scholarly journals Nature and Nurture: Genotype-Dependent Differential Responses of Root Architecture to Agar and Soil Environments

Genes ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 1028
Author(s):  
Merijn Kerstens ◽  
Vera Hesen ◽  
Kavya Yalamanchili ◽  
Andrea Bimbo ◽  
Stephen Grigg ◽  
...  
Keyword(s):  
Root System ◽  
Root Density ◽  
Plant Performance ◽  
Plate Versus ◽  
Routine Practice ◽  
Loss Of Function ◽  
Short Root ◽  
Total Contribution ◽  
Secondary Root ◽  
Differential Responses

Root development is crucial for plant growth and therefore a key factor in plant performance and food production. Arabidopsis thaliana is the most commonly used system to study root system architecture (RSA). Growing plants on agar-based media has always been routine practice, but this approach poorly reflects the natural situation, which fact in recent years has led to a dramatic shift toward studying RSA in soil. Here, we directly compare RSA responses to agar-based medium (plates) and potting soil (rhizotrons) for a set of redundant loss-of-function plethora (plt) CRISPR mutants with variable degrees of secondary root defects. We demonstrate that plt3plt7 and plt3plt5plt7 plants, which produce only a handful of emerged secondary roots, can be distinguished from other genotypes based on both RSA shape and individual traits on plates and rhizotrons. However, in rhizotrons the secondary root density and the total contribution of the side root system to the RSA is increased in these two mutants, effectively rendering their phenotypes less distinct compared to WT. On the other hand, plt3, plt3plt5, and plt5plt7 mutants showed an opposite effect by having reduced secondary root density in rhizotrons. This leads us to believe that plate versus rhizotron responses are genotype dependent, and these differential responses were also observed in unrelated mutants short-root and scarecrow. Our study demonstrates that the type of growth system affects the RSA differently across genotypes, hence the optimal choice of growth conditions to analyze RSA phenotype is not predetermined.

Mechanisms underlying root system architecture adaptation to low phosphate environment

2015 ◽  
Author(s):  
Sigal Savaldi-Goldstein ◽  
Siobhan M. Brady
Keyword(s):  
Root System ◽  
System Architecture ◽  
Wild Species ◽  
Root Elongation ◽  
Steroid Hormone ◽  
Root System Architecture ◽  
Iron Accumulation ◽  
Plant Performance ◽  
P Availability ◽  
New Genes

In order to advance our understanding towards potential biotechnology improvement of plant performance, we studied root responses to limited P in two different plants, Arabidopsis and tomato. Arabidopsis is among the most studied model plants that allows rapid application of molecular and developmental experiments while tomato is an important crop, with application in agriculture. Using Arabidopsis we found that steroid hormones modulate the extent of root elongation in response to limited P, by controlling the accumulation of iron in the root. We also found that the availability of P and iron control the activity of the steroid hormone in the root. Finally, we revealed the genes involved in this nutrient-hormone interaction. Hence, the ferroxidase LPR1 that promotes iron accumulation in response to low P is repressed by the transcription factor BES1/BZR1. Low P inhibits the steroid hormone pathway by enhancing the accumulation of BKI1. High levels of BKI1 inhibit the activity of the steroid hormone receptor at the cell surface and iron accumulation increases inside the root, resulting in a slow growth. Together, the extent of root elongation depends on interactions between an internal cue (steroid hormone) and cues derived from the availability of P and iron in the environment. Using tomato, we found that the response of two cultivated tomato varieties (M82 and New Yorker) to limited P is distinct from that of the wild species, Solanumpennellii. This is implicated at both the levels of root development and whole plant physiology. Specifically, while the root system architecture of cultivated tomato is modulated by limited P availability, that of the wild type species remained unaffected. The wild species appears to be always behaving as if it is always in phosphate deprived conditions, despite sufficient levels of phosphate. Hyper-accumulation of metals appears to mediate this response. Together, this knowledge will be used to isolate new genes controlling plant adaptation to limited P environment. 

scholarly journals Regulation of lateral root development by shoot-sensed far-red light via HY5 is nitrate-dependent and involves the NRT2.1 nitrate transporter

2021 ◽  
Author(s):  
Kasper van Gelderen ◽  
Chiakai Kang ◽  
Peijin Li ◽  
Ronald Pierik
Keyword(s):  
Root Growth ◽  
Root System ◽  
Lateral Root ◽  
Environmental Changes ◽  
Red Light ◽  
Agar Plate ◽  
Nitrate Transporter ◽  
Loss Of Function ◽  
Lateral Root Development ◽  
Nitrate Signaling

