The wild grape genome sequence provides insights into the transition from dioecy to hermaphroditism during grape domestication
Abstract
Background: A key step in domestication of the grapevine was the transition from
separate sexes (dioecy) in wild Vitis vinifera ssp. sylvestris (V. sylvestris) to hermaphroditismin
cultivated Vitis vinifera ssp. sativa (V. vinifera). It is known that V. sylvestris has an XY system
and V. vinifera a modified Y haplotype (Yh) and that the sex locus is small, but it has not
previously been precisely characterized.
Results: We generate a high-quality de novo reference genome for V. sylvestris, onto which
we map whole-genome re-sequencing data of a cross to locate the sex locus. Assembly of
the full X, Y, and Yh haplotypes of V. sylvestris and V. vinifera sex locus and examining their
gene content and expression profiles during flower development in wild and cultivated
accessions show that truncation and deletion of tapetum and pollen development genes
on the X haplotype likely causes male sterility, while the upregulation of a Y allele of a
cytokinin regulator (APRT3) may cause female sterility. The downregulation of this cytokinin
regulator in the Yh haplotype may be sufficient to trigger reversal to hermaphroditism.
Molecular dating of X and Y haplotypes is consistent with the sex locus being as old as the
Vitis genus, but the mechanism by which recombination was suppressed remains
undetermined.
Conclusions: We describe the genomic and evolutionary characterization of the sex locus
of cultivated and wild grapevine, providing a coherent model of sex determination in the
latter and for transition from dioecy to hermaphroditism during domestication.
Domains
Life Sciences [q-bio]
Origin : Publisher files allowed on an open archive
Loading...
