Allelic diversity of Ferritin III and PMT IV genes related to iron chlorosis in some citrus rootstoc

Iron (Fe) is one of the most important elements in plant mineral nutrition. Fe deficiency is critical abioticstress factor for Mediterranean citriculture and the development of marker assisted selection (MAS) for thistrait would be a great aid for rootstock breeding. In this study DNA sequencing and SSCP (Single StrandedConformation Polymorphism) analysis were performed to discover allelic diversity of genes related to ironchlorosis tolerance in citrus. Two iron chlorosis tolerance candidate genes were selected from existing CitrusESTs databases and Arabidopsis thaliana genome databases. Ferritin-3 chloroplast precursor and putativemembrane transporter candidate gene sequences were used to define primers in conserved regions. Sixcitrus genotypes from the basic taxon of Citrus where used to identify polymorphic areas in the genes. Directsequencing of amplified DNA fragments of candidate genes was performed and SNPs (single-nucleotidepolymorphisms) and InDels (Insertions/Deletions) where searched after sequence alignment. A total of 6840bp DNA fragments were sequenced and 263 SNPs and 15 InDels were determined. New primers were defined,in conserved areas flanking polymorphic ones, for Single Strand Conformation Polymorphism (SSCP) analysis. SSCP-PCR analysis was performed with twenty-five Citrus genotypes. The neighbor joining method was usedfor cluster analysis. Phylogenetic origin of the alleles and genetic relationships of genotypes were discussed.