Functional phenomics and genetics of the root economics space in winter wheat using high‐throughput phenotyping of respiration and architecture

Abstract

The root economics space is a useful framework for plant ecology but is rarely considered for crop ecophysiology. In order to understand root trait integration in winter wheat, we combined functional phenomics with trait economic theory, utilizing genetic variation, highthroughput phenotyping, and multivariate analyses.We phenotyped a diversity panel of 276 genotypes for root respiration and architectural traits using a novel high-throughput method for CO 2 flux and the open-source software RHIZOVISION EXPLORER to analyze scanned images.We uncovered substantial variation in specific root respiration (SRR) and specific root length (SRL), which were primary indicators of root metabolic and structural costs. Multiple linear regression analysis indicated that lateral root tips had the greatest SRR, and the residuals from this model were used as a new trait. Specific root respiration was negatively correlated with plant mass. Network analysis, using a Gaussian graphical model, identified root weight, SRL, diameter, and SRR as hub traits. Univariate and multivariate genetic analyses identified genetic regions associated with SRR, SRL, and root branching frequency, and proposed gene candidates.Combining functional phenomics and root economics is a promising approach to improving our understanding of crop ecophysiology. We identified root traits and genomic regions that could be harnessed to breed more efficient crops for sustainable agroecosystems.

Omics-Facilitated Crop Improvement for Climate Resilience and Superior Nutritive Value

“…Then, the identified genes can be manipulated via GAB, reverse or forward genetics approaches, or gene editing techniques to develop crops with customized RSA (reviewed in Paez-Garcia et al, 2015 ). For example, Guo et al (2020) combined functional phenomics and root economics space analysis approach in winter wheat and identified some root traits, viz., specific root respiration (SRR) and specific root length (SRL), and genomic regions underlying these traits. In particular, they discovered significant variation in SRR and SRL, which were the key aspects of root metabolic and structural costs, respectively.…”

“…GWASs for the univariate traits identified numerous underlying genetic regions whereas multivariate and PCA-based GWASs offered an enhanced ability to identify the genetics of the root economics space. Moreover, they identified several SNPs linked to these traits that could be used as vital tools for marker-assisted breeding ( Guo et al, 2020 ).…”

Carbon budgeting belowground

“…Fig. 1 Imagining the phenotyping 'space' occupied by Guo et al (2021;doi: 10.1111/nph.17329) in the recently published article in New Phytologist and how it could be expanded with further research. Guo et al create a high dimensional phenotyping space in root architecture and respiration to the seedling stage using functional phenomics.…”

“…The challenge is in connecting the architecture and physiology of the root system to the use of that carbon budget; that is, finding the 'trade-offs' between root traits where the capture and use of resources is optimized. In the recently published article in New Phytologist, Guo et al (2021; doi: 10.1111/ nph.17329) present a phenotyping methodology that does just that, combining root architecture and root respiration to assess the 'economics' of root system development.…”

“…In this issue of New Phytologist , Guo et al . (2021; pp. 98–112) present a phenotyping methodology that does just that, combining root architecture and root respiration to assess the ‘economics’ of root system development.

‘One can equally imagine using this research to optimize a root system for broadacre cropping as to creating grain‐and‐graze varieties that commit resources belowground to improve soil health for a “regenerative agriculture” paradigm.’

…”