Open AccessChloroplast biogenesis: The use of mutants to study the etioplast–chloroplast transition
Author(s) -
Katrin Philippar,
Tina Geis,
Iryna Ilkavets,
Ulrike Oster,
Serena Schwenkert,
Jörg Meurer,
Jürgen Soll
Publication year - 2007
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.0610062104
Subject(s) - protochlorophyllide , chloroplast , biogenesis , mutant , biology , biochemistry , chloroplast membrane , microbiology and biotechnology , gene , thylakoid
In angiosperm plants, the etioplast–chloroplast transition is light-dependent. A key factor in this process is the protochlorophyllide oxidoreductase A (PORA), which catalyzes the light-induced reduction of protochlorophyllide to chlorophyllide. The import pathway of the precursor protein prePORA into chloroplasts was analyzedin vivo andin vitro by using homozygous loss-of-function mutants in genes coding for chlorophyllidea oxygenase (CAO) or for members of the outer-envelope solute-channel protein family of 16 kDa (OEP16), both of which have been implied to be key factors for the import of prePORA. Ourin vivo analyses show thatcao oroep16 mutants contain a normally structured prolamellar body that contains the protochlorophyllide holochrome. Furthermore, etioplasts fromcao andoep16 mutants contain PORA protein as found by mass spectrometry. Our data demonstrate that both CAO and OEP16 are dispensable for chloroplast biogenesis and play no central role in the import of prePORAin vivo andin vitro as further indicated by protein import studies.