GLO-Roots: an imaging platform enabling multidimensional characterization of soil-grown root systems

Abstract

Root systems develop different root types that individually sense cues from their local environment and integrate this information with systemic signals. This complex multi-dimensional amalgam of inputs enables continuous adjustment of root growth rates, direction, and metabolic activity that define a dynamic physical network. Current methods for analyzing root biology balance physiological relevance with imaging capability. To bridge this divide, we developed an integrated-imaging system called Growth and Luminescence Observatory for Roots (GLO-Roots) that uses luminescence-based reporters to enable studies of root architecture and gene expression patterns in soil-grown, light-shielded roots. We have developed image analysis algorithms that allow the spatial integration of soil properties, gene expression, and root system architecture traits. We propose GLO-Roots as a system that has great utility in presenting environmental stimuli to roots in ways that evoke natural adaptive responses and in providing tools for studying the multi-dimensional nature of such processes.DOI: http://dx.doi.org/10.7554/eLife.07597.001

Growing Out of Stress: The Role of Cell- and Organ-Scale Growth Control in Plant Water-Stress Responses

“…Correlated with these structural and physiological differences, the response to abiotic stress has also been shown to distinguish the organs of the root system. Exposure to water deficit during early lateral root (LR) development revealed inhibition of postemergence growth in Arabidopsis (Xiong et al, 2006;Rellán-Álvarez et al, 2015), involving ABA and auxin signaling (Deak and Malamy, 2005;Xiong et al, 2006). Therefore, water deficit causes a clear reduction in root mass in more mature root systems (Xiong et al, 2006;Rellán-Álvarez et al, 2015).…”

“…Exposure to water deficit during early lateral root (LR) development revealed inhibition of postemergence growth in Arabidopsis (Xiong et al, 2006;Rellán-Álvarez et al, 2015), involving ABA and auxin signaling (Deak and Malamy, 2005;Xiong et al, 2006). Therefore, water deficit causes a clear reduction in root mass in more mature root systems (Xiong et al, 2006;Rellán-Álvarez et al, 2015). For salt stress, many genes and pathways have been identified over the past few decades that regulate the early response of roots at the cellular level (Julkowska and Testerink, 2015).…”

Grasses suppress shoot-borne roots to conserve water during drought

“…To explore acclimatization to water-limited growing conditions at a whole root system level, we used the newly developed luminescence-based imaging system GLO-Roots (Growth and Luminescence Observatory for Roots), which enables imaging of root systems in sheets of peat-based soil (14). Growth of plants in soil-filled rhizotrons enabled implementation of a similar WD regime as used in our pot-based experiments (Fig.…”

“…To understand how WD affects the balance between embryonic and postembryonic parts of the root system and specifically crown root development, we analyzed root growth through excavation from soil and using the GLO-Roots imaging system (14). These studies used the emerging grass model species Setaria viridis, which is a C 4 -grass model for other agronomically important panicoid grasses, such as maize and sorghum (15,16).…”

Morphological Plant Modeling: Unleashing Geometric and Topological Potential within the Plant Sciences

“…This concept infused rapidly as morphometrics into biology (Bookstein, 1997) and is increasingly carried out using machine vision techniques (Wilf et al, 2016). Kendall's idea inspired the development of methods such as elliptical Fourier descriptors (Kuhl and Giardina, 1982) and new trends employing the Laplace Beltrami operator (Reuter et al, 2009), both relying on the spectral decompositions of shapes (Chitwood et al, 2012;Laga et al, 2014;Rellán-Álvarez et al, 2015). Beyond the organ level, such morphometric descriptors were used to analyze cellular expansion rates of rapidly deforming primordia into mature organ morphologies (Rolland-Lagan et al, 2003;Remmler and Rolland-Lagan, 2012;Das Gupta and Nath, 2015).…”