The Insights into Mitochondrial Genomes of Sunflowers

Abstract

The significant difference in the mtDNA size and structure with simultaneous slow evolving genes makes the mitochondrial genome paradoxical among all three DNA carriers in the plant cell. Such features make mitochondrial genome investigations of particular interest. The genus Helianthus is a diverse taxonomic group, including at least two economically valuable species—common sunflower (H. annuus) and Jerusalem artichoke (H. tuberosus). The successful investigation of the sunflower nuclear genome provided insights into some genomics aspects and significantly intensified sunflower genetic studies. However, the investigations of organelles’ genetic information in Helianthus, especially devoted to mitochondrial genomics, are presented by limited studies. Using NGS sequencing, we assembled the complete mitochondrial genomes for H. occidentalis (281,175 bp) and H. tuberosus (281,287 bp) in the current investigation. Besides the master circle chromosome, in the case of H. tuberosus, the 1361 bp circular plasmid was identified. The mitochondrial gene content was found to be identical for both sunflower species, counting 32 protein-coding genes, 3 rRNA, 23 tRNA genes, and 18 ORFs. The comparative analysis between perennial sunflowers revealed common and polymorphic SSR and SNPs. Comparison of perennial sunflowers with H. annuus allowed us to establish similar rearrangements in mitogenomes, which have possibly been inherited from a common ancestor after the divergence of annual and perennial sunflower species. It is notable that H. occidentalis and H. tuberosus mitogenomes are much more similar to H. strumosus than H. grosseserratus.

Mitogenomic Research of Silverleaf Sunflower (Helianthus argophyllus) and Its Interspecific Hybrids

“…According to the current data, both annual species ( H. annuus , H. argophyllus ) have similar mitochondrial genome organization, differing from those described in the perennial sunflower species ( H. grosseserratus , H. occidentalis , H. strumosus , H. tuberosus ) [ 46 , 47 ]. The most notable difference is that annual species have a long repeat region (about 12.9 kbp), which is absent or significantly reduced in perennial species [ 46 , 47 ]. The non-tandem repeats are important for mitochondrial DNA maintenance since they play a role in recombination [ 51 ].…”

“…In the studied mitogenomes we annotated We then established that the VIR114A × H. argophyllus hybrid mitochondrial DNA was identical to the maternal (VIR114A) line and had only 2 SNP compared with PET1 reference mitogenome (MG735191.1 NCBI accession). Of note, a single nonsynonymous mutation in the atp6 gene (Table S1) was found to be common to the hybrid and its maternal and parental forms, as well as all wild sunflowers whose mitogenomes have been described earlier [46,47] and are available in the NCBI database, including H. grosseserratus (MT588180.1), H. occidentalis (MZ147621.1), H. strumosus (MT588181.1), and H. tuberosus (MZ147622.1). However, this mutation was absent from the available mitogenomic data of sunflower cultivars (SF193, HA89, HA89(PET1), HA412).…”

NGS Reads Dataset of Sunflower Interspecific Hybrids

“…In the case of the H. annuus (VIR117A) × H. strumosus (440679) hybrid, the size of the assembled mitochondrial genome was 305,217 bp; the H. annuus (VIR129A) × H. occidentalis (441062) mitogenome has 281,381 bp counts. Our previous studies investigated the mitochondrial genome structure of parental forms: maternal-H. annuus with PET1 type of cytoplasmic male sterility [10]-and paternal-H. strumosus and H. occidentalis [11,12]. Previous studies allowed us to compare the mitochondrial genome structure of the interspecific hybrid and its parental forms (Figure 1).…”

Sequencing and analysis of the complete mitochondrial genomes of Toona sinensis and Toona ciliata reveal evolutionary features of Toona

“…Mitochondrial DNA (mtDNA) is a genetic material found outside the nucleus that is normally a double-stranded circular molecule with a covalent closure [25][26][27]. Advanced plants have the largest mitochondria of any known higher organism species, ranging from 200 to 2400 kb [28][29][30].…”