scholarly journals Conflicting Auxin-Phosphate Signals Impact on RSL2 Expression and ROS-Homeostasis Linked to Root Hair Growth in Arabidopsis

2018 ◽  
Author(s):  
Silvina Mangano ◽  
Silvina Paola Denita-Juarez ◽  
Eliana Marzol ◽  
Cecilia Borassi ◽  
José M. Estevez
Keyword(s):  
Root Hair ◽  
Hair Growth ◽  
Root Hairs ◽  
Polar Growth ◽  
Complex Signals ◽  
Ros Homeostasis ◽  
Root Hair Growth ◽  
High Auxin

Here, we examined by which mechanism root hairs integrate conflicting growth-signals like the repressive high Pi-level clue and a concomitant high auxin exposure that should promote growth and questioned if these complex signals might activate known molecular players in polar growth.

scholarly journals The molecular link between auxin and ROS-Mediated polar root hair growth

2017 ◽  
Author(s):  
Silvina Mangano ◽  
Silvina Paola Denita-Juarez ◽  
Hee-Seung Choi ◽  
Eliana Marzol ◽  
Youra Hwang ◽  
...  
Keyword(s):  
Cell Size ◽  
Root Hair ◽  
Hair Growth ◽  
Molecular Mechanisms ◽  
Root Hairs ◽  
Oxygen Species ◽  
Polar Growth ◽  
Genes Encoding ◽  
Root Hair Growth ◽  
Original Size

AbstractRoot hair polar growth is endogenously controlled by auxin and sustained by oscillating levels of reactive oxygen species (ROS). These cells extend several hundred-fold their original size toward signals important for plant survival. Although their final cell size is of fundamental importance, the molecular mechanisms that control it remain largely unknown. Here, we show that ROS production is controlled by the transcription factors RSL4, which in turn is transcriptionally regulated by auxin through several Auxin Responsive Factors (ARFs). In this manner, auxin controls ROS-mediated polar growth by activating RSL4, which then upregulates the expression of genes encoding NADPH oxidases (also known as RBOHs, RESPIRATORY BURST OXIDASE HOMOLOG proteins) and Class-III Peroxidases (PER), which catalyse ROS production. Chemical or genetic interference with the ROS balance or peroxidase activity affect root hair final cell size. Overall, our findings establish a molecular link between auxin regulated ARFs-RSL4 and ROS-mediated polar root hair growth.Significance StatementTip-growing root hairs are excellent model systems to decipher the molecular mechanism underlying reactive oxygen species (ROS)-mediated cell elongation. Root hairs are able to expand in response to external signals, increasing several hundred-fold their original size, which is important for survival of the plant. Although their final cell size is of fundamental importance, the molecular mechanisms that control it remain largely unknown. In this study, we propose a molecular mechanism that links the auxin-Auxin Response Factors (ARFs) module to activation of RSL4, which directly targets genes encoding ROS-producing enzymes, such as NADPH oxidases (or RBOHs) and secreted type-III peroxidases (PERs). Activation of these genes impacts apoplastic ROS homeostasis, thereby stimulating root hair cell elongation.

scholarly journals High Auxin and High Phosphate Impact on RSL2 Expression and ROS-Homeostasis Linked to Root Hair Growth in Arabidopsis thaliana

2018 ◽  
Vol 9 ◽  
Author(s):  
Silvina Mangano ◽  
Silvina P. Denita-Juarez ◽  
Eliana Marzol ◽  
Cecilia Borassi ◽  
José M. Estevez
Keyword(s):  
Arabidopsis Thaliana ◽  
Root Hair ◽  
Hair Growth ◽  
Ros Homeostasis ◽  
Root Hair Growth ◽  
High Auxin ◽  
High Phosphate

scholarly journals The TOR–Auxin Connection Upstream of Root Hair Growth

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 150 ◽  
Author(s):  
Katarzyna Retzer ◽  
Wolfram Weckwerth
Keyword(s):  
Cell Fate ◽  
Root Hair ◽  
Hair Growth ◽  
Environmental Changes ◽  
Growth Control ◽  
Root Hairs ◽  
Signaling Cascades ◽  
Continuous Growth ◽  
Root Hair Cell ◽  
Root Hair Growth

