Open AccessPlastoglobular protein 18 is involved in chloroplast function and thylakoid formation
Author(s) -
Roberto EspinozaCorral,
Steffen Heinz,
Andreas Klingl,
Peter Jahns,
Martin Lehmann,
Jörg Meurer,
Jörg Nickelsen,
Jürgen Soll,
Serena Schwenkert
Publication year - 2019
Publication title -
journal of experimental botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.616
H-Index - 242
eISSN - 1460-2431
pISSN - 0022-0957
DOI - 10.1093/jxb/erz177
Subject(s) - thylakoid , chloroplast , plastid , synechocystis , biology , arabidopsis , photosynthesis , cyanobacteria , xanthophyll , mutant , arabidopsis thaliana , chlorophyll , biochemistry , microbiology and biotechnology , botany , biophysics , genetics , gene , bacteria
Plastoglobules are lipoprotein particles that are found in different types of plastids. They contain a very specific and specialized set of lipids and proteins. Plastoglobules are highly dynamic in size and shape, and are therefore thought to participate in adaptation processes during either abiotic or biotic stresses or transitions between developmental stages. They are suggested to function in thylakoid biogenesis, isoprenoid metabolism, and chlorophyll degradation. While several plastoglobular proteins contain identifiable domains, others provide no structural clues to their function. In this study, we investigate the role of plastoglobular protein 18 (PG18), which is conserved from cyanobacteria to higher plants. Analysis of a PG18 loss-of-function mutant in Arabidopsis thaliana demonstrated that PG18 plays an important role in thylakoid formation; the loss of PG18 results in impaired accumulation, assembly, and function of thylakoid membrane complexes. Interestingly, the mutant accumulated less chlorophyll and carotenoids, whereas xanthophyll cycle pigments were increased. Accumulation of photosynthetic complexes is similarly affected in both a Synechocystis and an Arabidopsis PG18 mutant. However, the ultrastructure of cyanobacterial thylakoids is not compromised by the lack of PG18, probably due to its less complex architecture.