scholarly journals Neutron computed laminography yields 3D root system architecture and complements investigations of spatiotemporal rhizosphere patterns

2021 ◽  
Author(s):  
Nicole Rudolph-Mohr ◽  
Sarah Bereswill ◽  
Christian Tötzke ◽  
Nikolay Kardjilov ◽  
Sascha E. Oswald
Keyword(s):  
Root System ◽  
System Architecture ◽  
Neutron Radiography ◽  
Root Exudation ◽  
Quantitative Description ◽  
Root System Architecture ◽  
New Combination ◽  
Computed Laminography ◽  
Wide Range ◽  
Over Time

Abstract Purpose Root growth, respiration, water uptake as well as root exudation induce biogeochemical patterns in the rhizosphere that can change dynamically over time. Our aim is to develop a method that provides complementary information on 3D root system architecture and biogeochemical gradients around the roots needed for the quantitative description of rhizosphere processes. Methods We captured for the first time the root system architecture of maize plants grown in rectangular rhizotrons in 3D using neutron computed laminography (NCL). Simultaneously, we measured pH and oxygen concentration using fluorescent optodes and the 2D soil water distribution by means of neutron radiography. We co-registered the 3D laminography data with the 2D oxygen and pH maps to analyze the sensor signal as a function of the distance between the roots and the optode. Results The 3D root system architecture was successfully segmented from the laminographic data. We found that exudation of roots in up to 2 mm distance to the pH optode induced patterns of local acidification or alkalization. Over time, oxygen gradients in the rhizosphere emerged for roots up to a distance of 7.5 mm. Conclusion Neutron computed laminography allows for a three-dimensional investigation of root systems grown in laterally extended rhizotrons as the ones designed for 2D optode imaging studies. The 3D information on root position within the rhizotrons derived by NCL explained measured 2D oxygen and pH distribution. The presented new combination of 3D and 2D imaging methods facilitates systematical investigations of a wide range of dynamic processes in the rhizosphere.

Imaging biogeochemical gradients in the rhizosphere

2020 ◽  
Author(s):  
Nicole Rudolph-Mohr ◽  
Sarah Bereswill ◽  
Christian Tötzke ◽  
Nikolay Kardjilov ◽  
Sascha E. Oswald
Keyword(s):  
Water Content ◽  
Root System ◽  
Oxygen Concentration ◽  
System Architecture ◽  
Root Length Density ◽  
Lateral Roots ◽  
Root Exudation ◽  
Rapid Change ◽  
Root System Architecture ◽  
Living Plant

<p>Dynamic processes occurring at the soil-root interface crucially influence soil physical, chemical, and biological properties at local scale around the roots that are technically challenging to capture in situ. Combining 2D optodes and 3D neutron laminography, we developed a new imaging approach capable of simultaneously quantifying H<sub>2</sub>O-, O<sub>2</sub>-, and pH-distribution around living plant roots while additionally capturing the root system architecture in 3D. The interrelated patterns of root growth and distribution in soil, root respiration, root exudation, and root water uptake can be studied non-destructively at high temporal and spatial resolution.</p><p>Neutron computed laminography (NCL), a tomographic approach specially adapted to samples with large lateral extension (here 15 x 15 x 1.5 cm) was applied to visualize the root architecture and soil water content three-dimensionally. Optodes, sensitive to pH and O<sub>2</sub> changes, were attached at the inner-sides of thin boron-less glass-containers where one maize plant was grown in each container. Knowledge about the distance of the roots from the container walls and thus from the optodes, support the interpretation of the optical images.</p><p>Neutron laminography made it possible to visualize and quantify the 3D root system architecture in association with the observed H<sub>2</sub>O, pH and oxygen patterns. The older part of the root system with higher root length density was associated with fast decrease of water content and rapid change in oxygen concentration. Lateral roots acidified their rhizosphere by a quarter of a pH unit and crown root even induced acidification of up to one pH unit compared to bulk soil. The benefit of neutron laminography is that we can extract the root structure in 3D, identify root age and root types and relate this to spatiotemporal changes in water content distribution, oxygen concentration and pH values.</p>

scholarly journals Comprehensive Genome-Wide Association Analysis Reveals the Genetic Basis of Root System Architecture in Soybean

2020 ◽  
Vol 11 ◽  
Author(s):  
Waldiodio Seck ◽  
Davoud Torkamaneh ◽  
François Belzile
Keyword(s):  
Root System ◽  
System Architecture ◽  
Phenotypic Variation ◽  
Genetic Basis ◽  
Genome Wide Association Study ◽  
Primary Root ◽  
Root System Architecture ◽  
Genome Wide Association ◽  
Nucleotide Polymorphisms ◽  
Genome Wide

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.

scholarly journals Genome-wide association analysis unveils novel QTLs for seminal root system architecture traits in Ethiopian durum wheat

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Admas Alemu ◽  
Tileye Feyissa ◽  
Marco Maccaferri ◽  
Giuseppe Sciara ◽  
Roberto Tuberosa ◽  
...  
Keyword(s):  
Durum Wheat ◽  
Root System ◽  
System Architecture ◽  
Root Length ◽  
Dry Weight ◽  
Root System Architecture ◽  
High Density ◽  
Soil Conditions ◽  
Root Dry Weight ◽  
Seminal Roots

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.

