Characterization of the mitochondrial genome of the MAX1 type of cytoplasmic male-sterile sunflower.

ABSTRACT: BACKGROUND:More than 70 cytoplasmic male sterility (CMS) types have been identified in Helianthus, but only for less than half of them, research of mitochondrial organization has been conducted. Moreover, complete mitochondrion sequences have only been published for two CMS sources - PET1 and PET2. It has been demonstrated that other sunflower CMS sources like MAX1, significantly differ from the PET1 and PET2 types. However, possible molecular causes for the CMS induction by MAX1 have not yet been proposed. In the present study, we have investigated structural changes in the mitochondrial genome of HA89 (MAX1) CMS sunflower line in comparison to the fertile mitochondrial genome. RESULTS:Eight significant major reorganization events have been determined in HA89 (MAX1) mtDNA: one 110?kb inverted region, four deletions of 439?bp, 978?bp, 3183?bp and 14,296?bp, respectively, and three insertions of 1999?bp, 5272?bp and 6583?bp. The rearrangements have led to functional changes in the mitochondrial genome of HA89 (MAX1) resulting in the complete elimination of orf777 and the appearance of new ORFs - orf306, orf480, orf645 and orf1287. Aligning the mtDNA of the CMS sources PET1 and PET2 with MAX1 we found some common reorganization features in their mitochondrial genome sequences. CONCLUSION:The new open reading frame orf1287, representing a chimeric atp6 gene, may play a key role in MAX1 CMS phenotype formation in sunflower, while the contribution of other mitochondrial reorganizations seems to appear negligible for the CMS development.

SUBMITTER: Makarenko MS 

PROVIDER: S-EPMC6394147 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature