Abstract:The entire chloroplast and mitochondrial genomes of domesticated and wild type sunflower were sequenced. The comparative analysis of chloroplast genomes revealed 43 variant sites, including 21 polymorphic SSR loci and 22 SNPs. About 14 variant sites were found by collation of mitochondrial DNA (mtDNA), among them 4 SSRs, 8 SNPs and 2 deletions. About 9 SNPs were located in coding region of chloroplast DNA (cpDNA) and single SNP was mapped in mitochondrial gene. Only three SNPs caused amino acid changes: Two SNPs in cpDNA and one mtDNA SNP. Despite the fact that sunflower mitochondrial genome sequence is twice as long as chloroplast genome sequence, mtDNA has one third as much variant sites than cpDNA.
BackgroundCytoplasmic male sterility (CMS) is a common phenotype in higher plants, that is often associated with rearrangements in mitochondrial DNA (mtDNA), and is widely used to produce hybrid seeds in a variety of valuable crop species. Investigation of the CMS phenomenon promotes understanding of fundamental issues of nuclear-cytoplasmic interactions in the ontogeny of higher plants. In the present study, we analyzed the structural changes in mitochondrial genomes of three alloplasmic lines of sunflower (Helianthus annuus L.). The investigation was focused on CMS line PET2, as there are very few reports about its mtDNA organization.MethodsThe NGS sequencing, de novo assembly, and annotation of sunflower mitochondrial genomes were performed. The comparative analysis of mtDNA of HA89 fertile line and two HA89 CMS lines (PET1, PET2) occurred.ResultsThe mtDNA of the HA89 fertile line was almost identical to the HA412 line (). The comparative analysis of HA89 fertile and CMS (PET1) analog mitochondrial genomes revealed 11,852 bp inversion, 4,732 bp insertion, 451 bp deletion and 18 variant sites. In the mtDNA of HA89 (PET2) CMS line we determined 27.5 kb and 106.5 kb translocations, 711 bp and 3,780 bp deletions, as well as, 5,050 bp and 15,885 bp insertions. There are also 83 polymorphic sites in the PET2 mitochondrial genome, as compared with the fertile line.DiscussionThe observed mitochondrial reorganizations in PET1 resulted in only one new open reading frame formation (orfH522), and PET2 mtDNA rearrangements led to the elimination of orf777, duplication of atp6 gene and appearance of four new ORFs with transcription activity specific for the HA89 (PET2) CMS line—orf645, orf2565, orf228 and orf285. Orf228 and orf285 are the atp9 chimeric ORFs, containing transmembrane domains and possibly may impact on mitochondrial membrane potential. So orf228 and orf285 may be the cause for the appearance of the PET2 CMS phenotype, while the contribution of other mtDNA reorganizations in CMS formation is negligible.
One of the areas of biotechnology sunflower is the development and testing of DNA markers of important agronomic traits and in particular markers of resistance to downy mildew. Resistance of 16 Rf-lines of sunflower to the races 330 and 710 of Plasmopara halstedii has been studied. Genotyping of these lines was carried out using 9 STS-markers of three Pl-loci, Pl 5 , Pl 6 and Pl 8 , associated with the resistance of sunflower to downy mildew. Only two out of nine STS-markers, НаР2 and НаР3 (locus Pl 6), allowed us to identify the lines, which demonstrated resistance to the downy mildew under the conditions of artificial infection.
Markin N., Usatov A., Makarenko M., Azarin K., Gorbachenko O., Kolokolova N., Usatenko T., Markina O., Gavrilova V. (2017): Study of informative DNA markers of the Rf1 gene in sunflower for breeding practice. Czech J. Genet. Plant Breed., 53: 69−75.The investigation of DNA markers associated with the pollen fertility restoration gene (Rf1) was conducted in Helianthus. Two sequence-characterized amplified region (SCAR) markers -HRG01 and HRG02 were informative for the identification of Rf1 gene in selections of sunflower plants. The codominant character of the HRG01 marker and HRG01 amplicon polymorphism has been determined. Five annual and twenty-six perennial species of sunflower were tested for the presence of Rf genotypes. HRG02 proved to be a more appropriate marker for Rf1 determination in perennial species, and HRG01 was more informative for annual species. We have also developed the multiplex RT-PCR test system, which allows simultaneously detecting the dominant allele of Rf1 and CMS-PET1 associated mitotype.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.