Changes induced by lead in root system architecture of Arabidopsis seedlings are mediated by PDR2-LPR1/2 phosphate dependent way

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

scholarly journals Root System Architecture Plasticity of Bread Wheat in Response to Oxidative Burst under Extended Osmotic Stress

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 939
Author(s):  
Omar Azab ◽  
Abdullah Al-Doss ◽  
Thobayet Alshahrani ◽  
Salah El-Hendawy ◽  
Adel M. Zakri ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Membrane Potential ◽  
Osmotic Stress ◽  
Root System ◽  
Bread Wheat ◽  
System Architecture ◽  
Mitochondrial Membrane ◽  
Root System Architecture ◽  
Root Tips ◽  
Scavenging Capacity

There is a demand for an increase in crop production because of the growing population, but water shortage hinders the expansion of wheat cultivation, one of the most important crops worldwide. Polyethylene glycol (PEG) was used to mimic drought stress due to its high osmotic potentials generated in plants subjected to it. This study aimed to determine the root system architecture (RSA) plasticity of eight bread wheat genotypes under osmotic stress in relation to the oxidative status and mitochondrial membrane potential of their root tips. Osmotic stress application resulted in differences in the RSA between the eight genotypes, where genotypes were divided into adapted genotypes that have non-significant decreased values in lateral roots number (LRN) and total root length (TRL), while non-adapted genotypes have a significant decrease in LRN, TRL, root volume (RV), and root surface area (SA). Accumulation of intracellular ROS formation in root tips and elongation zone was observed in the non-adapted genotypes due to PEG-induced oxidative stress. Mitochondrial membrane potential (∆Ψm) was measured for both stress and non-stress treatments in the eight genotypes as a biomarker for programmed cell death as a result of induced osmotic stress, in correlation with RSA traits. PEG treatment increased scavenging capacity of the genotypes from 1.4-fold in the sensitive genotype Gemmiza 7 to 14.3-fold in the adapted genotype Sakha 94. The adapted genotypes showed greater root trait values, ∆Ψm plasticity correlated with high scavenging capacity, and less ROS accumulation in the root tissue, while the non-adapted genotypes showed little scavenging capacity in both treatments, accompanied by mitochondrial membrane permeability, suggesting mitochondrial dysfunction as a result of oxidative stress.

scholarly journals Biochar induced improvement in root system architecture enhances nutrient assimilation by cotton plant seedlings

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lei Feng ◽  
Wanli Xu ◽  
Guangmu Tang ◽  
Meiying Gu ◽  
Zengchao Geng
Keyword(s):  
Root System ◽  
System Architecture ◽  
Fine Roots ◽  
Nitrogen Assimilation ◽  
Surface Soil ◽  
Soil Layer ◽  
Root System Architecture ◽  
Seedling Stage ◽  
Agronomic Efficiency ◽  
Surface Soil Layer

Abstract Background Raising nitrogen use efficiency of crops by improving root system architecture is highly essential not only to reduce costs of agricultural production but also to mitigate climate change. The physiological mechanisms of how biochar affects nitrogen assimilation by crop seedlings have not been well elucidated. Results Here, we report changes in root system architecture, activities of the key enzymes involved in nitrogen assimilation, and cytokinin (CTK) at the seedling stage of cotton with reduced urea usage and biochar application at different soil layers (0–10 cm and 10–20 cm). Active root absorption area, fresh weight, and nitrogen agronomic efficiency increased significantly when urea usage was reduced by 25% and biochar was applied in the surface soil layer. Glutamine oxoglutarate amino transferase (GOGAT) activity was closely related to the application depth of urea/biochar, and it increased when urea/biochar was applied in the 0–10 cm layer. Glutamic-pyruvic transaminase activity (GPT) increased significantly as well. Nitrate reductase (NR) activity was stimulated by CTK in the very fine roots but inhibited in the fine roots. In addition, AMT1;1, gdh3, and gdh2 were significantly up-regulated in the very fine roots when urea usage was reduced by 25% and biochar was applied. Conclusion Nitrogen assimilation efficiency was significantly affected when urea usage was reduced by 25% and biochar was applied in the surface soil layer at the seedling stage of cotton. The co-expression of gdh3 and gdh2 in the fine roots increased nitrogen agronomic efficiency. The synergistic expression of the ammonium transporter gene and gdh3 suggests that biochar may be beneficial to amino acid metabolism.

scholarly journals Morphological Characterization of Root System Architecture in Diverse Tomato Genotypes during Early Growth

2018 ◽  
Vol 19 (12) ◽  
pp. 3888 ◽  
Author(s):  
Aurora Alaguero-Cordovilla ◽  
Francisco Gran-Gómez ◽  
Sergio Tormos-Moltó ◽  
José Pérez-Pérez
Keyword(s):  
Root System ◽  
System Architecture ◽  
Lateral Root ◽  
Morphological Plasticity ◽  
Root System Architecture ◽  
Morphological Characterization ◽  
Early Growth ◽  
Soil Conditions ◽  
Wild Tomato Species ◽  
Local Soil

Plant roots exploit morphological plasticity to adapt and respond to different soil environments. We characterized the root system architecture of nine wild tomato species and four cultivated tomato (Solanum lycopersicum L.) varieties during early growth in a controlled environment. Additionally, the root system architecture of six near-isogenic lines from the tomato ‘Micro-Tom’ mutant collection was also studied. These lines were affected in key genes of ethylene, abscisic acid, and anthocyanin pathways. We found extensive differences between the studied lines for a number of meaningful morphological traits, such as lateral root distribution, lateral root length or adventitious root development, which might represent adaptations to local soil conditions during speciation and subsequent domestication. Taken together, our results provide a general quantitative framework for comparing root system architecture in tomato seedlings and other related species.

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