Advances in understanding plant root hairs in relation to nutrient acquisition and crop root function

2021 ◽  
pp. 127-162
Author(s):  
Timothy S. George ◽  
◽  
Lawrie K. Brown ◽  
A. Glyn Bengough ◽  
◽  
...  
Keyword(s):  
Plant Root ◽  
Root Hairs ◽  
Microbial Interactions ◽  
Flowering Plant ◽  
Agricultural Sustainability ◽  
Root Tip ◽  
Pattern Length ◽  
Crop Root ◽  
Flowering Plant Species ◽  
And Function

Root hairs are found on most terrestrial flowering plant species. They form from epidermal cells at a predetermined distance behind the growing root tip in three main patterns. Their presence, pattern, length, density and function are genetically controlled and numerous genes are expressed solely in root hairs. Their growth and proliferation are attenuated by the environment and root hairs growing in soil are generally shorter and less dense than those in laboratory studies. Root hairs have a number of functions including anchorage, root soil contact and bracing to enable roots to penetrate hard soils. However, their primary function is acquisition of nutrients and water, in particular phosphate. They are the site of transporters, exudation of active compounds and infection point of symbiotic microbial interactions. They have a profound effect on rhizosphere characteristics and are a potentially useful target for breeding crops for future agricultural sustainability.

scholarly journals Conserved and non-conserved triggers of 24-nt reproductive phasiRNAs in eudicots

2021 ◽  
Author(s):  
Suresh Pokhrel ◽  
Kun Huang ◽  
Blake C. Meyers
Keyword(s):  
Small Rnas ◽  
Reproductive Organs ◽  
Flowering Plant ◽  
Small Interfering Rnas ◽  
Expression Of Genes ◽  
Tapetal Cells ◽  
Wild Strawberry ◽  
Flowering Plant Species ◽  
Mother Cells ◽  
And Function

AbstractPlant small RNAs (sRNAs) play important roles in plant growth and development by modulating expression of genes and transposons. In many flowering plant species, male reproductive organs, the anthers, produce abundant phased small interfering RNAs (phasiRNAs). Two classes of reproductive phasiRNAs are generally known, mostly from monocots: pre-meiotic 21-nt phasiRNAs triggered by miR2118, and meiotic 24-nt phasiRNAs triggered by miR2275. Here, we describe conserved and non-conserved triggers of 24-nt phasiRNAs in several eudicots. We found that the abundant 24-nt phasiRNAs in the basal eudicot columbine are produced by the canonical trigger, miR2275, as well as by other non-conserved triggers, miR482/2118 and aco_cand81. These triggering miRNAs are localized in microspore mother cells (MMC) and tapetal cells of meiotic and post-meiotic stage anthers. Furthermore, we identified a new trigger (miR11308) of 24-nt phasiRNAs and an expanded number of 24-PHAS loci in wild strawberry. We validated the presence of miR2275-derived 24-nt phasiRNAs pathway in rose. Finally, we evaluated all the eudicots that have been validated for the presence of 24-nt phasiRNAs as models to study biogenesis and function of 24-nt phasiRNAs and conclude that columbine would be an excellent model because of its extensive number of 24-PHAS loci and its diversity of trigger miRNAs.

The development of crop root architecture and optimization of nutrition acquisition: the case of rice

2021 ◽  
pp. 33-68
Author(s):  
Wei Xuan ◽  
◽  
Yuanming Xie ◽  
Tom Beeckman ◽  
◽  
...  
Keyword(s):  
Root System ◽  
Spatial Configuration ◽  
Plant Root ◽  
Root System Architecture ◽  
Cellular Organization ◽  
Genetic Mechanisms ◽  
Crop Root ◽  
Adverse Environmental Conditions ◽  
Plant Root System ◽  
And Function

Plant root system architecture (RSA), the spatial configuration of a root system in the soil, is critical for water and nutrient acquisition. Rice generates a root system consisting of seminal, lateral, and crown/adventitious roots, whose growth and development are regulated by plant hormones and can be fine-tuned to meet adverse environmental conditions. A broad range of studies have been carried out in the past to decipher the underlying molecular and genetic mechanisms. This chapter summarizes original and more recent findings on genes and molecules identified so far to be involved in rice root development. It also discusses the cellular organization and function of rice roots, as well as the responses of RSA to the availability of water and nutrients.

