New interactions between classical plant hormones

Research on the classical plant hormones continues to uncover fascinating interactions between these crucial regulatory compounds. Recent papers describe 'cross-talk' between the abscisic acid and ethylene signaling pathways in Arabidopsis, and how the nature of this interaction depends on organ type. Auxin has now been shown to promote the biosynthesis of active gibberellin in pea, by up-regulating mRNA levels of Mendel's famous stem length gene, LE. These discoveries highlight how interactions can affect signal transduction or hormone biosynthesis.