Root Material Research Articles

Transcriptome analysis of sugar beet in response to the pathogenic oomycete Aphanomyces cochlioides

BackgroundAphanomyces root rot is one of the most severe diseases in sugar beet (Beta vulgaris L.), resulting in drastic losses in sugar yield and plant degeneration. The causal agent is the soil-borne pathogen Aphanomyces cochlioides, a phytopathogenic oomycete able to infect sugar beet roots from the seedling stage until harvest. Reliable control measures and fully resistant varieties to prevent the disease on mature roots are currently not available. Furthermore, the quantitative nature of the resistance mechanisms to the root rot disease remain unclear. With the aim to identify key genes involved in plant defense responses against the root rot, we performed a transcriptome analysis of sugar beet interactions with A. cochlioides. The transcriptome responses of two partially resistant and two susceptible sugar beet breeding lines, inoculated with three A. cochlioides isolates with different geographical origins have been investigated in this study.ResultsThe results showed that the transcriptional responses to A. cochlioides infection were mainly genotype-dependent. Comparisons of transcriptome profiles of partially resistant and susceptible breeding lines revealed the presence of differentially expressed genes that play a key role in defense mechanisms during the initial stages of infection. Gene Ontology (GO) categories associated with hydrogen peroxide (H2O2) metabolism, detoxification and cell wall organization were significantly enriched in the differentially expressed gene set from the two partially resistant lines, while photosynthesis-related GO terms were significantly enriched in the two susceptible lines. Unique and overlapping GO categories were over-represented in specific genotype-isolate-time point interactions, indicating that different genotypes respond with common defense strategies as well as specialized responses to different isolates and time points. Transcription factors belonging to the WRKY and ERF families were up-regulated in all genotypes. Furthermore, increased expression of genes encoding for disease resistant proteins have been identified in the two partially resistant genotypes.ConclusionsThis research offers new insights into the transcriptomic events that regulate the sugar beet defense responses to A. cochlioides infection. The findings of this study emphasize the importance of genotype-specific interactions in response to different A. cochlioides isolates. Moreover, the results showed the up-regulation of genes that may play important roles in the defense responses to A. cochlioides which can be used to improve future breeding and to assist in the development of resistant cultivars.

In-vivo Raman microspectroscopy reveals differential nitrate concentration in different developmental zones in Arabidopsis roots

BackgroundNitrate (NO3−) is one of the two major forms of inorganic nitrogen absorbed by plant roots, and the tissue nitrate concentration in roots is considered important for optimizing developmental programs. Technologies to quantify the expression levels of nitrate transporters and assimilating enzymes at the cellular level have improved drastically in the past decade. However, a technological gap remains for detecting nitrate at a high spatial resolution. Using extraction-based methods, it is challenging to reliably estimate nitrate concentration from a small volume of cells (i.e., with high spatial resolution), since targeting a small or specific group of cells is physically difficult. Alternatively, nitrate detection with microelectrodes offers subcellular resolution with high cell specificity, but this method has some limitations on cell accessibility and detection speed. Finally, optical nitrate biosensors have very good (in-vivo) sensitivity (below 1 mM) and cellular-level spatial resolution, but require plant transformation, limiting their applicability. In this work, we apply Raman microspectroscopy for high-dynamic range in-vivo mapping of nitrate in different developmental zones of Arabidopsis thaliana roots in-situ.ResultsAs a proof of concept, we have used Raman microspectroscopy for in-vivo mapping of nitrate content in roots of Arabidopsis seedlings grown on agar media with different nitrate concentrations. Our results revealed that the root nitrate concentration increases gradually from the meristematic zone (~ 250 µm from the root cap) to the maturation zone (~ 3 mm from the root cap) in roots grown under typical growth conditions used for Arabidopsis, a trend that has not been previously reported. This trend was observed for plants grown in agar media with different nitrate concentrations (0.5–10 mM). These results were validated through destructive measurement of nitrate concentration.ConclusionsWe present a methodology based on Raman microspectroscopy for in-vivo label-free mapping of nitrate within small root tissue volumes in Arabidopsis. Measurements are done in-situ without additional sample preparation. Our measurements revealed nitrate concentration changes from lower to higher concentration from tip to mature root tissue. Accumulation of nitrate in the maturation zone tissue shows a saturation behavior. The presented Raman-based approach allows for in-situ non-destructive measurements of Raman-active compounds.

