A cryptic modifier causing transient self-incompatibility in Arabidopsis thaliana

Curr Biol. 2007 Apr 17;17(8):734-40. doi: 10.1016/j.cub.2007.03.022. Epub 2007 Apr 5.


Breakdown of the pollination barrier of self-incompatibility (SI) in older flowers, a phenomenon known as pseudo-self-compatibility or transient SI, has been described as an advantageous reproductive assurance strategy that allows selfing after opportunities for out-crossing have been exhausted [1-9]. Pseudo-self-compatibility is quite prevalent as a mixed mating strategy in nature, but the underlying molecular mechanisms are not known. We had previously shown that Arabidopsis thaliana exhibits cryptic natural variation for pseudo-self-compatibility, which is uncovered by transformation of different accessions with SI specificity-determining SRK and SCR genes from its self-incompatible sister species A. lyrata[10, 11]. Here, by using this transgenic A. thaliana model, we show that pseudo-self-compatibility is caused by a hypomorphic allele of PUB8, an S-locus-linked gene encoding a previously uncharacterized ARM repeat- and U box-containing protein that regulates SRK transcript levels. This is the first gene underlying pseudo-self-compatibility to be identified and the first report in which cryptic natural variation unveiled by a transgene enabled the cloning of a gene for a complex trait.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Arabidopsis / physiology*
  • Arabidopsis Proteins / physiology*
  • Base Sequence
  • Crosses, Genetic
  • Flowers / physiology
  • Molecular Sequence Data
  • Plants, Genetically Modified / physiology


  • Arabidopsis Proteins