Phyllotaxis: from patterns of organogenesis at the meristem to shoot architecture

The primary architecture of the aerial part of plants is controlled by the shoot apical meristem, a specialized tissue containing a stem cell niche. The iterative generation of new aerial organs, (leaves, lateral inflorescences, and flowers) at the meristem follows regular patterns, called phyllotaxis. Phyllotaxis has long been proposed to self‐organize from the combined action of growth and of inhibitory fields blocking organogenesis in the vicinity of existing organs in the meristem. In this review, we will highlight how a combination of mathematical/computational modeling and experimental biology has demonstrated that the spatiotemporal distribution of the plant hormone auxin controls both organogenesis and the establishment of inhibitory fields. We will discuss recent advances showing that auxin likely acts through a combination of biochemical and mechanical regulatory mechanisms that control not only the pattern of organogenesis in the meristem but also postmeristematic growth, to shape the shoot. WIREs Dev Biol 2016, 5:460–473. doi: 10.1002/wdev.231 This article is categorized under: Establishment of Spatial and Temporal Patterns > Repeating Patterns and Lateral Inhibition Gene Expression and Transcriptional Hierarchies > Quantitative Methods and Models Plant Development > Inflorescence, Flower, and Fruit Development