scholarly journals Signaling pathways underlying nitrogen-dependent changes in root system architecture: from model to crop species

2020 ◽  
Vol 71 (15) ◽  
pp. 4393-4404 ◽  
Author(s):  
Zhongtao Jia ◽  
Nicolaus von Wirén
Keyword(s):  
Nutritional Status ◽  
Root System ◽  
System Architecture ◽  
Molecular Mechanisms ◽  
N Uptake ◽  
Root System Architecture ◽  
Water Soluble ◽  
Organic N ◽  
Limiting Factor ◽  
Crop Species

Abstract Among all essential mineral elements, nitrogen (N) is required in the largest amounts and thus is often a limiting factor for plant growth. N is taken up by plant roots in the form of water-soluble nitrate, ammonium, and, depending on abundance, low-molecular weight organic N. In soils, the availability and composition of these N forms can vary over space and time, which exposes roots to various local N signals that regulate root system architecture in combination with systemic signals reflecting the N nutritional status of the shoot. Uncovering the molecular mechanisms underlying N-dependent signaling provides great potential to optimize root system architecture for the sake of higher N uptake efficiency in crop breeding. In this review, we summarize prominent signaling mechanisms and their underlying molecular players that derive from external N forms or the internal N nutritional status and modulate root development including root hair formation and gravitropism. We also compare the current state of knowledge of these pathways between Arabidopsis and graminaceous plant species.

scholarly journals Controlling The Root System Architecture In Rice: Impact of Genes, Phytohormones And Root Microbiota

2021 ◽  
Author(s):  
Pankaj K Verma ◽  
Shikha Verma ◽  
Nalini Pandey
Keyword(s):  
Root System ◽  
System Architecture ◽  
Hormonal Regulation ◽  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Root Systems ◽  
Root System Architecture ◽  
World Food Security ◽  
The Impact ◽  
Root Microbiota

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.

scholarly journals Complementary Phenotyping of Maize Root System Architecture by Root Pulling Force and X-Ray Imaging

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
M. R. Shao ◽  
N. Jiang ◽  
M. Li ◽  
A. Howard ◽  
K. Lehner ◽  
...  
Keyword(s):  
Root System ◽  
System Architecture ◽  
Abiotic Stress Tolerance ◽  
3D Models ◽  
Developmental Time ◽  
Root System Architecture ◽  
Maize Root ◽  
Crop Species ◽  
X Ray ◽  
Pulling Force

The root system is critical for the survival of nearly all land plants and a key target for improving abiotic stress tolerance, nutrient accumulation, and yield in crop species. Although many methods of root phenotyping exist, within field studies, one of the most popular methods is the extraction and measurement of the upper portion of the root system, known as the root crown, followed by trait quantification based on manual measurements or 2D imaging. However, 2D techniques are inherently limited by the information available from single points of view. Here, we used X-ray computed tomography to generate highly accurate 3D models of maize root crowns and created computational pipelines capable of measuring 71 features from each sample. This approach improves estimates of the genetic contribution to root system architecture and is refined enough to detect various changes in global root system architecture over developmental time as well as more subtle changes in root distributions as a result of environmental differences. We demonstrate that root pulling force, a high-throughput method of root extraction that provides an estimate of root mass, is associated with multiple 3D traits from our pipeline. Our combined methodology can therefore be used to calibrate and interpret root pulling force measurements across a range of experimental contexts or scaled up as a stand-alone approach in large genetic studies of root system architecture.

scholarly journals Control of root system architecture by phytohormones and environmental signals in rice

2020 ◽  
Vol 67 (1-2) ◽  
pp. 98-109
Author(s):  
Chen Lin ◽  
Margret Sauter
Keyword(s):  
Root System ◽  
System Architecture ◽  
Crop Production ◽  
Molecular Mechanisms ◽  
Extreme Environments ◽  
Root System Architecture ◽  
Environmental Signals ◽  
Production Water ◽  
Environmental Extremes ◽  
Crown Roots

Drought and flooding are environmental extremes and major threats to crop production. Water uptake is achieved by plant roots which have to explore new soil spaces to alleviate water deficit during drought or to cope with water excess during flooding. Adaptation of the root system architecture helps plants cope with such extreme conditions and is crucial for plant health and survival. While for dicot plants the well studied model plant Arabidopsis thaliana has provided insight into the genetic and molecular regulation of the root system, less information is available for monocot species, which include the agronomically important cereal crops. Rice (Oryza sativa L.) is a semi-aquatic monocot plant that develops strong tolerance to flooding. Flooding tolerance of rice is closely linked to its adaptive root system. The functional root system of rice is mainly composed of crown roots and is shifted to nodal adventitious roots during flooding which allows rice to maintain oxygen supply to the roots and to survive longer periods of partial submergence as compared with other crops. Likewise, a number of drought-tolerance traits of rice are the result of an altered root system architecture. Hence, the structure of the root system adapts to, both, flooding and drought. Understanding the regulatory mechanisms that control root system adaptation to extreme environments is a key task for scientists to accelerate the breeding efforts for stress-tolerant crops. This review summarizes recently identified genes and molecular mechanisms that regulate root system architecture in rice in response to drought and flooding.

scholarly journals Enhancing crop productivity by CRISPR-mediated genetic improvement of root architecture: a focus on phytohormones

2021 ◽  
Author(s):  
Nikola Kořínková ◽  
Irene Maria Fontana ◽  
Thu Nguyen ◽  
Pouneh Pouramini ◽  
Véronique Bergougnoux ◽  
...  
Keyword(s):  
Root System ◽  
System Architecture ◽  
Crop Production ◽  
Molecular Mechanisms ◽  
Daily Intake ◽  
Crop Productivity ◽  
Root System Architecture ◽  
Future Research ◽  
Limited Attention ◽  
Technical Advances