AbstractPlants are very effective in responding to environmental changes during competition for light and nutrients. Low Red:Far-Red (low R:FR)-mediated neighbor detection allows plants to compete successfully with other plants for available light. This above-ground signal can also reduce lateral root growth by inhibiting lateral root emergence, a process that might help the plant invest resources in shoot growth. Nitrate is an essential nutrient for plant growth and Arabidopsis thaliana responds to low nitrate conditions by enhancing nutrient uptake and reducing lateral and main root growth. There are indications that low R:FR signaling and low nitrate signaling can affect each other. It is unknown which response is prioritized when low R:FR light- and low nitrate signaling co-occur. We investigated the effect of low nitrate conditions on the low R:FR response of the A. thaliana root system in agar plate media, combined with the application of supplemental Far-Red (FR) light to the shoot. We observed that under low nitrate conditions main and lateral root growth was reduced, but more importantly, that the response of the root system to low R:FR was suppressed. Consistently, a loss-of-function mutant of a nitrate transporter gene NRT2.1 lacked low R:FR-induced lateral root reduction and its root growth was hypersensitive to low nitrate. ELONGATED HYPOCOTYL5 (HY5) plays an important role in the root response to low R:FR and we found that it was less sensitive to low nitrate conditions with regards to lateral root growth. In addition, we found that low R:FR increases NRT2.1 expression and that low nitrate enhances HY5 expression. HY5 also affects NRT2.1 expression, however, it depended on the presence of ammonium in which direction this effect was. Replacing part of the nitrogen source with ammonium also removed the effect of low R:FR on the root system, showing that changes in nitrogen sources can be crucial for root plasticity. Together our results show that nitrate signaling can repress low R:FR responses and that this involves signaling via HY5 and NRT2.1.

scholarly journals Availability of anions in the growth medium to roots of an actively growing plant.

1975 ◽  
Vol 23 (2) ◽  
pp. 131-138
Author(s):  
H. Van Keulen ◽  
N.G. Seligman ◽  
J. Goudriaan
Keyword(s):  
Root System ◽  
Growth Medium ◽  
Mass Flow ◽  
Dispersion Coefficient ◽  
Anion Transport ◽  
Root Density ◽  
High Dispersion ◽  
Rooting Zone ◽  
Speed Up ◽  
Low Dispersion

Analysis of anion transport to the root of an actively growing plant with a normally dense root system showed that virtually the whole of the anion store in the rooting zone is available to the plant within a few days at the most. Transport by diffusion only is enough to account for most of the depletion, but mass flow will speed up the process. The effect of mass flow will be considerable in soils with a high dispersion coefficient (loess), but very small in soils with a low dispersion coefficient (clay and sand). A rule is proposed to determine whether a given root density is sufficient to supply the nitrogen and water needs of the plant by diffusion only. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Barley shoot biomass responds strongly to N:P stoichiometry and intraspecific competition, whereas roots only alter their foraging

2020 ◽  
Vol 453 (1-2) ◽  
pp. 515-528 ◽  
Author(s):  
Amit Kumar ◽  
Richard van Duijnen ◽  
Benjamin M. Delory ◽  
Rüdiger Reichel ◽  
Nicolas Brüggemann ◽  
...  
Keyword(s):  
Root System ◽  
Intraspecific Competition ◽  
Root Length ◽  
Root Biomass ◽  
Specific Root Length ◽  
Plant Performance ◽  
Shoot Biomass ◽  
P Availability ◽  
Soil Layers ◽  
N:P Stoichiometry

Abstract Aims Root system responses to the limitation of either nitrogen (N) or phosphorus (P) are well documented, but how the early root system responds to (co-) limitation of one (N or P) or both in a stoichiometric framework is not well-known. In addition, how intraspecific competition alters plant responses to N:P stoichiometry is understudied. Therefore, we aimed to investigate the effects of N:P stoichiometry and competition on root system responses and overall plant performance. Methods Plants (Hordeum vulgare L.) were grown in rhizoboxes for 24 days in the presence or absence of competition (three vs. one plant per rhizobox), and fertilized with different combinations of N:P (low N + low P, low N + high P, high N + low P, and high N + high P). Results Shoot biomass was highest when both N and P were provided in high amounts. In competition, shoot biomass decreased on average by 22%. Total root biomass (per plant) was not affected by N:P stoichiometry and competition but differences were observed in specific root length and root biomass allocation across soil depths. Specific root length depended on the identity of limiting nutrient (N or P) and competition. Plants had higher proportion of root biomass in deeper soil layers under N limitation, while a greater proportion of root biomass was found at the top soil layers under P limitation. Conclusions With low N and P availability during early growth, higher investments in root system development can significantly trade off with aboveground productivity, and strong intraspecific competition can further strengthen such effects.

