Mitochondrial ATP synthase activity affects plastid retrograde signaling
in Arabidopsis
Abstract
Plastid retrograde signaling plays a key role in coordinating the
expression of plastid genes and photosynthesis-associated nuclear genes
( PhANGs). Although plastid retrograde signaling can be
substantially compromised by mitochondrial dysfunction, it is not yet
clear whether specific mitochondrial factors are required to regulate
plastid retrograde signaling. Here, we show that mitochondrial ATP
synthase β-subunit mutants with decreased ATP synthase activity
are impaired in plastid retrograde signaling. Transcriptome analysis
revealed that the expression levels of PhANGs were significantly
higher in seedlings affected in AT5G08670, the gene of the
β-subunit of mitochondrial ATP synthase than in wild-type (WT)
seedlings upon treatment with lincomycin (LIN) and norflurazon (NF).
Further studies showed that the expression of nuclear genes involved in
chloroplast and mitochondrial retrograde signaling was affected in
AT5G08670 mutant seedlings treated with LIN. These changes might
be associated with the repression of some transcriptional factors (TFs),
such as ARF3/ETTIN ( ETT), PLASTID TRANSCRIPTION
FACTOR 1 ( PTF1), CYCLOIDEA AND PCF TRANSCRIPTION FACTOR
2 ( TCP2), and KOW DOMAIN-CONTAINING TRANSCRIPTION FACTOR
1 ( KTF1). These findings indicate that the activity of
mitochondrial ATP synthase affects plastid retrograde signaling.