A genetic access to plant cell axis formation

Abstract

The formation of a functional body pattern by plant cells became the subject of large-scale genetic approaches in the early 1990s. Various concepts, which either excluded or included plant hormones, were debated for several years before the focus shifted to partly self-regulatory mechanisms that could involve polar auxin flow in both cellular and organismal axis formation. A publication by Przemeck et al. contributed to this shift by explaining the embryo patterning function of the gene MONOPTEROS (MP) as part of a more general role in promoting cellular axis formation. Directional auxin flow was considered as a mechanism for aligning cell axialization along the apical-basal body axis and the MP gene was later found to encode a member of the Auxin Response Factor ( ARF ) family. The subsequent molecular elucidation of the signal transduction and transport mechanisms for auxin and other hormones made it possible to track hormone signalling much more precisely and, in many cases, to integrate hormone signals into models of plant pattern formation.