Faraloni Cecilia, Touloupakis Eleftherios, Torzillo Giuseppe
Istituto per la Bioeconomia, Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, Sesto Fiorentino, 50019 Firenze, Italy.
Istituto di Ricerca sugli Ecosistemi Terrestri, Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, Sesto Fiorentino, 50019 Firenze, Italy.
Microorganisms. 2024 Nov 8;12(11):2264. doi: 10.3390/microorganisms12112264.
Dark anaerobiosis promotes the acidification of the thylakoid lumen and a reduction in the plastoquinone (PQ) pool. The relationship between the reduction in the PQ pool in the dark and the induction of the xanthophyll cycle under high light stress was investigated in .
To achieve a comprehensive oxidative/reductive (aerobic/anaerobic conditions) state of the PQ pool, cultures were bubbled with air or nitrogen for 4 h. To induce the xanthophyll cycle, the cultures were then irradiated with 1200 µmol m s white light for 1 h.
The anaerobic cultures exhibited a stronger induction of the xanthophyll cycle with a 3.4-fold higher de-epoxidation state than the aerobic cultures. Chlorophyll fluorescence measurements showed that this response was influenced by the previous redox state of the PQ pool, and that dark anaerobiosis triggers physiological responses, such as exposure to high light. Thus, the photosynthetic apparatus in anaerobic cultures was already alerted, at the moment of high light exposure, to give an appropriate response to the stress with a stronger induction of the xanthophyll cycle than in aerobic cultures.
Our results provide new information on the importance of the redox signaling pathway and highlight the importance of the reductive conditions of the PQ pool in regulating the physiological responses of photosynthetic organisms to stress.
黑暗厌氧环境会促进类囊体腔酸化以及质体醌（PQ）库的减少。本研究调查了黑暗中PQ库的减少与高光胁迫下叶黄素循环诱导之间的关系。
为使PQ库达到全面的氧化/还原（需氧/厌氧条件）状态，向培养物中通入空气或氮气4小时。为诱导叶黄素循环，随后用1200 μmol m⁻² s⁻¹的白光照射培养物1小时。
厌氧培养物中叶黄素循环的诱导作用更强，脱环氧化状态比需氧培养物高3.4倍。叶绿素荧光测量表明，这种反应受PQ库先前的氧化还原状态影响，且黑暗厌氧环境会触发生理反应，如暴露于高光下。因此，在高光暴露时，厌氧培养物中的光合机构已做好准备，以比需氧培养物更强的叶黄素循环诱导作用对胁迫做出适当反应。
我们的结果提供了关于氧化还原信号通路重要性的新信息，并突出了PQ库还原条件在调节光合生物对胁迫的生理反应中的重要性。
