Floral initiation process at the soybean shoot apical meristem may involve multiple hormonal pathways.

Flowering and seed set underpin most of the agriculture production. In the 57 Issue of The Plant Journal, we analysed the gene expression changes in the shoot apical meristem (SAM) during the transition from vegetative to flowering phase in soybean, an important legume crop. We identified a number of genes that are actively transcribed or repressed during the transition to flowering and the annotation of which have allowed us to infer the involvement of at least three hormonal pathways: those that involve abscisic acid (ABA), auxin and jasmonic acid (JA) in the regulation of floral initiation process in soybean. Intriguingly, the induction of known floral homeiotic transcript that includes APETALA1 in the SAM occurred after the induction of these hormonal transcripts adding a likely novel biochemical dimension to the current understanding of floral regulatory pathways. In view of recent studies, a cross-regulatory mechanism involving these hormones is proposed to operate at the SAM to initiate flowering.