Molecular-Genetic Characterization of CMS-S Restorer-of-Fertility Alleles Identified in Mexican Maize and Teosinte

Corresponding author: Susan Gabay-Laughnan, 265 Morrill Hall, University of Illinois, 505 S. Goodwin Ave., Urbana, IL 61801., gabaylau{at}life.uiuc.edu (E-mail)

Communicating editor: J. A. BIRCHLER

Restorer-of-fertility (Rf) alleles for S-type cytoplasmic male sterility (CMS-S) are prevalent in Mexican races of maize and teosinte. Forty-five Rf alleles from 26 races of maize and 6 Rf alleles from different accessions of teosinte were found to be homozygous viable, consistent with the hypothesis that they are naturally occurring Rf alleles. Mapping and allelism studies were performed to assess the number of genes represented by these 51 alleles. Forty-two of the Rf alleles mapped to the long arm of chromosome 2 (2L), and 5 of these were further mapped to the whp1-rf3 region. The Rf3 restoring allele, found in some U.S. maize inbred lines, cosegregates with internal processing of CMS-S mitochondrial transcripts. Three of the 5 mapped Rf alleles were associated with a similar RNA processing event. Allelism or tight linkage was confirmed between Rf3 and 2 teosinte alleles (Rf K-69-6 and Rf 9477) and between Rf3 and the Cónico Norteño allele Rf C-N (GTO 22). The rf3 region of 2L potentially encodes a complex of linked rf genes. The prevalence of restoring alleles in this chromosomal region, among normal-cytoplasm accessions of Mexican maize and teosinte, supports the conclusion that these alleles have functions in normal mitochondrial gene expression that by chance allow them to restore male fertility in S cytoplasm.

This article has been cited by other articles:

				S. Gabay-Laughnan, E. V. Kuzmin, J. Monroe, L. Roark, and K. J. Newton Characterization of a Novel Thermosensitive Restorer of Fertility for Cytoplasmic Male Sterility in Maize Genetics, May 1, 2009; 182(1): 91 - 103. [Abstract] [Full Text] [PDF]

				C. Weider, P. Stamp, N. Christov, A. Husken, X. Foueillassar, K.-H. Camp, and M. Munsch Stability of Cytoplasmic Male Sterility in Maize under Different Environmental Conditions Crop Sci., January 28, 2009; 49(1): 77 - 84. [Abstract] [Full Text] [PDF]