A Nuclear restorer-of-fertility Mutation Disrupts Accumulation of Mitochondrial ATP Synthase Subunit in Developing Pollen of S Male-Sterile Maize

Corresponding author: Christine D. Chase, 1301 Fifield Hall, University of Florida, Gainesville, FL 32611., ctdc{at}mail.ifas.ufl.edu (E-mail)

Communicating editor: J. BIRCHLER

Mitochondrial biogenesis and function depend upon the interaction of mitochondrial and nuclear genomes. Forward genetic analysis of mitochondrial function presents a challenge in organisms that are obligated to respire. In the S-cytoplasmic male sterility (CMS-S) system of maize, expression of mitochondrial open reading frames (orf355-orf77) conditions collapse of developing haploid pollen. Nuclear restorer-of-fertility mutations that circumvent pollen collapse are often homozygous lethal. These spontaneous mutations potentially result from disruption of nuclear genes required for mitochondrial gene expression, in contrast to homozygous-viable restorer-of-fertility alleles that function to block or compensate for the expression of mitochondrial CMS genes. Consistent with this hypothesis, the homozygous-lethal restoring allele historically designated RfIII was shown to be recessive in diploid pollen produced by tetraploid CMS-S plants. Accordingly, the symbol for this allele has been changed to restorer-of-fertility lethal 1 (rfl1). In haploid rfl1 pollen, orf355-orf77 transcripts and mitochondrial transcripts encoding the -subunit of the ATP synthase (ATPA) were decreased in abundance. Haploid rfl1 pollen failed to accumulate wild-type levels of ATPA protein, indicating that functional requirements for mitochondrial protein accumulation are relaxed in maize pollen. The CMS-S system and rfl mutations therefore allow for the selection of nuclear mutations disrupting mitochondrial biogenesis in a multicellular eukaryote.

This article has been cited by other articles:

				S. Fujii and K. Toriyama Genome Barriers between Nuclei and Mitochondria Exemplified by Cytoplasmic Male Sterility Plant Cell Physiol., October 1, 2008; 49(10): 1484 - 1494. [Abstract] [Full Text] [PDF]

				H. V. Tang, J. F. Pedersen, C. D. Chase, and D. R. Pring Fertility Restoration of the Sorghum A3 Male-Sterile Cytoplasm through a Sporophytic Mechanism Derived from Sudangrass Crop Sci., May 31, 2007; 47(3): 943 - 950. [Abstract] [Full Text] [PDF]

				M. D. Howell, N. Fahlgren, E. J. Chapman, J. S. Cumbie, C. M. Sullivan, S. A. Givan, K. D. Kasschau, and J. C. Carrington Genome-Wide Analysis of the RNA-DEPENDENT RNA POLYMERASE6/DICER-LIKE4 Pathway in Arabidopsis Reveals Dependency on miRNA- and tasiRNA-Directed Targeting PLANT CELL, March 1, 2007; 19(3): 926 - 942. [Abstract] [Full Text] [PDF]

				Z. Wang, Y. Zou, X. Li, Q. Zhang, L. Chen, H. Wu, D. Su, Y. Chen, J. Guo, D. Luo, et al. Cytoplasmic Male Sterility of Rice with Boro II Cytoplasm Is Caused by a Cytotoxic Peptide and Is Restored by Two Related PPR Motif Genes via Distinct Modes of mRNA Silencing PLANT CELL, March 1, 2006; 18(3): 676 - 687. [Abstract] [Full Text] [PDF]

				M. R. Hanson and S. Bentolila Interactions of Mitochondrial and Nuclear Genes That Affect Male Gametophyte Development PLANT CELL, June 1, 2004; 16(suppl_1): S154 - S169. [Full Text] [PDF]

				S. Gabay-Laughnan, C. D. Chase, V. M. Ortega, and L. Zhao Molecular-Genetic Characterization of CMS-S Restorer-of-Fertility Alleles Identified in Mexican Maize and Teosinte Genetics, February 1, 2004; 166(2): 959 - 970. [Abstract] [Full Text] [PDF]