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Guanosine tetraphosphate ( ppGpp ) accumulation inhibits chloroplast gene expression and promotes super grana formation in the moss Physcomitrium ( Physcomitrella ) patens
Author(s) -
Harchouni Seddik,
England Samantha,
Vieu Julien,
Romand Shanna,
Aouane Aicha,
Citerne Sylvie,
Legeret Bertrand,
Alric Jean,
LiBeisson Yonghua,
Menand Benoît,
Field Benjamin
Publication year - 2022
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.18320
Subject(s) - physcomitrella patens , chloroplast , biology , arabidopsis thaliana , microbiology and biotechnology , guanosine , photosynthesis , stringent response , gene , plastid , bryopsida , thylakoid , botany , biochemistry , escherichia coli , mutant
Summary The nucleotides guanosine tetraphosphate and pentaphosphate (or (p)ppGpp) are implicated in the regulation of chloroplast function in plants. (p)ppGpp signalling is best understood in the model vascular plant Arabidopsis thaliana in which it acts to regulate plastid gene expression to influence photosynthesis, plant development and immunity. However, little information is known about the conservation or diversity of (p)ppGpp signalling in other land plants. We studied the function of ppGpp in the moss Physcomitrium (previously Physcomitrella ) patens using an inducible system for triggering ppGpp accumulation. We used this approach to investigate the effects of ppGpp on chloroplast function, photosynthesis and growth. We demonstrate that ppGpp accumulation causes a dramatic drop in photosynthetic capacity by inhibiting chloroplast gene expression. This was accompanied by the unexpected reorganisation of the thylakoid system into super grana. Surprisingly, these changes did not affect gametophore growth, suggesting that bryophytes and vascular plants may have different tolerances to defects in photosynthesis. Our findings point to the existence of both highly conserved and more specific targets of (p)ppGpp signalling in the land plants that may reflect different growth strategies.