Food security is one of the main topics of today’s agriculture especially facing challenging environmental conditions. As most humankind has a daily intake of cereal grains, current breeding programs focus on these crop plants. Within the breeders’ toolbox, customised endonucleases became included after this universal application had been demonstrated. Due to technological restrictions, the main focus was on aboveground plant organs, while the essential belowground has been given only limited attention. In the present review, we summarise the knowledge on the root system architecture in cereals, the importance of phytohormones in this physiological process, and the molecular mechanisms involved. The review summarises how the use of the CRISPR methodology can improve the root system architecture to enhance crop production genetically. Finally, future research directions involving all this knowledge and technical advances are suggested.

scholarly journals The Plasticity of Root Systems in Response to External Phosphate

2020 ◽  
Vol 21 (17) ◽  
pp. 5955 ◽  
Author(s):  
Guoqiang Huang ◽  
Dabing Zhang
Keyword(s):  
Root System ◽  
System Architecture ◽  
Molecular Mechanisms ◽  
Primary Root ◽  
Root Systems ◽  
Root System Architecture ◽  
Molecular Signaling ◽  
Post Translational Modification ◽  
Phosphate Availability ◽  
Long Time

Phosphate is an essential macro-element for plant growth accumulated in the topsoil. The improvement of phosphate uptake efficiency via manually manipulating root system architecture is of vital agronomic importance. This review discusses the molecular mechanisms of root patterning in response to external phosphate availability, which could be applied on the alleviation of phosphate-starvation stress. During the long time evolution, plants have formed sophisticated mechanisms to adapt to environmental phosphate conditions. In terms of root systems, plants would adjust their root system architecture via the regulation of the length of primary root, the length/density of lateral root and root hair and crown root growth angle to cope with different phosphate conditions. Finally, plants develop shallow or deep root system in low or high phosphate conditions, respectively. The plasticity of root system architecture responds to the local phosphate concentrations and this response was regulated by actin filaments, post-translational modification and phytohormones such as auxin, ethylene and cytokinin. This review summarizes the recent progress of adaptive response to external phosphate with focus on integrated physiological, cellular and molecular signaling transduction in rice and Arabidopsis.

scholarly journals Visualization of Arabidopsis Root System Architecture in 3D by Refraction-Contrast X-Ray Micro-Computed Tomography

Microscopy ◽  
2021 ◽  
Author(s):  
Tomofumi Kurogane ◽  
Daisuke Tamaoki ◽  
Sachiko Yano ◽  
Fumiaki Tanigaki ◽  
Toru Shimazu ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Root System ◽  
System Architecture ◽  
Root Systems ◽  
Root System Architecture ◽  
Field Of View ◽  
Imaging Method ◽  
Wide Field ◽  
Crop Species ◽  
X Ray

Abstract Plant roots change their morphological traits in order to adapt themselves to different environmental conditions, resulting in alteration of the root system architecture. To understand this mechanism, it is essential to visualize morphology of the entire root system. To reveal effects of long-term alteration of gravity environment on root system development, we have performed an experiment in the International Space Station using Arabidopsis plants and obtained dried root systems grown in rockwool slabs. X-ray computed tomography (CT) technique using industrial X-ray scanners has been introduced to visualize root system architecture of crop species grown in soil in 3D non-invasively. In the case of the present study, however, root system of Arabidopsis is composed of finer roots compared with typical crop plants and rockwool is also composed of fibers having similar dimension to that of the roots. A higher spatial resolution imaging method is required for distinguishing roots from rockwool. Therefore, in the present study, we tested refraction-contrast X-ray micro-CT using coherent X-ray optics available at the beamline of the synchrotron radiation facility SPring-8 for bio-imaging. We have found that wide field of view but with low resolution obtained at the experimental Hutch 3 of this beamline provided an overview map of the root systems, while narrow field of view but with high resolution obtained at the experimental Hutch 1 provided extended architecture of the secondary roots, by clear distinction between roots and individual rockwool fibers, resulting in successful tracing of these roots from their basal regions.

scholarly journals Complementary Phenotyping of Maize Root Architecture by Root Pulling Force and X-Ray Computed Tomography

2021 ◽  
Author(s):  
Mon-Ray Shao ◽  
Ni Jiang ◽  
Mao Li ◽  
Anne Howard ◽  
Kevin Lehner ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Root System ◽  
System Architecture ◽  
Abiotic Stress Tolerance ◽  
Root System Architecture ◽  
Maize Root ◽  
Crop Species ◽  
X Ray ◽  
X Ray Computed ◽  
Pulling Force

ABSTRACTThe root system is critical for the survival of nearly all land plants and a key target for improving abiotic stress tolerance, nutrient accumulation, and yield in crop species. Although many methods of root phenotyping exist, within field studies one of the most popular methods is the extraction and measurement of the upper portion of the root system, known as the root crown, followed by trait quantification based on manual measurements or 2D imaging. However, 2D techniques are inherently limited by the information available from single points of view. Here, we used X-ray computed tomography to generate highly accurate 3D models of maize root crowns and created computational pipelines capable of measuring 71 features from each sample. This approach improves estimates of the genetic contribution to root system architecture, and is refined enough to detect various changes in global root system architecture over developmental time as well as more subtle changes in root distributions as a result of environmental differences. We demonstrate that root pulling force, a high-throughput method of root extraction that provides an estimate of root biomass, is associated with multiple 3D traits from our pipeline. Our combined methodology can therefore be used to calibrate and interpret root pulling force measurements across a range of experimental contexts, or scaled up as a stand-alone approach in large genetic studies of root system architecture.

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.

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