EZ-Rhizo software: the gateway to root architecture analysis.

Plants are sessile organisms that have to cope with the available nutritional resources and environmental constraints in the place where they germinate. To fully exploit their nearby resources, they have evolved a highly plastic and responsive root system. Adaptations to limited nutrients include a wide range of specific root responses, e.g., the emergence of new root types, root branching or specific growth of lateral roots. These root system architecture (RSA) features are of utmost importance when investigating the underlying mechanisms by forward, reverse or quantitative genetic approaches. The EZ-Rhizo software was developed to facilitate such root measurements in a fast, simple and accurate way. The performances of EZ-Rhizo in providing about 20 primary and derived RSA parameters were illustrated by looking at natural variability across 23 Arabidopsis accessions. The different RSA profiles obtained from plants grown in favorable condition illustrated the wide reservoir of natural genetic resources underlying specific features of root growth. This diversity was used here to correlate the RSA genetic variability with growth, development and environmental properties of accession origins.