Format

Send to

Choose Destination
Plant Physiol. 2019 Feb 13. pii: pp.00070.2019. doi: 10.1104/pp.19.00070. [Epub ahead of print]

Extrachloroplastic PP7L Functions in Chloroplast Development and Abiotic Stress Tolerance.

Author information

1
Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-Universität München CITY: Planegg-Martinsried Germany [DE].
2
Plant Development, Department Biology I, Ludwig-Maximilians-Universität München CITY: Planegg-Martinsried Germany [DE].
3
Institute of Biology II, Faculty of Biology, University of Freiburg CITY: Freiburg Germany [DE].
4
CRAG CITY: Bellaterra- Cerdanyola del Valles POSTAL_CODE: 08193 Spain [ES].
5
Francis Crick Institute CITY: London United Kingdom [GB].
6
Faculty of Biology CITY: Freiburg POSTAL_CODE: 79104 Germany [DE].
7
University of Munich CITY: Muenchen POSTAL_CODE: D-82152 Germany [DE].
8
Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-Universität München CITY: Planegg-Martinsried POSTAL_CODE: 82152 Germany [DE] tatjana.kleine@lrz.uni-muenchen.de.

Abstract

Chloroplast biogenesis is indispensable for proper plant development and environmental acclimation. In a screen for mutants affected in photosynthesis, we identified the pp7l mutant, which displayed delayed chloroplast development in cotyledons and young leaves. PP7L, PP7 and PP7-long constitute a subfamily of phosphoprotein phosphatases (PPPs). PP7 is thought to transduce a blue-light signal perceived by cryptochromes and phytochrome A that induces expression of SIGMA FACTOR 5 (SIG5). We observed that, like PP7, PP7L was predominantly localized to the nucleus in Arabidopsis thaliana, and the pp7l phenotype was similar to that of the sig6 mutant. However, SIG6 expression was unaltered in pp7l mutants. Instead, loss of PP7L compromised translation and ribosomal RNA maturation in chloroplasts, pointing to a distinct mechanism influencing chloroplast development. Promoters of genes deregulated in pp7l-1 were enriched in PIF-binding motifs and the transcriptome of pp7l-1 resembled those of pif and csn mutants. However, pif and csn mutants, as well as cop1, cry1 cry2 and phyA phyB mutants, do not share the pp7l photosynthesis phenotype. PhyB protein levels were elevated in pp7l mutants, but phytochrome B overexpression plants did not resemble pp7l. These results indicate that PP7L operates through a different pathway and that the control of greening and photosystem biogenesis can be separated. The lack of PP7L increased susceptibility to salt and high-light stress, whereas PP7L overexpression conferred resistance to high-light stress. Strikingly, PP7L was specifically recruited to Brassicales for the regulation of chloroplast development. This study adds another player involved in chloroplast biogenesis.

PMID:
30760637
DOI:
10.1104/pp.19.00070
Free full text

Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center