Quantitative Assessment of Apically Extruded Debris During Retreatment Procedures Using Three Nickel-Titanium Rotary Systems: An In Vitro Comparative Study

Objectives: Apical extrusion of debris can affect the success of endodontic treatments, and the specific performance of certain retreatment systems has not been studied yet. Therefore, the aim of this in vitro study was to quantitatively assess the amount of apically extruded debris produced during retreatment procedures using three rotary NiTi retreatment systems in mature non-resorbed straight roots. Methods: Thirty extracted permanent human teeth with single straight roots were selected. The root canals were prepared with the ProTaper Next system up to size 30 and obturated with gutta-percha and AH Plus sealer using the continuous wave of condensation technique. The samples were stored for 30 days and randomized by computer sequence into three retreatment groups (n = 10): (1) ProTaper Universal Retreatment; (2) HyFlex Remover; and (3) VDW.Rotate Retreatment. Apically extruded debris was collected in Eppendorf tubes and weighed with a microbalance (10−5 g) before and after retreatment procedure. As the data were not normally distributed, the Kruskal–Wallis test was applied for comparing data among groups, with an alpha level set at α = 0.05. Dunn’s test was considered for post-hoc analyses, if appropriate. Results: Hyflex Remover was associated with the highest amount of extruded debris (0.85 ± 0.82 mg), followed by VDW.Rotate Retreatment (0.78 ± 0.41 mg) and ProTaper Universal Retreatment (0.62 ± 0.28 mg). However, the differences were not statistically significant (p > 0.05). Conclusions: All the retreatment systems tested were associated with apical extrusion of debris in vitro, with no significant quantitative differences between them, suggesting that clinicians can choose a retreatment system with features appropriate to the specific clinical situation without risk of increasing the amount of apically extruded debris.

Deciphering the molecular logic of WOX5 function in the root stem cell organizer.

Plant and animal stem cells receive signals from their surrounding cells to stay undifferentiated. In the Arabidopsis root, the quiescent center (QC) acts as a stem cell organizer, signaling to the neighboring stem cells. WOX5 is a central transcription factor regulating QC function. However, due to the scarcity of QC cells, WOX5 functions in the QC are largely unexplored at a genomic scale. Here, we unveil the transcriptional and epigenetic landscapes of the QC and the role of WOX5 within them. We find that WOX5 functions both as a transcriptional repressor and activator, affecting histone modifications and chromatin accessibility. Our data expand on known WOX5 functions, such as the regulation of differentiation, cell division, and auxin biosynthesis. We also uncover unexpected WOX5-regulated pathways involved in nitrate transport and the regulation of basal expression levels of genes associated with mature root tissues. These data suggest a role for QC cells as reserve stem cells and primed cells for prospective progenitor fates. Taken together, these findings offer insights into the role of WOX5 at the QC and provide a basis for further analyses to advance our understanding of the nature of plant stem cell organizers.

Root cap cell corpse clearance limits microbial colonization in Arabidopsis thaliana.

Programmed cell death occurring during plant development (dPCD) is a fundamental process integral for plant growth and reproduction. Here, we investigate the connection between developmentally controlled PCD and fungal accommodation in Arabidopsis thaliana roots, focusing on the root cap-specific transcription factor ANAC033/SOMBRERO (SMB) and the senescence-associated nuclease BFN1. Mutations of both dPCD regulators increase colonization by the beneficial fungus Serendipita indica, primarily in the differentiation zone. smb-3 mutants additionally exhibit hypercolonization around the meristematic zone and a delay of S. indica-induced root-growth promotion. This demonstrates that root cap dPCD and rapid post-mortem clearance of cellular corpses represent a physical defense mechanism restricting microbial invasion of the root. Additionally, reporter lines and transcriptional analysis revealed that BFN1 expression is downregulated during S. indica colonization in mature root epidermal cells, suggesting a transcriptional control mechanism that facilitates the accommodation of beneficial microbes in the roots.

