Auxin Control of Root Development

Abstract

A plant's roots system determines both the capacity of a sessile organism to acquire nutrients and water, as well as providing a means to monitor the soil for a range of environmental conditions. Since auxins were first described, there has been a tight connection between this class of hormones and root development. Here we review some of the latest genetic, molecular, and cellular experiments that demonstrate the importance of generating and maintaining auxin gradients during root development. Refinements in the ability to monitor and measure auxin levels in root cells coupled with advances in our understanding of the sources of auxin that contribute to these pools represent important contributions to our understanding of how this class of hormones participates in the control of root development. In addition, we review the role of identified molecular components that convert auxin gradients into local differentiation events, which ultimately defines the root architecture.

Indole-3-acetic acid: A widespread physiological code in interactions of fungi with other organisms

“…45,46 IAA stimulates dose-dependent increase in the length of epidermal-derived root hairs, formation of lateral roots, and development of adventitious roots. 47 The bimodal effect of IAA level on the primary root length has been observed. 47 The shoot apical meristem generates all the aboveground organs of the plant, including leaves and flowers.…”

“…47 The bimodal effect of IAA level on the primary root length has been observed. 47 The shoot apical meristem generates all the aboveground organs of the plant, including leaves and flowers. Apical dominance is the control exerted by a shoot apex over the outgrowth of lateral buds.…”

The Folylpolyglutamate Synthetase Plastidial Isoform Is Required for Postembryonic Root Development in Arabidopsis

“…In Arabidopsis roots, local auxin concentration gradients have been shown to direct patterns of cell division, expansion, and differentiation in the root apex (Overvoorde et al, 2010). Therefore, we investigated whether the root defects of atdfb were associated with altered local auxin gradi- ents.…”

Understanding the role of Oryza sativa OsPILS (PIN Like) genes in auxin signaling

“…Auxin (indole-3-acetic acid) is one of the most important phytohormone found in plants and has unique position among plants as growth regulatory substances (Dubrovsky et al 2008;Ikeda et al 2009;Möller and Weijers 2009;Halliday et al 2009;Scarpella et al 2010;Krupinski and Jönsson 2010;McSteen 2010;Overvoorde et al 2010). Auxin acts as a prominent signaling molecule, provided by its local accumulation or depletion in selected cells, a spatial and temporal reference for changes in developmental programmes.…”