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Origin of CMS-PET1 cytotype in cultivated sunflower: a new insight
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  • Kirill Azarin,
  • Alexander Usatov,
  • Alexandra Kasyanova,
  • Maksim Makarenko,
  • Vera Gavrilova
Kirill Azarin
Southern Federal University

Corresponding Author:[email protected]

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Alexander Usatov
Southern Federal University
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Alexandra Kasyanova
Southern Federal University
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Maksim Makarenko
Kharkevich Institute for Information Transmission Problems RAS
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Vera Gavrilova
N I Vavilov Institute of Plant Genetic Resources
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Abstract

The vast majority of commercial sunflower hybrids worldwide are produced using cytoplasmic male sterility (CMS) of the PET1 type, resulting from the interspecific hybridization of Helianthus petiolaris with Helianthus annuus. In this study, the open reading frame, orfH522, associated with the CMS-PET1 phenotype, was revealed for the first time in the 3’-flanking region of the mitochondrial atpA gene in wild H. annuus. An analysis of whole genome data from 1089 accessions showed that the frequency of occurrence of CMS-orfH522 in wild H. annuus populations is 3.58%, while in wild H. petiolaris populations, it is 1.26%. The presence of additional genomic data with insufficient coverage of the orfH522 sequence indicates that the potential frequency of occurrence of CMS-orfH522 in natural sunflower populations may be two times higher. Based on these results and previous studies, PET1-CMS was suggested to be a natural cytotype of H. annuus, and the appearance of the CMS phenotype in cultivated sunflowers is associated with the loss of stabilizing nuclear genes of fertility restorers, which occurred during interspecific hybridization. These data may explain the patterns of differential cytoplasmic and nuclear introgression occurring in wild sunflower and are useful for further evolutionary studies.