Root cap cell corpse clearance limits microbial colonization in Arabidopsis thaliana

Programmed cell death occurring during plant development (dPCD) is a fundamental process integral for plant growth and reproduction. Here, we investigate the connection between developmentally controlled PCD and fungal accommodation in Arabidopsis thaliana roots, focusing on the root cap-specific transcription factor ANAC033/SOMBRERO (SMB) and the senescence-associated nuclease BFN1. Mutations of both dPCD regulators increase colonization by the beneficial fungus Serendipita indica, primarily in the differentiation zone. smb-3 mutants additionally exhibit hypercolonization around the meristematic zone and a delay of S. indica-induced root-growth promotion. This demonstrates that root cap dPCD and rapid post-mortem clearance of cellular corpses represent a physical defense mechanism restricting microbial invasion of the root. Additionally, reporter lines and transcriptional analysis revealed that BFN1 expression is downregulated during S. indica colonization in mature root epidermal cells, suggesting a transcriptional control mechanism that facilitates the accommodation of beneficial microbes in the roots.

Emerging Arabidopsis roots exhibit hypersensitive gravitropism associated with distinctive auxin synthesis and polar transport within the elongation zone

Gravitropism is crucial for plants to secure light, water, and minerals essential for developing seedlings. Despite its importance, the gravitropism of young roots remains largely unexplored. Herein, we reported that the emerging Arabidopsis roots exhibit hypersensitive gravitropism compared to mature roots, growing relatively slowly but bending exceptionally rapidly. This rapid gravibending is characterized by substantial growth inhibition and a distinctive auxin accumulation on the lower side of the elongation zone. Intriguingly, surgical experiments suggest that these auxins predominantly originate from the elongation zone rather than from the shoot or root cap. However, their asymmetrical distribution is heavily modulated by the root cap. Confocal analysis of GFP-tagged TAA1 further confirms that gravitational stimulus induces active auxin biosynthesis in the elongation zone of nascent roots but not in mature roots. Furthermore, mutations in the PIN proteins, especially PIN2, severely impair the rapid gravitropic responses in emerging roots. Interestingly, PIN2 in nascent roots is not confined to the epidermis and cortex but extends to the endodermis, contrasting with its distribution in mature roots. Gravitational stimulation leads to a marked asymmetrical distribution of PIN2 between the upper and lower sides of the roots, which is strongly inhibited by surgical removal of the root cap. These observations indicate that gravitational stimulation triggers active auxin synthesis and PIN protein-mediated lateral transport within the elongation zone of emerging roots, resulting in swift gravitropic responses. These results offer an intriguing enhancement and expansion to the mechanism of root gravitropism.

Differential Exudation Creates Biogeochemically Distinct Microenvironments during Rhizosphere Evolution.

Plant roots and associated microbes release a diverse range of functionally distinct exudates into the surrounding rhizosphere with direct impacts on soil carbon storage, nutrient availability, and contaminant dynamics. Yet mechanistic linkages between root exudation and emergent biogeochemical processes remain challenging to measure nondestructively, in real soil, over time. Here we used a novel combination of in situ microsensors with high-resolution mass spectrometry to measure, nondestructively, changing exudation and associated biogeochemical dynamics along single growing plant roots (Avena sativa). We found that metabolite and dissolved organic carbon (DOC) concentrations as well as microbial growth, redox potential (EH), and pH dynamics vary significantly among bulk soil, root tip, and more mature root zones. Surprisingly, the significant spike of rhizosphere DOC upon root tip emergence did not significantly correlate with any biogeochemical parameters. However, the presence of sugars significantly correlated with declines in EH following the arrival of the root tip, likely due to enhanced microbial oxygen demand. Similarly, the presence of organic acids significantly correlated to declines in pH upon root tip emergence. Overall, our in situ measurements highlight how different exudates released along growing roots create functionally distinct soil microenvironments that evolve over time.

Study on the response of ornamental plant growth on vetiver root mats for bio canvas development

Study on the response of ornamental plant growth on vetiver root mats for bio canvas development

