Abstract

Commercial sunflower production depends on development and use of CMS-based hybrids with heterosis effect. The discovery of nuclear Rf-genes, capable to suppress CMS pheno type, made possible the using CMS-Rf genetic systems as a base for practical use of heterosis effect for different crops. Rf1 gene is the most common used fertility restorer gene for development of sunflower hybrids with a hybrid vigor. New data about Rf1 gene localization in sunflower genome were found in the last few years. However, the ambiguity of precise Rf1 gene localization requires additional efforts for study of structure and diversity of the Rf1 candidate loci across sunflower accessions. That is why this study was conducted during the 2020 at Moscow State University, Moscow region, Russia, to analyze the distribution of Rf1 candidate genes in sunflower lines with different genotypes based on DNA markers. All the 25 candidate genes identified in previous research were included into analysis. Based on genome HanXRQr1.0 annotation, nucleotide sequences of candidate genes were extracted and used for development of gene-specific primer pairs. PCR analysis was performed with those primers and DNA samples isolated from twelve sunflower restorer lines carrying dominant allele of the Rf1 gene and 12 sterility maintainer lines with the recessive allele and results were visualized by gel electrophoresis. The significant variability of the locus, located in chromosome 13 in the genome sequence from position 169,655,088 to 178217103, was detected. Multiple cases of lack of gene-specific PCR-products and presence of an additional fragments at electrophoretic spectra of sunflower lines could be the result of loss and duplication of analyzed genes sequences. Totally 14 different haplotypes were revealed in the study among them 8 were in sterility maintainer lines and 6 in fertility restorer lines. The structure of Rf1 candidate locus was analyzed on restorer and sterility maintainer lines of sunflower in this study. This work will be useful for further studying of structure, evolution and identification of sunflower Rf1 gene.