Plant growth and productivity are orchestrated by a network of signaling cascades involved in balancing responses to perceived environmental changes with resource availability. Vascular plants are divided into the shoot, an aboveground organ where sugar is synthesized, and the underground located root. Continuous growth requires the generation of energy in the form of carbohydrates in the leaves upon photosynthesis and uptake of nutrients and water through root hairs. Root hair outgrowth depends on the overall condition of the plant and its energy level must be high enough to maintain root growth. TARGET OF RAPAMYCIN (TOR)-mediated signaling cascades serve as a hub to evaluate which resources are needed to respond to external stimuli and which are available to maintain proper plant adaptation. Root hair growth further requires appropriate distribution of the phytohormone auxin, which primes root hair cell fate and triggers root hair elongation. Auxin is transported in an active, directed manner by a plasma membrane located carrier. The auxin efflux carrier PIN-FORMED 2 is necessary to transport auxin to root hair cells, followed by subcellular rearrangements involved in root hair outgrowth. This review presents an overview of events upstream and downstream of PIN2 action, which are involved in root hair growth control.

scholarly journals Phosphorus-induced change in root hair growth is associated with IAA accumulation in walnut

2021 ◽  
Vol 49 (4) ◽  
pp. 12504
Author(s):  
Yongjie XU ◽  
Chunyong XU ◽  
Dejian ZHANG ◽  
Xianzhen DENG
Keyword(s):  
Root Hair ◽  
Hair Growth ◽  
Juglans Regia ◽  
Root Hairs ◽  
Forest Tree ◽  
Root Surface ◽  
Nutrient Contents ◽  
Phosphorus Stress ◽  
Low Phosphorus ◽  
Root Hair Growth

Walnut, an important non-wood product forest tree, has free root hairs in orchards. Root hairs are specialized cells originating from the root epidermis that are regulated by plant hormones, such as auxins. This study was conducted to evaluate the effect and mechanism of phosphorus stress on root hair growth of walnut (Juglans regia L.) seedings by auxin (IAA) biosynthesis and transport. Both low phosphorus (LP) and no phosphorus stresses (NP) heavily decreased plant height, leaf number, total root length, root surface, shoot and root biomass, and root nutrient contents. The LP treatment significantly increased root hair growth, accompanied with up-regulation of the positive regulation root hair growth gene JrCPC and down-regulation of the negative regulation root hair growth gene JrTTG1, while the NP treatment had opposite effects. The root IAA level, IAAO activities, IAA transport genes (JrAUX1, JrLAX1, and JrPIN1), and the biosynthesis genes (JrTAA1 and JrTAR1) were increased by the LP treatment, while the NP treatment decreased all of them. Interestingly, the auxin biosynthesis gene CsYUCCA1 was not affected, which suggested that P mainly affects root hair growth of walnut by regulating auxin transport, and then affects root nutrient absorption and plant growth.

scholarly journals Ethylene promotes root hair growth through coordinated EIN3/EIL1 and RHD6/RSL1 activity in Arabidopsis

2017 ◽  
Vol 114 (52) ◽  
pp. 13834-13839 ◽  
Author(s):  
Ying Feng ◽  
Ping Xu ◽  
Bosheng Li ◽  
Pengpeng Li ◽  
Xing Wen ◽  
...  
Keyword(s):  
Root Hair ◽  
Hair Growth ◽  
Root Hairs ◽  
Environmental Signals ◽  
Environmental Interactions ◽  
Two Factors ◽  
Root Hair Growth ◽  
Transcriptional Complex ◽  
Root Hair Initiation ◽  
Molecular Framework