scholarly journals Bradyrhizobium japonicum IRAT FA3 alters Arabidopsis thaliana root architecture via regulation of auxin efflux transporters PIN2, PIN3, PIN7 and ABCB19

2021 ◽  
Author(s):  
Mercedes Schroeder ◽  
Melissa Y. Gomez ◽  
Nathan K. McLain ◽  
Emma Gachomo
Keyword(s):  
Arabidopsis Thaliana ◽  
Root System ◽  
Root Development ◽  
Bradyrhizobium Japonicum ◽  
Lateral Root ◽  
Plant Root ◽  
Primary Root ◽  
Efflux Transporters ◽  
Loss Of Function ◽  
Lateral Root Primordia

Beneficial rhizobacteria can stimulate changes in plant root development. While root system growth is mediated by multiple factors, the regulated distribution of the phytohormone auxin within root tissues plays a principal role. Auxin transport facilitators help to generate the auxin gradients and maxima that determine root structure. Here, we show that the plant growth-promoting rhizobacterial strain Bradyrhizobium japonicum IRAT FA3 influences specific auxin efflux transporters to alter Arabidopsis thaliana root morphology. Gene expression profiling of host transcripts in control and B. japonicum-inoculated roots of the wild type A. thaliana accession Col-0 confirmed upregulation of PIN2, PIN3, PIN7 and ABCB19 with B. japonicum and identified genes potentially contributing to a diverse array of auxin-related responses. Co-cultivation of the bacterium with loss-of-function auxin efflux transport mutants revealed that B. japonicum requires PIN3, PIN7 and ABCB19 to increase lateral root development and utilizes PIN2 to reduce primary root length. Accelerated lateral root primordia production due to B. japonicum was not observed in single pin3, pin7 or abcb19 mutants, suggesting independent roles for PIN3, PIN7 and ABCB19 during the plant-microbe interaction. Our work demonstrates B. japonicum’s influence over host transcriptional reprogramming during plant interaction with this beneficial microbe and the subsequent alterations to root system architecture.

scholarly journals AtRBOHC/RHD2 vesicular delivery to the apical plasma membrane domain during root hair development

2021 ◽  
Author(s):  
Lenka Kuběnová ◽  
Michaela Tichá ◽  
Jozef Šamaj ◽  
Miroslav Ovečka
Keyword(s):  
Plasma Membrane ◽  
Quantitative Analysis ◽  
Root Hair ◽  
Tip Growth ◽  
Root Hairs ◽  
Apical Plasma Membrane ◽  
Loss Of Function ◽  
Short Root ◽  
Early Endosomes ◽  
Root Hair Initiation

AbstractArabidopsis root hairs develop as long tubular extensions from the rootward pole of trichoblasts and exert polarized tip growth. The establishment and maintenance of root hair polarity is a complex process involving the local apical production of reactive oxygen species (ROS) generated by NADPH oxidase RESPIRATORY BURST OXIDASE HOMOLOG PROTEIN C/ROOT HAIR DEFECTIVE 2 (AtRBOHC/RHD2). It has been shown that loss-of-function rhd2 mutants have short root hairs that are unable to elongate by tip growth, and this phenotype was fully complemented by GFP-RHD2 expressed under the RHD2 promoter. However, the spatiotemporal mechanism of AtRBOHC/RHD2 subcellular redistribution and delivery to the plasma membrane (PM) during root hair initiation and tip growth are still unclear. Here, we used advanced microscopy for detailed qualitative and quantitative analysis of vesicular compartments containing GFP-RHD2 and characterization of their movements in developing bulges and growing root hairs. These compartments, identified by an independent marker such as the trans-Golgi network (TGN), deliver GFP-RHD2 to the apical PM domain, the extent of which correlates with the stage of root hair formation. Movements of TGN/early endosomes, but not late endosomes, were affected in the bulging domains of the rhd2-1 mutant. Finally, we reveal that accumulation in the growing tip, docking, and incorporation of TGN compartments containing GFP-RHD2 to the apical PM of root hairs requires structural sterols. These results help clarify the mechanism of polarized AtRBOHC/RHD2 targeting, maintenance, and recycling at the apical PM domain, coordinated with different developmental stages of root hair initiation and growth.One-sentence summaryAdvanced microscopy and quantitative analysis of vesicular TGN compartments revealed that delivering GFP-RHD2 to the apical plasma membrane domains of developing bulges and growing root hairs requires structural sterols.

scholarly journals Regulation of Lateral Root Development by Shoot-Sensed Far-Red Light via HY5 Is Nitrate-Dependent and Involves the NRT2.1 Nitrate Transporter

