Role of cyclic and pseudo‐cyclic electron transport in response to dynamic light changes in Physcomitrella patens. (18th December 2018)

• Record Type: Journal Article
• Authors: Storti, Mattia; Alboresi, Alessandro; Gerotto, Caterina; Aro, Eva‐Mari; Finazzi, Giovanni; Morosinotto, Tomas
• Is Part Of: Plant, cell and environment. Volume 42:Number 5(2019)
• Page Start: 1590
• Page End: 1602
• Publication Date: 2018-12-18
• Subjects: Bryophyta -- energy metabolism -- evolution, molecular -- photoprotection -- photosynthesis -- photosynthetic reaction center complex proteins; Plant physiology -- Periodicals; Plant cells and tissues -- Periodicals; Plant communities -- Periodicals; 581.105
• DOI: 10.1111/pce.13493
• Languages: English
• ISSNs: 0140-7791

Abstract

Abstract: Photosynthetic organisms support cell metabolism by harvesting sunlight and driving the electron transport chain at the level of thylakoid membranes. Excitation energy and electron flow in the photosynthetic apparatus is continuously modulated in response to dynamic environmental conditions. Alternative electron flow around photosystem I plays a seminal role in this regulation contributing to photoprotection by mitigating overreduction of the electron carriers. Different pathways of alternative electron flow coexist in the moss Physcomitrella patens, including cyclic electron flow mediated by the PGRL1/PGR5 complex and pseudo‐cyclic electron flow mediated by the flavodiiron proteins FLV. In this work, we generated P. patens plants carrying both pgrl1 and flva knock‐out mutations. A comparative analysis of the WT, pgrl1, flva, and pgrl1 flva lines suggests that cyclic and pseudo‐cyclic processes have a synergic role in the regulation of photosynthetic electron transport. However, although both contribute to photosystem I protection from overreduction by modulating electron flow following changes in environmental conditions, FLV activity is particularly relevant in the first seconds after a light change whereas PGRL1 has a major role upon sustained strong illumination. Abstract : Photosynthesis is continuously modulated in response to dynamic environmental conditions also through modulation of electron transport. In this work, we applied a multidisciplinary approach to demonstrate the fundamental role of mechanisms for regulation of photosynthetic electron transport in plant response to light dynamics. In their absence, photosynthetic apparatus is damaged with strong negative consequences on growth.