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Nitric Oxide Remodels the Photosynthetic Apparatus upon S-Starvation in Chlamydomonas reinhardtii

TitleNitric Oxide Remodels the Photosynthetic Apparatus upon S-Starvation in Chlamydomonas reinhardtii
Publication TypeJournal Article
Year of Publication2019
AuthorsDe Mia, M, Lemaire, SD, Choquet, Y, Wollman, FA
JournalPlant Physiol
Volume179
Pagination718-731
Date PublishedFeb
ISBN Number1532-2548 (Electronic)0032-0889 (Linking)
KeywordsChlamydomonas reinhardtii/drug effects/*physiology, Chloroplast Proteins/metabolism, Cytochrome b6f Complex/metabolism, Light, Nitric Oxide Donors/pharmacology, Nitric Oxide/*metabolism, Peptide Hydrolases/metabolism, Photosynthesis/*physiology, Plant Proteins/metabolism, Ribulose-Bisphosphate Carboxylase/metabolism, Signal Transduction, Sulfur/*metabolism
Abstract

Many photosynthetic autotrophs have evolved responses that adjust their metabolism to limitations in nutrient availability. Here we report a detailed characterization of the remodeling of photosynthesis upon sulfur starvation under heterotrophy and photo-autotrophy in the green alga (Chlamydomonas reinhardtii). Photosynthetic inactivation under low light and darkness is achieved through specific degradation of Rubisco and cytochrome b 6 f and occurs only in the presence of reduced carbon in the medium. The process is likely regulated by nitric oxide (NO), which is produced 24 h after the onset of starvation, as detected with NO-sensitive fluorescence probes visualized by fluorescence microscopy. We provide pharmacological evidence that intracellular NO levels govern this degradation pathway: the addition of a NO scavenger decreases the rate of cytochrome b 6 f and Rubisco degradation, whereas NO donors accelerate the degradation. Based on our analysis of the relative contribution of the different NO synthesis pathways, we conclude that the NO2-dependent nitrate reductase-independent pathway is crucial for NO production under sulfur starvation. Our data argue for an active role for NO in the remodeling of thylakoid protein complexes upon sulfur starvation.

URLhttp://www.ncbi.nlm.nih.gov/pubmed/30530737
Short TitlePlant physiology