High-throughput imaging and analysis of root system architecture inBrachypodium distachyonunder differential nutrient availability

Abstract

Nitrogen (N) and phosphorus (P) deficiency are primary constraints for plant productivity, and root system architecture (RSA) plays a vital role in the acquisition of these nutrients. The genetic determinants of RSA are poorly understood, primarily owing to the complexity of crop genomes and the lack of sufficient RSA phenotyping methods. The objective of this study was to characterize the RSA of two Brachypodium distachyon accessions under different nutrient availability. To do so, we used a high-throughput plant growth and imaging platform, and developed software that quantified 19 different RSA traits. We found significant differences in RSA between two Brachypodium accessions grown on nutrient-rich, low-N and low-P conditions. More specifically, one accession maintained axile root growth under low N, while the other accession maintained lateral root growth under low P. These traits resemble the RSA of crops adapted to low-N and -P conditions, respectively. Furthermore, we found that a number of these traits were highly heritable. This work lays the foundation for future identification of important genetic components of RSA traits under nutrient limitation using a mapping population derived from these two accessions.

Plasticity of the Arabidopsis Root System under Nutrient Deficiencies

“…It is possible to represent the variation for many traits in a relatively small number of data points within the plasticity graph. Plasticity charts can condense the number of data points, particularly in studies involving modern root phenotyping techniques such as those of Ingram et al (2012), Clark et al (2011), or Iyer-Pascuzzi et al (2010 that measured between 16 and 27 root traits in a number of genotypes.…”

Root system architecture: insights fromArabidopsisand cereal crops

“…This species has many of the same benefits of Arabidopsis as a model species, such as small size, relatively short life cycle and small genome size; but crucially it has the root architecture typical of monocots, because it belongs to the family Poaceae, which also includes rice, maize, wheat and barley. Pacheco-Villalobos et al [128] and Ingram et al [129] further discuss the suitability of Brachypodium as a model for root studies.…”

Duplicate and Conquer: Multiple Homologs ofPHOSPHORUS-STARVATION TOLERANCE1Enhance Phosphorus Acquisition and Sorghum Performance on Low-Phosphorus Soils

“…Another strategy to cope with low-P availability is to increase the soil volume accessed by root systems by forming mycorrhizal symbioses Smith and Smith, 2012;Rai et al, 2013). Due to low-P mobility on tropical soils, changes in root architecture and morphology enhance P uptake by facilitating soil exploration (Williamson et al, 2001;Ho et al, 2005;Walk et al, 2006;Svistoonoff et al, 2007;Lynch, 2011;Ingram et al, 2012;Niu et al, 2013). Root structural changes leading to higher P uptake include increased root hair growth (Yan et al, 2004;Haling et al, 2013;Lan et al, 2013) and length and enhancing lateral root over primary root growth (Williamson et al, 2001;Wang et al, 2013).…”