Histochemical Examination of Invertase Activities in the Growing Tip of the Plant Root

2017 ◽  
Vol 10 (1) ◽  
pp. 35-45
Author(s):  
N.F. Lunkova ◽  
N.A. Burmistrova ◽  
M.S. Krasavina
Keyword(s):  
Plant Root ◽  
Invertase Activity ◽  
Root Tip ◽  
Elongation Zone ◽  
Root Tips ◽  
Phloem Unloading ◽  
Meristem Cell ◽  
Transition To Elongation ◽  
Different Tissues

Background:A growing part of the root is one of the most active sinks for sucrose coming from source leaves through the phloem. In the root, sucrose is unloaded from conducting bundles and is distributed among the surrounding cells. To be involved in the metabolism, sucrose should disintegrate into hexoses by means of degrading enzymes.Aims:The aim of this research was to explore the possibility of the involvement of one such enzymes, invertase, in phloem unloading as well as distribution of its activity in the functionally different tissues of the plant root tips.Method:To estimate the enzyme activities in root tissues, we applied two techniques: the histochemical method using nitro blue tetrazolium. The localization of phloem unloading was studied with carboxyfluorescein, a fluorescent marker for symplastic transport.Results:Invertase activity was not detected in the apical part of the meristem. It appeared only between the basal part of this zone and the beginning of the elongation zone. There is the root phloem unloading in that area. Invertase activity increased with increasing the distance from the root tip and reached the highest values in the region of cell transition to elongation and in the elongation zone. The activities of the enzyme varied in different tissues of the same zone and sometimes in the neighboring cells of the same tissue. Biochemical determination of invertase activity was made in the maize root segments coincident to the zones of meristem, cell elongation and differentiation. The results of both methods of determination of invertase activity were in agreement.Conclusion:It was concluded that phloem unloading correlated with invertase activity, possibly because of the activation of invertase by unloaded sucrose. Invertase is one of the factors involved in the processes preparing the cells for their transition to elongation because the concentration of osmotically active hexoses increases after cleavage of sucrose, that stimulates water entry into the cells, which is necessary for elongation growth.

scholarly journals Remodeling of root morphology by CuO and ZnO nanoparticles: effects on drought tolerance for plants colonized by a beneficial pseudomonad

Botany ◽  
2018 ◽  
Vol 96 (3) ◽  
pp. 175-186 ◽  
Author(s):  
Kwang-Yeol Yang ◽  
Stephanie Doxey ◽  
Joan E. McLean ◽  
David Britt ◽  
Andre Watson ◽  
...  
Keyword(s):  
Calcareous Soils ◽  
Root Hairs ◽  
Triticum Aestivum L ◽  
Metal Stress ◽  
Root Tip ◽  
Zno Nps ◽  
Wheat Seedlings ◽  
Cuo Nps ◽  
Expression Of Genes ◽  
Induced Tolerance

Formulations that include nanoparticles of CuO and ZnO are being considered for agricultural applications as fertilizers because they act as sources of Cu or Zn. Currently, few studies of the effects of these nanoparticles (NPs) consider the three-way interactions of NPs with the plant plus its microbiome. At doses that produced root shortening by both nanoparticles (NPs), CuO NPs induced the proliferation of elongated root hairs close to the root tip, and ZnO NPs increased lateral root formation in wheat seedlings (Triticum aestivum L.). These responses occurred with roots colonized by a beneficial bacterium, Pseudomonas chlororaphis O6 (PcO6), originally isolated from roots of wheat grown under dryland farming in calcareous soils. The PcO6-induced tolerance to drought stress in wheat seedlings was not impaired by the NPs. Rather, growth of the PcO6-colonized plants with NPs resulted in systemic increases in the expression of genes associated with tolerance to water stress. Increased expression in the shoots of other genes related to metal stress was consistent with higher levels of Cu and Zn in PcO6-colonized shoots grown with the NPs. This work demonstrates that plants grown with CuO or ZnO NPs showed cross-protection from different challenges such as metal stress and drought.

scholarly journals Documentation of flora of Rara lake and adjoining areas in mid-western region of Nepal

2013 ◽  
Vol 21 (1) ◽  
pp. 41-47
Author(s):  
BK Basnet
Keyword(s):  
National Park ◽  
Secondary Data ◽  
Flowering Plant ◽  
Western Region ◽  
Ramsar Site ◽  
Secondary Sources ◽  
Data Field ◽  
Adjoining Area ◽  
Faunal Diversity ◽  
Flowering Plant Species

Rara National Park is the smallest national park of the country. It is rich in floral and faunal diversity. Rara is one of the sacred lakes and is listed as a Ramsar site. The aim of the study was to compile the representative flora of Rara lake and to present status of available vegetation. The research used both primary and secondary sources of data. Field visit was conducted in June, 2010 during which more than 300 plant specimens were collected. The secondary data were collected from Rara and adjoining area like Gamgadi. These data were thoroughly analyzed to understand the composition of vegetation. The study revealed the existence of about 224 flowering plant species in the area, under 173 genera and 67 families. Compositae was found to be the largest family (21 species and 17 genera) followed by Rosaceae (19 species and 10 genera). DOI: http://dx.doi.org/10.3126/banko.v21i1.9063 Banko Janakari, Vol. 21, No. 1 2011; 41-47

scholarly journals Fully-automated root image analysis (faRIA)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Narendra Narisetti ◽  
Michael Henke ◽  
Christiane Seiler ◽  
Astrid Junker ◽  
Jörn Ostermann ◽  
...  
Keyword(s):  
Near Infrared ◽  
Climatic Factors ◽  
Plant Root ◽  
Ground Truth ◽  
Parameter Tuning ◽  
Dice Coefficient ◽  
Powerful Analytical Tool ◽  
Manual Interaction ◽  
And Function ◽  
Noisy Background