Root hairs are an extensive structure of root epidermal cells and are critical for nutrient acquisition, soil anchorage, and environmental interactions in sessile plants. The phytohormone ethylene (ET) promotes root hair growth and also mediates the effects of different signals that stimulate hair cell development. However, the molecular basis of ET-induced root hair growth remains poorly understood. Here, we show that ET-activated transcription factor ETHYLENE-INSENSITIVE 3 (EIN3) physically interacts with ROOT HAIR DEFECTIVE 6 (RHD6), a well-documented positive regulator of hair cells, and that the two factors directly coactivate the hair length-determining gene RHD6-LIKE 4 (RSL4) to promote root hair elongation. Transcriptome analysis further revealed the parallel roles of the regulator pairs EIN3/EIL1 (EIN3-LIKE 1) and RHD6/RSL1 (RHD6-LIKE 1). EIN3/EIL1 and RHD6/RSL1 coordinately enhance root hair initiation by selectively regulating a subset of core root hair genes. Thus, our work reveals a key transcriptional complex consisting of EIN3/EIL1 and RHD6/RSL1 in the control of root hair initiation and elongation, and provides a molecular framework for the integration of environmental signals and intrinsic regulators in modulating plant organ development.

scholarly journals The abnormal structure induced in nodules on lucerne ( Medicago sativa L.) by the supply of sodium nitrate to the host plant

1936 ◽  
Vol 120 (817) ◽  
pp. 240-252 ◽  
Keyword(s):  
Host Plant ◽  
Sodium Nitrate ◽  
Root Hair ◽  
Hair Growth ◽  
Inhibitory Action ◽  
Root Hairs ◽  
Nitrogenous Compounds ◽  
Root Hair Growth ◽  
Nodule Growth ◽  
Irregular Growth

It was shown in a recent paper (Thornton and Nicol, 1936) that the application of sodium nitrate to inoculated lucerne grown in sand, produced two effects upon the development of nodules. Firstly, the number of nodules was reduced and, secondly, their mean size was diminished. Both these effects increased with the nitrate dose, but, with weak doses of nitrate, it was the reduction in mean nodule size that principally affected the total mass of bacterial tissue carried by the host plant. Nevertheless, the action of nitrates in reducing the number of nodules, that is, their influence upon root infection, has occupied the attention of many workers, whereas but few have studied the growth of nodules on roots supplied with nitrates. The action of nitrate in diminishing root-hair infection by the nodule organism was recently investigated by one of us (Thornton, 1936). Infection is preceded by an increased and irregular growth of the root-hairs which is induced by secretions of the bacteria. Without this irregular growth the root-hairs remain uninfected. Nitrate inhibits this action of the bacterial secretions in stimulating irregular root-hair growth, and so checks infection. The action of nitrate upon legume root-hairs is thus superficially analogous to its action upon the already formed nodule, where it inhibits or checks the growth, which is normally stimulated by the presence of the contained bacteria. Only by a close study of the detailed effects of nitrate upon nodule growth could the significance of this analogy be disclosed. The action of nitrate in reducing the irregular growth of root-hairs exposed to the sterile secretions of nodule bacteria, can to some extent be counteracted by the simultaneous supply of dextrose to the roots (Thornton, 1936). This suggests that the inhibitory action of the nitrate upon root-hair growth is an indirect one, due to the building up of protein within the plant resulting in a shortage of carbohydrate supply to the root-hairs. One might thus expect, by analogy, that the reduction of nodule growth in a nitrate-fed plant could also be explained as being due to carbohydrate deficiency. Fred and Wilson (1934) indeed found that the size of individual nodules on soybeans was reduced by sodium nitrate manuring, but that this effect could largely be overcome by enriching the carbon dioxide supply to the leaves. This hypothesis would be supported if the structure of nodules on nitrate-manured plants showed evidences of carbohydrate shortage. A somewhat different explanation of the nitrate effect was put forward by Giöbel (1926) who supposed that the concentration of nitrate in the tissues of the host plant checked the removal of the products of nitrogen fixation, which thus accumulated in the nodule until they become toxic to the bacteria. On this hypothesis, nodules on plants given nitrate should perhaps show evidence of the accumulation of nitrogenous compounds, such as protein, in the nodule cells. It seemed, therefore, that a comparison of the detailed structure of nodules on plants grown with and without nitrate might supply facts, by which the above hypotheses could be tested, or which would suggest some other explanation of the inhibitory action of nitrate.

