Hormone-mediated inflorescence patterning in barley ($)

barleyinflorescenceYoussef et al. investigate how the vsr2 mutant affects inflorescence (spike) development in barley. In the two-row variety, at each node there are two sterile spikelets and a single grain forms. In the six-row variety, each of the spikelets is fertile and three grains form at each node. The vsr2 mutation partially converts the two-row form into a six-row form, predominately at the base of the spike. This effect was correlated with higher levels of sucrose and cytokinin and lower auxin levels, and accompanying changes in hormone biosynthesis genes. The Vsr2 locus was found to encode a SHI-type transcription factor, similar to genes shown previously to affect floral development and auxin biosynthesis. Nat. Genet. 10.1038/ng.3717