Ectopic expression of wheat and barley DOG1-like genes promotes seed dormancy in Arabidopsis.

To develop strategies for manipulating the level of crop seed dormancy, it is necessary to search for the genes that control dormancy. In this study, we investigated whether wheat and barley homologues of the Arabidopsis dormancy gene DOG1 (Delay of Germination 1), TaDOG1L1 and HvDOG1L1 (respectively), also induce seed dormancy. Because their sequence similarity to DOG1 is low and the tissue-specific expression pattern of DOG1 was not conserved in either of these genes, these genes do not appear to retain the function of DOG1. However, ectopic overexpression of either of these DOG1 homologues in transgenic Arabidopsis markedly increased seed dormancy. Furthermore, dormancy release during dry seed storage in the transgenic Arabidopsis overexpressing the Triticeae genes occurred similarly to that in a transgenic line overexpressing DOG1. This evidence demonstrates conservation of the function of DOG1 in both TaDOG1L1 and HvDOG1L1. Thus, these DOG1-like genes in wheat and barley are good candidate transgenes for reducing pre-harvest germination in wheat.