Mechanisms of self-incompatibility in grasses (Review)

In grasses, self-incompatibilty (SI) is based on two loci, S and Z, but the mechanisms are much less well understood relative to other gametophytic SI systems. Klass et al. review recent progress towards elucidating grass SI, and by identifying Ca binding and kinase domains from subtracted Lolium stigma cDNA libraries they strengthen the case for involvement of calcium signalling and phosphorylation in the process. This is supported by the inhibition of Lolium SI by Ca²⁺ channel blockers, and by findings of increased phosphorylation activity during SI responses.