Genes Outside the S Supergene Suppress S Functions in Buckwheat (Fagopyrum esculentum)

Abstract

The results suggest that Pennline 10 possesses the s allele as pin does, not an allele produced by the recombination in the S supergene, and that the short style length of Pennline 10 is controlled by multiple genes outside the S supergene.

Homing in on heterostyly

“…Subsequent analysis of the short homostyle did not reveal a simple explanation, but analysis of the long homostyle indicates that the dominant alleles responsible for development of a short style (G) and large pollen grains (P), but not that which determines high anthers (A), have been lost. These data provide evidence of a coadapted linkage group in Turnera, often referred to as a 'supergene', as previously proposed in Fagypyrum and Primula (see for example Richards, 1997 andMatsui et al, 2004).…”

“…In Primula, selffertile and homostyle plants resulting from recombination within the S locus have defined different genetic functions at the Primula S locus responsible for style length (G), anther position (A), pollen size (P) and both pollen (I P ) and style (I S ) incompatibility phenotypes demonstrating the presence of a coadapted linkage group of genes rather than the presence of a single master regulator (Dowrick, 1956;Richards, 1997). The existence of a similar coadapted linkage group has been proposed in F. esculentum (see Matsui et al, 2004 and the references therein).…”

“…Development of the distinct floral morphs with different anther height and style lengths is orchestrated by the S locus (see Richards, 1997). In species such as Turnera subulata (white alder), Fagopyrum esculentum (buckwheat) and Primula vulgaris (primrose), which produce two forms of flower with long and short styles, this phenomenon is also known as distyly and is coordinated by two alleles of the S locus (see for example Matsui et al, 2004;Li et al, 2007;Labonne et al, 2009). In contrast, most self-incompatibility (SI) systems, in which self-pollination is prevented by rejection of pollen following molecular self-recognition, occur in otherwise indistinguishable homomorphic flowers (see for example Hiscock and McInnis, 2003).…”

“…Although mutagenesis has been successfully used in studies of homomorphic SI systems, this is the first published systematic screen in a heterostyled plant aimed at defining the S locus. This study focused on the identification of mutants that affect heteromorphic flower development, whereas previous studies in F. esculentum have focused on the identification of self-fertile mutants (see for example Matsui et al, 2004 and the references therein). In Primula, selffertile and homostyle plants resulting from recombination within the S locus have defined different genetic functions at the Primula S locus responsible for style length (G), anther position (A), pollen size (P) and both pollen (I P ) and style (I S ) incompatibility phenotypes demonstrating the presence of a coadapted linkage group of genes rather than the presence of a single master regulator (Dowrick, 1956;Richards, 1997).…”

Characterization of X-ray-generated floral mutants carrying deletions at the S-locus of distylous Turnera subulata

“…The reduced stigmaanther separation of these five long-styled mutants suggests that gene(s) residing outside the S-locus (on the RP45G6 side) may influence the lengths of styles and stamens. Modifier genes outside of the S-locus have been reported to affect style length in Primula sinensis and Fagopyrum esculentum (Mather, 1950;Matsui et al, 2004Matsui et al, , 2007.…”