scholarly journals GTL1 is required for a robust root hair growth response to avoid nutrient overloading

2021 ◽  
Author(s):  
Michitaro Shibata ◽  
David S Favero ◽  
Ryu Takebayashi ◽  
Ayako Kawamura ◽  
Bart Rymen ◽  
...  
Keyword(s):  
Nutrient Availability ◽  
Root Hair ◽  
Hair Growth ◽  
Root Hairs ◽  
The Face ◽  
Hand Defects ◽  
Positive Regulators ◽  
Root Hair Formation ◽  
Root Hair Growth ◽  
Hair Formation

Root hair growth is tuned in response to the environment surrounding plants. While most of previous studies focused on the enhancement of root hair growth during nutrient starvation, few studies investigated the root hair response in the presence of excess nutrients. We report that the post-embryonic growth of wild-type Arabidopsis plants is strongly suppressed with increasing nutrient availability, particularly in the case of root hair growth. We further used gene expression profiling to analyze how excess nutrient availability affects root hair growth, and found that RHD6 subfamily genes, which are positive regulators of root hair growth, are down-regulated in this condition. On the other hand, defects in GTL1 and DF1, which are negative regulators of root hair growth, cause frail and swollen root hairs to form when excess nutrients are supplied. Additionally, we observed that the RHD6 subfamily genes are mis-expressed in gtl1-1 df1-1. Furthermore, overexpression of RSL4, an RHD6 subfamily gene, induces swollen root hairs in the face of a nutrient overload, while mutation of RSL4 in gtl1-1 df1-1 restore root hair swelling phenotype. In conclusion, our data suggest that GTL1 and DF1 prevent unnecessary root hair formation by repressing RSL4 under excess nutrient conditions.

scholarly journals Impacts of iron on phosphate starvation-induced root hair growth in Arabidopsis

2021 ◽  
Author(s):  
Caiwen Xue ◽  
Wenfeng Li ◽  
Ren Fang Shen ◽  
Ping Lan
Keyword(s):  
Root Hair ◽  
Hair Growth ◽  
Vesicle Trafficking ◽  
Primary Root ◽  
Root Hairs ◽  
Brefeldin A ◽  
Phosphate Starvation ◽  
Auxin Distribution ◽  
Root Hair Growth ◽  
Underlying Mechanisms

Phosphate is essential for plant growth and development. Root architecture alternations induced by phosphate starvation (-Pi), including primary root and lateral root growth, are mediated by iron (Fe). However, whether and how Fe participates in the -Pi-induced root hair growth (RHG) remains unclear. Here, with morphological, proteomic, and pharmacological analysis, we investigate the impacts of Fe on RHG under -Pi and the underlying mechanisms. We found that -Pi-induced RHG was affected by the local Fe availability. Reduced sensitivity to Fe was found in aux1-7, arf10arf16, and phr1 under -Pi, indicating auxin and phosphate starvation-induced responses were required for the Fe-triggered RHG under -Pi. Fe availability was then found to affect the auxin distribution and expression of phosphate starvation-responsive (PSR) genes. Proteomic analysis indicated vesicle trafficking was affected by Fe under -Pi. With the application of brefeldin A, we found the vesicle trafficking was affected by Fe, and root hairs displayed reduced sensitivity to Fe, indicating the vesicle trafficking is critical for Fe-triggered RHG under -Pi. Our data suggested that Fe is involved in RHG under -Pi by integrating the vesicle trafficking, auxin distribution, and PSR. It further enriches the understanding of the interplay between phosphate and iron on RHG.

