From Cell Division to Organ Shape: Nitric Oxide Is Involved in Auxin-Mediated Root Development - Communication in Plants: Neuronal Aspects of Plant Life - page 123

9 From Cell Division to Organ Shape:

Nitric Oxide Is Involved
in Auxin-Mediated Root Development
María Luciana Lanteri, Magdalena Graziano,
Natalia Correa-Aragunde, Lorenzo Lamattina

Abstract Roots are plant organs that mainly function to acquire water and nutrients from
soil. Root development is under the control of a regulated cell proliferation and morpho-
genesis, and auxin is the central plant hormone that governs those processes. In this review
we discuss new aspects of the mechanisms that operate during root organogenesis. We par-
ticularly emphasize the analyses of downstream signals involved in the auxin control of root
development. Nitric oxide (NO), an emerging chemical messenger that plays a significant
role in a broad spectrum of plant developmental processes, is a key component in the signal
transduction pathways that determine root architecture. Lateral root development as well
as adventitious root formation are strictly NO-dependent processes in the auxin-promoted
root organogenesis.

9.1
Introduction

Roots are organs that accomplish a variety of biological functions. They are
the site of nutrient and water uptake and they also constitute the storage
organ in some species. Roots are in contact with a complex environment
including soil microorganisms in the rhizosphere and are, thereby, submit-
ted to a fine modulation and cross talk of information, signals and stimuli.
Roots are able to produce and to sense growth regulators, chemical mes-
sengers and metabolites that communicate to the whole plant the result of
processing and integration of that information. In this review we present
recent data concerning the downstream signals involved in auxin-regulated
mechanisms that control root growth and development. We focus on the
involvement of nitric oxide (NO) as a signal molecule leading to lateral and
adventitious root development with the aim of integrating available data
and to generate a clearer scenario for describing the cross talk between
auxins and NO.