Ginsenoside Profile of White Ginseng Roots and Tinctures

Ginseng roots are medicinal plant raw materials used in pharmaceutical practice in a number of countries due to their pharmacological activities, including tonic. Ginsenosides of ginseng are the main group of biologically active substances responsible for the pharmacological effects of ginseng.One of the modern methods for analyzing ginsenosides is UPLC-MS/MS, which allows one to gain a broad understanding of the ginsenoside profile. The authors used TLC analysis and UPLC-MS/MS to identify and quantify ginsenosides. Of the 18 identified ginsenosides, ginsenosidesRb 1, Rc, Re, Rg1 can be considered as marker ones. These approaches can serve as the basis for the development of regulatory documentation for ginseng and medicines based on it. The total content of ginsenoside in tinctures is higher than in the medicinal plant material of white ginseng roots. Chemical compounds studied in this article: Ginsenoside Rb1 (PubChem CID: 9898279); Ginsenoside Rb2 (PubChem CID: 6917976); Ginsenoside Rb3 (PubChem CID: 12912363); GinsenosideRc (PubChem CID: 12855889); Ginsenoside Rd (PubChem CID: 24721561); Ginsenoside Re (PubChem CID: 119307); Ginsenoside Rf (PubChem CID: 441922); Ginsenoside Rg1 (PubChem CID: 441923); Ginsenoside S-Rg2 (PubChem CID: 12912322); Ginsenoside Ro (PubChem CID: 11815492); Ginsenoside S-Rg3 (PubChem CID: 9918693); Ginsenoside Rg5 (PubChem CID: 11550001); Ginsenoside R-Rh1 (PubChem CID: 21599923); Ginsenoside S-Rh2 (PubChem CID: 91668381); Ginsenoside Rk1 (PubChem CID: 11499198); Ginsenoside Rk3 (PubChem CID: 75412555); Ginsenoside F2 (PubChem CID: 9918692); Ginsenoside F3 (PubChem CID: 46887678); Ginsenoside F4 (PubChem CID: 73717457); Ginsenoside CK (PubChem CID: 9852086).

On some nominations of children in the history of Russian and Chinese languages

The article is devoted to the history of children’s nominations in Russian and Chinese languages. The difference of time range of factual materials used in the article is due to the particularity of the historical development and the fixation of Russian and Chinese languages. The process reveals a serious typological similarity. This is manifested in the possibility of the formation of a large number of nominations from a small number of ancient roots, stability and preservation of the root material, and also in the fact that the semantics of lexemes in both languages can pass through the same stages of their evolution. The meanings of both languages may contain such semantic components as “slave”, “servant, worker”. There are also differences in semantic development between languages. In Russian, the semantics evolve in the direction of age: “child” “young man”. In Chinese, the process can go in the opposite direction-from naming adults to naming children.

Effects of triaxial rolling on the microstructure and installation characteristics of reactor pressure vessel studs

Reactor pressure vessel (RPV) studs are key components of nuclear reactors, and their connection with flange ensures the sealing of the RPV under high-pressure and high-temperature conditions. In the present work, the external threads of the RPV stud were prepared by triaxial rolling, and the texture evolution of the external thread root material of an RPV stud was predicted by finite element analysis coupled with viscoplastic self-consistent simulations. The microstructure of the external thread root material of RPV stud was characterized by scanning electron microscope and electron back-scattered diffraction. The installation characteristics of the turned and rolled parts of the RPV stud were tested by installation and pretightening tests. It was found that the dynamic recrystallization at the external thread root formed ultrafine tempered sorbite grains, high-angle grain boundaries (47%), and strong {111} <110> and {111} <112> textures. In the installation and pretightening test, the residual elongation of rolled parts was reduced by 6% under the same loading pressure. The triaxial rolling process distributed the microstructure of the external thread root of the RPV stud in a gradient manner, resulting in improved stud installation characteristics.

Millennial-aged organic matter preservation in anoxic and sulfidic mangrove soils: Insights from isotopic and molecular analyses

Mangrove forests are known as coastal carbon sinks, but the long-term (millennium-scale) preservation processes of organic matter (OM) in their soils and the role of sulphur in these processes are still not fully understood. These processes are crucial for better estimating the impact of sea-level variations on the carbon dynamics in mangrove forests, which are particularly sensitive to sea-level changes due to their direct hydrological interactions with coastal waters. This study focuses on a soil layer enriched in mangrove-derived OM that accumulated during a stable sea-level period of the Holocene in New Caledonia (South Pacific). Radiocarbon dating situates this enriched layer at approximately 4000 cal BP. The aim of this study is to characterize the enriched OM layer using bulk (Rock-Eval), isotopic (δ13C and δ15N), and molecular (lignin and neutral carbohydrates) analyses. This OM has undergone diagenetic processes such as dehydrogenation, and the loss of components such as the main neutral carbohydrates: glucose, xylose, and galactose. However, some Rock-Eval parameters, the total lignin content, and carbon and nitrogen isotopic ratios are characteristic of well-preserved OM, suggesting differential decomposition/preservation processes. In addition, SEM observations highlighted the presence of pyrite associated to preserved root material. Along with high Sorg/TOC ratio, these results suggest potential processes of OM sulfurization preserving it from decomposition. Prolonged sea-level stability in addition to anoxic and sulfidic soil conditions enhanced OM accumulation and long-term sequestration in mangrove soils.