scholarly journals NAC transcription factor RD26 is a regulator of root hair morphogenic plasticity

2021 ◽  
Author(s):  
Iman Kamranfar ◽  
Salma Balazadeh ◽  
Bernd Mueller-Roeber
Keyword(s):  
Cell Wall ◽  
Transcription Factor ◽  
Drought Stress ◽  
Root Hair ◽  
Regulatory Network ◽  
Hair Growth ◽  
Root Hairs ◽  
Nac Transcription Factor ◽  
Numerous Cell ◽  
Root Hair Growth

AbstractRoot hairs are outgrowths of epidermal cells central for water and nutrient acquisition. Root hair growth is plastically modified by environmental cues. A frequent response to water limitation is active shortening of root hairs, involving largely unknown molecular mechanisms. A root hair-specific cis-regulatory element (RHE) integrates developmental cues with downstream signalling of root hair morphogenesis. Here, we demonstrate NAC transcription factor RD26 to be a key expressional regulator of this drought stress-triggered developmental response in Arabidopsis thaliana. RD26 directly represses RSL4 and RSL1, two master transcription regulators of root hair morphogenesis, by binding RHE. RD26 further represses core cell wall modification genes including expansins (EXPA7, EXPA18), hydroxyproline-rich glycoproteins (LRX1), xyloglucan endotransglucosylases/hydrolases (XTH12, 13, 14, 26), class III peroxidases (PRX44) and plasma membrane H+-ATPase (AHA7) through RHE. Of note, several RD26-repressed genes are activated by RSL4. Thus, by repressing RSL4 and numerous cell wall-related genes, RD26 governs a robust gene regulatory network for restricting root hair growth under drought. A similar regulatory network exists in tomato, indicating evolutionary conservation across species.Significance statementIn plants, root hairs play a vital role for water and nutrient acquisition, soil anchorage, and microbial interactions. During drought stress, root hair growth is suppressed as an adaptive strategy to save cellular energy. We identified NAC transcription factor RD26 as a key regulator of this developmental plasticity in the model plant Arabidopsis thaliana. RD26 directly and negatively controls the transcriptional activity of key root hair developmental genes, RSL1 and RSL4. Furthermore, RD26 suppresses the expression of several functional genes underlying root hair development including numerous cell wall-related genes. RD26 thus governs a robust gene regulatory network underlying the developmental response to drought stress. A similar regulatory network exists in tomato indicating evolutionary conservation of this mechanism across species.

scholarly journals Hormonal regulation of root hair growth and responses to the environment in Arabidopsis

2020 ◽  
Vol 71 (8) ◽  
pp. 2412-2427 ◽  
Author(s):  
Kris Vissenberg ◽  
Naomi Claeijs ◽  
Daria Balcerowicz ◽  
Sébastjen Schoenaers
Keyword(s):  
Root Hair ◽  
Hormonal Regulation ◽  
Hair Growth ◽  
Root Hairs ◽  
Feedback Loops ◽  
Root Hair Development ◽  
Heterogeneous Soil ◽  
Root Hair Growth ◽  
Hair Development ◽  
Signalling Cascade

Abstract The main functions of plant roots are water and nutrient uptake, soil anchorage, and interaction with soil-living biota. Root hairs, single cell tubular extensions of root epidermal cells, facilitate or enhance these functions by drastically enlarging the absorptive surface. Root hair development is constantly adapted to changes in the root’s surroundings, allowing for optimization of root functionality in heterogeneous soil environments. The underlying molecular pathway is the result of a complex interplay between position-dependent signalling and feedback loops. Phytohormone signalling interconnects this root hair signalling cascade with biotic and abiotic changes in the rhizosphere, enabling dynamic hormone-driven changes in root hair growth, density, length, and morphology. This review critically discusses the influence of the major plant hormones on root hair development, and how changes in rhizosphere properties impact on the latter.

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