Present address: Promega Corporation, 5445 E. Cheryl Parkway, Madison, WI 53711, USA.
FtsHi1/ARC1 is an essential gene in Arabidopsis that links chloroplast biogenesis and division
Article first published online: 12 OCT 2012
© 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd
The Plant Journal
Volume 72, Issue 5, pages 856–867, December 2012
How to Cite
Kadirjan-Kalbach, D. K., Yoder, D. W., Ruckle, M. E., Larkin, R. M. and Osteryoung, K. W. (2012), FtsHi1/ARC1 is an essential gene in Arabidopsis that links chloroplast biogenesis and division. The Plant Journal, 72: 856–867. doi: 10.1111/tpj.12001
- Issue published online: 22 NOV 2012
- Article first published online: 12 OCT 2012
- Accepted manuscript online: 18 AUG 2012 06:12AM EST
- Received 26 June 2012; revised 9 August 2012; accepted 15 August 2012; published online 12 October 2012.
- FtsHi ;
- plastid division;
- chloroplast biogenesis;
- plastid development;
- Arabidopsis thaliana
The Arabidopsis arc1 (accumulation and replication of chloroplasts 1) mutant has pale seedlings and smaller, more numerous chloroplasts than the wild type. Previous work has suggested that arc1 affects the timing of chloroplast division but does not function directly in the division process. We isolated ARC1 by map-based cloning and discovered it encodes FtsHi1 (At4g23940), one of several FtsHi proteins in Arabidopsis. These poorly studied proteins resemble FtsH metalloproteases important for organelle biogenesis and protein quality control but are presumed to be proteolytically inactive. FtsHi1 bears a predicted chloroplast transit peptide and localizes to the chloroplast envelope membrane. Phenotypic studies showed that arc1 (hereafter ftsHi1-1), which bears a missense mutation, is a weak allele of FtsHi1 that disrupts thylakoid development and reduces de-etiolation efficiency in seedlings, suggesting that FtsHi1 is important for chloroplast biogenesis. Consistent with this finding, transgenic plants suppressed for accumulation of an FtsHi1 fusion protein were often variegated. A strong T-DNA insertion allele, ftsHi1-2, caused embryo-lethality, indicating that FtsHi1 is an essential gene product. A wild-type FtsHi1 transgene rescued both the chloroplast division and pale phenotypes of ftsHi1-1 and the embryo-lethal phenotype of ftsHi1-2. FtsHi1 overexpression produced a subtle increase in chloroplast size and decrease in chloroplast number in wild-type plants while suppression led to increased numbers of small chloroplasts, providing new evidence that FtsHi1 negatively influences chloroplast division. Taken together, our analyses reveal that FtsHi1 functions in an essential, envelope-associated process that may couple plastid development with division.