AbstractHigh-throughput root phenotyping in the soil became an indispensable quantitative tool for the assessment of effects of climatic factors and molecular perturbation on plant root morphology, development and function. To efficiently analyse a large amount of structurally complex soil-root images advanced methods for automated image segmentation are required. Due to often unavoidable overlap between the intensity of fore- and background regions simple thresholding methods are, generally, not suitable for the segmentation of root regions. Higher-level cognitive models such as convolutional neural networks (CNN) provide capabilities for segmenting roots from heterogeneous and noisy background structures, however, they require a representative set of manually segmented (ground truth) images. Here, we present a GUI-based tool for fully automated quantitative analysis of root images using a pre-trained CNN model, which relies on an extension of the U-Net architecture. The developed CNN framework was designed to efficiently segment root structures of different size, shape and optical contrast using low budget hardware systems. The CNN model was trained on a set of 6465 masks derived from 182 manually segmented near-infrared (NIR) maize root images. Our experimental results show that the proposed approach achieves a Dice coefficient of 0.87 and outperforms existing tools (e.g., SegRoot) with Dice coefficient of 0.67 by application not only to NIR but also to other imaging modalities and plant species such as barley and arabidopsis soil-root images from LED-rhizotron and UV imaging systems, respectively. In summary, the developed software framework enables users to efficiently analyse soil-root images in an automated manner (i.e. without manual interaction with data and/or parameter tuning) providing quantitative plant scientists with a powerful analytical tool.

Proteomic Analyses of Soybean Root Tips During Germination

2014 ◽  
Vol 21 (12) ◽  
pp. 1308-1319
Author(s):  
Setsuko Komatsu ◽  
Myeong W. Oh ◽  
Hee Y. Jang ◽  
Soo J. Kwon ◽  
Hye R. Kim ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Proteomic Analysis ◽  
Plant Root ◽  
Root Tip ◽  
Root Tips ◽  
Form Complex ◽  
Molecular Weights ◽  
Soybean Seedlings ◽  
2D Gel ◽  
Proteomic Techniques

Plant root systems form complex networks with the surrounding soil environment and are controlled by both internal and external factors. To better understand the function of root tips of soybean during germination, three proteomic techniques were used to analyze the protein profiles of root tip cells. Proteins were extracted from the root tips of 4-dayold soybean seedlings and analyzed using two-dimensional (2D) gel electrophoresis-based proteomics, SDS-gel based proteomics, and gel-free proteomics techniques. A total of 121, 862, and 341 proteins were identified in root tips using the 2D gel-based, SDS gel-based, and gel-free proteomic techniques, respectively. The proteins identified by 2D gel-based proteomic analysis were predominantly localized in the cytoplasm, whereas nuclear-localized proteins were most commonly identified by the SDS gel-based and gel-free proteomics techniques. Of the 862 proteins identified in the SDS gelbased proteomic analysis, 190 were protein synthesis-related proteins. Furthermore, 24 proteins identified using the 2Dgel based proteomic technique shifted between acidic and basic isoelectric points, and 2 proteins, heat shock protein 70.2 and AAA-type ATPase, displayed two different molecular weights at the same isoelectric point. Taken together, these results suggest that a number of proteins related to protein synthesis and modification are activated in the root tips of soybean seedlings during germination.

scholarly journals ACORBA: Automated workflow to measure Arabidopsis thaliana root tip angle dynamic

2021 ◽  
Author(s):  
Nelson BC Serre ◽  
Matyas Fendrych
Keyword(s):  
Plant Root ◽  
Automated Image Analysis ◽  
Root Tip ◽  
Spatiotemporal Resolution ◽  
Bending Angle ◽  
Root Angle ◽  
Root Gravitropism ◽  
Microscopy Data ◽  
Automated Software ◽  
Over Time

Plants respond to the surrounding environment in countless ways. One of these responses is their ability to sense and orient their root growth toward the gravity vector. Root gravitropism is studied in many laboratories as a hallmark of auxin-related phenotypes. However, manual analysis of images and microscopy data is known to be subjected to human bias. This is particularly the case for manual measurements of root bending as the selection lines to calculate the angle are set subjectively. Therefore, it is essential to develop and use automated or semi-automated image analysis to produce reproducible and unbiased data. Moreover, the increasing usage of vertical-stage microscopy in plant root biology yields gravitropic experiments with an unprecedented spatiotemporal resolution. To this day, there is no available solution to measure root bending angle over time for vertical-stage microscopy. To address these problems, we developed ACORBA (Automatic Calculation Of Root Bending Angles), a fully automated software to measure root bending angle over time from vertical-stage microscope and flatbed scanner images. Moreover, the software can be used semi-automated for camera, mobile phone or stereomicroscope images. ACORBA represents a flexible approach based on both traditional image processing and deep machine learning segmentation to measure root angle progression over time. By its automated nature, the workflow is limiting human interactions and has high reproducibility. ACORBA will support the plant biologist community by reducing time and labor and by producing quality results from various kinds of inputs.

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