was more sensitive to osmotic stress than PSII. In the PEG-treated wild-type and RBCS-antisense plants, osmotic-stress responses of the photosynthetic electron transport reactions upstream of PSI led to the oxidation of P700, which is thought to prevent PSI from over-reduction. Although such a defense system operated, it was not sufficient for the protection of PSI in RBCS-antisense plants. In addition, there were no large differences in the parameters measured between wild-type and RBCS-sense plants, as overproduction of Rubisco did not increase photorespiration activity. |
Databáze: | OpenAIRE |
Externí odkaz: |