A1 Refereed original research article in a scientific journal

In vivo regulation of thylakoid proton motive force in immature leaves




AuthorsHuang W., Suorsa M., Zhang S.

PublisherSpringer Netherlands

Publication year2018

JournalPhotosynthesis Research

Journal name in sourcePhotosynthesis Research

Volume138

Issue2

First page 207

Last page218

Number of pages12

ISSN0166-8595

DOIhttps://doi.org/10.1007/s11120-018-0565-1


Abstract

In chloroplast, proton motive force (pmf) is critical for ATP synthesis and photoprotection. To prevent photoinhibition of photosynthetic apparatus, proton gradient (ΔpH) across the thylakoid membranes needs to be built up to minimize the production of reactive oxygen species (ROS) in thylakoid membranes. However, the regulation of thylakoid pmf in immature leaves is little known. In this study, we compared photosynthetic electron sinks, P700 redox state, non-photochemical quenching (NPQ), and electrochromic shift (ECS) signal in immature and mature leaves of a cultivar of Camellia. The immature leaves displayed lower linear electron flow and cyclic electron flow, but higher levels of NPQ and P700 oxidation ratio under high light. Meanwhile, we found that pmf and ΔpH were higher in the immature leaves. Furthermore, the immature leaves showed significantly lower thylakoid proton conductivity than mature leaves. These results strongly indicated that immature leaves can build up enough ΔpH by modulating proton efflux from the lumenal side to the stromal side of thylakoid membranes, which is essential to prevent photoinhibition via thermal energy dissipation and photosynthetic control of electron transfer. This study highlights that the activity of chloroplast ATP synthase is a key safety valve for photoprotection in immature leaves.



Last updated on 2024-26-11 at 11:54