|Melgar, Sergio - UW MADISON|
Submitted to: National Allium Research Conference
Publication Type: Abstract Only
Publication Acceptance Date: November 13, 2008
Publication Date: December 15, 2008
Citation: Melgar, S., Havey, M.J. 2008. Genomic and proteomic analyses of male-fertility restoration in onion [abstract]. National Allium Research Conference. p. 20. Technical Abstract: Production of hybrid-onion seed is dependent on cytoplasmic-genic male sterility (CMS). The most commonly used CMS in onion requires the presence of male-sterile (S) cytoplasm and recessive alleles at one nuclear male-fertility restoration (Ms) locus. Molecular markers have been developed that distinguish S and normal (N) male-fertile cytoplasms and a single nucleotide polymorphism (AOB272) has been identified tightly linked to the Ms locus. We are using candidate gene and proteomic approaches in order to clone Ms and develop a marker that can be scored without regard to recombination. Nuclear restorers cloned from other plants often carry pentatricopeptide repeats (PPRs), which are 35 degenerated amino-acid motifs tandemly arranged in proteins. We evaluated expressed and genomic sequences of onion and identified over 40 different PPR genes, none of which showed linkage to Ms. Proteomic analyses are being carried out using mitochondrial proteins isolated from male-sterile (S msms) and male-fertility-restored (S Msms) plants. 2D gels revealed relatively few differences and partial-protein sequences were generated by mass spectrometry. Peptide sequences are being searched against the DNA databases to identify differentially expressed genes, and polymorphisms are being mapped to assess linkage to Ms.