2021 ◽  
Vol 12 ◽  
Author(s):  
Kasper van Gelderen ◽  
Chiakai Kang ◽  
Peijin Li ◽  
Ronald Pierik
Keyword(s):  
Root Growth ◽  
Root System ◽  
Lateral Root ◽  
Environmental Changes ◽  
Red Light ◽  
Agar Plate ◽  
Nitrate Transporter ◽  
Loss Of Function ◽  
Lateral Root Development ◽  
Nitrate Signaling

Plants are very effective in responding to environmental changes during competition for light and nutrients. Low Red:Far-Red (low R:FR)-mediated neighbor detection allows plants to compete successfully with other plants for available light. This above-ground signal can also reduce lateral root growth by inhibiting lateral root emergence, a process that might help the plant invest resources in shoot growth. Nitrate is an essential nutrient for plant growth and Arabidopsis thaliana responds to low nitrate conditions by enhancing nutrient uptake and reducing lateral and main root growth. There are indications that low R:FR signaling and low nitrate signaling can affect each other. It is unknown which response is prioritized when low R:FR light- and low nitrate signaling co-occur. We investigated the effect of low nitrate conditions on the low R:FR response of the A. thaliana root system in agar plate media, combined with the application of supplemental Far-Red (FR) light to the shoot. We observed that under low nitrate conditions main and lateral root growth was reduced, but more importantly, that the response of the root system to low R:FR was not present. Consistently, a loss-of-function mutant of a nitrate transporter gene NRT2.1 lacked low R:FR-induced lateral root reduction and its root growth was hypersensitive to low nitrate. ELONGATED HYPOCOTYL5 (HY5) plays an important role in the root response to low R:FR and we found that it was less sensitive to low nitrate conditions with regards to lateral root growth. In addition, we found that low R:FR increases NRT2.1 expression and that low nitrate enhances HY5 expression. HY5 also affects NRT2.1 expression, however, it depended on the presence of ammonium in which direction this effect was. Replacing part of the nitrogen source with ammonium also removed the effect of low R:FR on the root system, showing that changes in nitrogen sources can be crucial for root plasticity. Together our results show that nitrate signaling can repress low R:FR responses and that this involves signaling via HY5 and NRT2.1.

scholarly journals Effect of inoculation of the plant root system by the endophyte Cylindrocarpon magnusianum on plant performance when exposed to heavy metal salts

2020 ◽  
Author(s):  
I. L. Bukharina ◽  
N. A. Islamova
Keyword(s):  
Heavy Metal ◽  
Root System ◽  
Plant Root ◽  
Metal Salts ◽  
Plant Performance ◽  
Heavy Metal Salts ◽  
Effective Partnership ◽  
Plant Root System

The effect of inoculation of Cylindrocarpon magnusianum on plants under the action of heavy metal salts was studied. Effective partnership of the fungus and plants was revealed in the conditions most extreme for the life of plants.

scholarly journals Integrating GWAS and Gene Expression Analysis Identifies Candidate Genes for Root Morphology Traits in Maize at the Seedling Stage

Genes ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 773 ◽  
Author(s):  
Wang ◽  
Wei ◽  
Li ◽  
Wang ◽  
Ge ◽  
...  
Keyword(s):  
Root System ◽  
Candidate Genes ◽  
Root Development ◽  
Root Length ◽  
Root Traits ◽  
Root Surface ◽  
Root Surface Area ◽  
Phenotypic Variance ◽  
Potential Candidate ◽  
Short Root

Root system plays an essential role in water and nutrient acquisition in plants. Understanding the genetic basis of root development will be beneficial for breeding new cultivars with efficient root system to enhance resource use efficiency in maize. Here, the natural variation of 13 root and 3 shoot traits was evaluated in 297 maize inbred lines and genome-wide association mapping was conducted to identify SNPs associated with target traits. All measured traits exhibited 2.02- to 21.36-fold variations. A total of 34 quantitative trait loci (QTLs) were detected for 13 traits, and each individual QTL explained 5.7% to 15.9% of the phenotypic variance. Three pleiotropic QTLs involving five root traits were identified; SNP_2_104416607 was associated with lateral root length (LRL), root surface area (RA), root length between 0 and 0.5mm in diameter (RL005), and total root length (TRL); SNP_2_184016997 was associated with RV and RA, and SNP_4_168917747 was associated with LRL, RA and TRL. The expression levels of candidate genes in root QTLs were evaluated by RNA-seq among three long-root lines and three short-root lines. A total of five genes that showed differential expression between the long- and short-root lines were identified as promising candidate genes for the target traits. These QTLs and the potential candidate genes are important source data to understand root development and genetic improvement of root traits in maize.

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