A breakdown of Brassica self-incompatibility in ARC1 antisense transgenic plants

Self-incompatibility, the rejection of self pollen, is the most widespread mechanism by which flowering plants prevent inbreeding. In Brassica, the S receptor kinase (SRK) has been implicated in the self-incompatibility respo nse, but the molecular mechanisms involving SRK are unknown. One putative d ownstream effector for SRK is ARC1, a protein that binds to the SRK kinase domain. Here it is shown that suppression of ARC1 messenger RNA levels in t he self-incompatible Brassica napus W1 line is correlated with a partial br eakdown of self-incompatibility, resulting in seed production. This provide s strong evidence that ARC1 is a positive effector of the Brassica self-inc ompatibility response.