scholarly journals The impact of the rhizobia–legume symbiosis on host root system architecture

2020 ◽  
Vol 71 (13) ◽  
pp. 3902-3921 ◽  
Author(s):  
Cristobal Concha ◽  
Peter Doerner

Abstract Legumes form symbioses with rhizobia to fix N2 in root nodules to supplement their nitrogen (N) requirements. Many studies have shown how symbioses affect the shoot, but far less is understood about how they modify root development and root system architecture (RSA). RSA is the distribution of roots in space and over time. RSA reflects host resource allocation into below-ground organs and patterns of host resource foraging underpinning its resource acquisition capacity. Recent studies have revealed a more comprehensive relationship between hosts and symbionts: the latter can affect host resource acquisition for phosphate and iron, and the symbiont’s production of plant growth regulators can enhance host resource flux and abundance. We review the current understanding of the effects of rhizobia–legume symbioses on legume root systems. We focus on resource acquisition and allocation within the host to conceptualize the effect of symbioses on RSA, and highlight opportunities for new directions of research.

2012 ◽  
Vol 110 (2) ◽  
pp. 511-519 ◽  
Author(s):  
Saoirse R. Tracy ◽  
Colin R. Black ◽  
Jeremy A. Roberts ◽  
Craig Sturrock ◽  
Stefan Mairhofer ◽  
...  

2021 ◽  
Author(s):  
Pankaj K Verma ◽  
Shikha Verma ◽  
Nalini Pandey

Abstract BackgroundIn order to feed expanding population, new crop varieties were generated which significantly contribute to world food security. However, the growth of these improved plants varieties relied primarily on synthetic fertilizers, which negatively affect the environment as well as human health. Plants adapt to adverse environmental changes by adopting root systems through architectural changes at the root-type and tissue-specific changes and nutrient uptake efficiency. ScopePlants adapt and operate distinct pathways at various stages of development in order to optimally establish their root systems, such as change in the expression profile of genes, changes in phytohormone level and microbiome induced Root System Architecture (RSA) modification. Many scientific studies have been carried out to understand plant response to microbial colonization and how microbes involved in RSA improvement through phytohormone level and transcriptomic changes.ConclusionIn this review, we spotlight the impact of genes, phytohormones and root microbiota on RSA and provide specific, critical new insights that have been resulted from recent studies on rice root as a model. First, we discuss new insights into the genetic regulation of RSA. Next, hormonal regulation of root architecture and the impact of phytohormones in crown root and root branching is discussed. Finally, we discussed the impact of root microbiota in RSA modification and summarized the current knowledge about the biochemical and central molecular mechanisms involved.


2021 ◽  
Author(s):  
Therese LaRue ◽  
Heike Lindner ◽  
Ankit Srinivas ◽  
Moises Exposito-Alonso ◽  
Guillaume Ramon Lobet ◽  
...  

The plant kingdom contains a stunning array of complex morphologies easily observed above ground, but largely unexplored below-ground. Understanding the magnitude of diversity in root distribution within the soil, termed root system architecture (RSA), is fundamental to determining how this trait contributes to species adaptation in local environments. Roots are the interface between the soil environment and the shoot system and therefore play a key role in anchorage, resource uptake, and stress resilience. Previously, we presented the GLO-Roots (Growth and Luminescence Observatory for Roots) system to study the RSA of soil-grown Arabidopsis thaliana plants from germination to maturity. In this study, we present the automation of GLO-Roots using robotics and the development of image analysis pipelines in order to examine the natural variation of RSA in Arabidopsis over time. This dataset describes the developmental dynamics of 93 accessions and reveals highly complex and polygenic RSA traits that show significant correlation with climate variables.


2020 ◽  
Vol 227 (2) ◽  
pp. 376-391 ◽  
Author(s):  
Daniel M. McKay Fletcher ◽  
Siul Ruiz ◽  
Tiago Dias ◽  
Chiara Petroselli ◽  
Tiina Roose

2020 ◽  
Vol 11 ◽  
Author(s):  
Waldiodio Seck ◽  
Davoud Torkamaneh ◽  
François Belzile

Increasing the understanding genetic basis of the variability in root system architecture (RSA) is essential to improve resource-use efficiency in agriculture systems and to develop climate-resilient crop cultivars. Roots being underground, their direct observation and detailed characterization are challenging. Here, were characterized twelve RSA-related traits in a panel of 137 early maturing soybean lines (Canadian soybean core collection) using rhizoboxes and two-dimensional imaging. Significant phenotypic variation (P < 0.001) was observed among these lines for different RSA-related traits. This panel was genotyped with 2.18 million genome-wide single-nucleotide polymorphisms (SNPs) using a combination of genotyping-by-sequencing and whole-genome sequencing. A total of 10 quantitative trait locus (QTL) regions were detected for root total length and primary root diameter through a comprehensive genome-wide association study. These QTL regions explained from 15 to 25% of the phenotypic variation and contained two putative candidate genes with homology to genes previously reported to play a role in RSA in other species. These genes can serve to accelerate future efforts aimed to dissect genetic architecture of RSA and breed more resilient varieties.


BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Admas Alemu ◽  
Tileye Feyissa ◽  
Marco Maccaferri ◽  
Giuseppe Sciara ◽  
Roberto Tuberosa ◽  
...  

Abstract Background Genetic improvement of root system architecture is essential to improve water and nutrient use efficiency of crops or to boost their productivity under stress or non-optimal soil conditions. One hundred ninety-two Ethiopian durum wheat accessions comprising 167 historical landraces and 25 modern cultivars were assembled for GWAS analysis to identify QTLs for root system architecture (RSA) traits and genotyped with a high-density 90 K wheat SNP array by Illumina. Results Using a non-roll, paper-based root phenotyping platform, a total of 2880 seedlings and 14,947 seminal roots were measured at the three-leaf stage to collect data for total root length (TRL), total root number (TRN), root growth angle (RGA), average root length (ARL), bulk root dry weight (RDW), individual root dry weight (IRW), bulk shoot dry weight (SDW), presence of six seminal roots per seedling (RT6) and root shoot ratio (RSR). Analysis of variance revealed highly significant differences between accessions for all RSA traits. Four major (− log10P ≥ 4) and 34 nominal (− log10P ≥ 3) QTLs were identified and grouped in 16 RSA QTL clusters across chromosomes. A higher number of significant RSA QTL were identified on chromosome 4B particularly for root vigor traits (root length, number and/or weight). Conclusions After projecting the identified QTLs on to a high-density tetraploid consensus map along with previously reported RSA QTL in both durum and bread wheat, fourteen nominal QTLs were found to be novel and could potentially be used to tailor RSA in elite lines. The major RGA QTLs on chromosome 6AL detected in the current study and reported in previous studies is a good candidate for cloning the causative underlining sequence and identifying the beneficial haplotypes able to positively affect yield under water- or nutrient-limited conditions.


BioMetals ◽  
2021 ◽  
Author(s):  
Ricardo Ortiz-Luevano ◽  
José López-Bucio ◽  
Miguel Martínez-Trujillo ◽  
Lenin Sánchez-Calderón

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