"ABI3 (ABscisic acid Insensitive 3), a transcription factor of the ABA signal transduction pathway, plays a major role during seed development, dormancy inception and dormancy maintenance. This protein appears to also function in meristematic and vegetative plant tissues, and under certain stress conditions. We have isolated the ABI3 gene ortholog (CnABI3) from yellow-cedar and found that it was functionally similar to other ABI3 genes of angiosperms. Here we report that using a yeast two-hybrid approach, we have identified another protein of yellow-cedar (CnAIP2) that physically interacts with CnABI3. Functional analyses revealed that CnAIP2 plays important roles during key transitions in the plant lifecycle: (1) CnAIP2 impaired seed development and reduced seed dormancy; (2) CnAIP2 promoted root development, particularly the initiation of lateral roots, and the CnAIP2 gene promoter was exquisitely auxin-sensitive. (3) CnAIP2 promoted the transition from vegetative growth to reproductive initiation, i.e. flowering. The nature of the effects of CnAIP2 on these processes and other evidence places CnAIP2 in the category of a 'global' regulator, whose actions are antagonistic to those of ABI3."