The Effects of Different Developmental Stages on Bone Regeneration of Periodontal Ligament Stem Cells and Periodontal Ligament Cell Sheets In Vitro and Vivo.

Periodontal ligament stem cells (PDLSCs) have broad applications in tissue engineering and regeneration. However, the function of PDLSCs changes in different microenvironments. This study aimed to explore the effects of different developmental stages on the biological characteristics of PDLSCs. Here, PDLSCs were successfully cultured from the periodontal tissues of various groups, including a group with immature roots, a young group with mature roots, and an aging group with mature roots. By comparing the results of the three experimental groups, we found that the donors with immature roots exhibited the best proliferative ability and osteogenic differentiation, while the aging group demonstrated the worst proliferation. The trend for adipogenic differentiation was the opposite to that for osteogenic differentiation. The cell sheet and in vivo experiments revealed that in the immature root group, the cells produced more extracellular matrix (ECM) and new bone and better absorbed the implant materials. These results indicate that PDLSCs perform various functions at different stages of development. In clinical applications of PDLSCs for periodontal regeneration, donors with incompletely developed roots have stronger biological characteristics.

Biochemical and gene expression profiling of oxalate biosynthesis in cherry tomato (Solanum lycopersicum var. cerasiforme) in Indo-Gangetic Plains of India

The oxalate content was assessed in nine diverse genotypes of cherry tomato in ripened fruit, leaf and root tissues. The maximum oxalate accumulation was found in leaf lamina followed by mature fruit and root tissues among all genotypes where the lowest oxalate content was found in the genotype FB-3-5 and the highest content was recorded in the genotype RSC-4. Examining the leaf and root of nine cherry tomato genotypes at three developmental stages, the investigation into the biosynthesis of oxalates focused on the study of two enzymes, glycolate oxidase (GLO) and ascorbate peroxidase (APX). A positive correlation was observed between oxalate formation and enzyme specific activity of both enzymes. Examining the relative gene expression of oxalate biosynthesizing genes, SlGLO2 and SlAPX7, indicated that the gene SlGLO2 encoded the GLO enzyme and played a crucial role in oxalate biosynthesis in cherry tomatoes. Understanding oxalate biosynthetic pathways and gene expression will aid in developing mechanisms to enhance cherry tomato nutritional quality and improving breeding programmes.

Comparative Evaluation of Different Methods of Activation of Chelating Solution for Smear Layer Removal in the Apical Portion of the Root Canal Using a Scanning Electron Microscopy: An In Vitro Study.

Background The smear layer has an adverse effect on the sealing of root canals during obturation, and it is the main reason for the failure of root canal treatment.Root canal irrigation using a conventional irrigation system is ineffective for smear layer removal, especially from the apical third region, where mostlateral canals are present. For successful endodontic treatment, the smear layer should be removed from the apical third region using an effective irrigation activation system. Aim This study aimed to compare smear layer removal by conventional irrigation, XP Endo Finisher (XPF), endoactivator (EA), passive ultrasonic activation, and root canal brushusing 17% ethylenediaminetetraacetic acid (EDTA) as a chelating solution and 5.25% sodium hypochlorite after chemomechanical preparation, using scanning electron microscopy (SEM). Method A total of 50 extracted human mandibular single canal premolars with mature roots were selected for this study. Samples were decoronated to obtain a standard working length (WL) of 15 mm. Canal patency was achieved using a 10 k file. Samples were sealed with sticky wax to obtain the vapor lock effect. Biomechanical preparation is done till F3. The samples were divided into five groups according to the final irrigation activation protocol: Group 1, control group; group 2, XPF; group 3, EA; group 4, passive ultrasonic irrigation (PUI); and group 5,, root canal brush. Samples were divided into two equal halves longitudinally. Each sample was analyzed for a smear layer under SEM at 2000x magnification. Statistical analysis was done using the one-way Anova "F" test and Tukey's post-hoc test. Results Group 3 showed the least presence of a smear layer, followed by groups 4, 2, 5, and 1. All the groups exhibited highly significant differences between each other (p < 0.001). Group B shows no significant difference with groups C, D, and E. Group C shows no significant difference with groups D and E. Group D shows no significant difference with group E. Conclusion The EA removes the smear layer effectively as compared with other groups. All the irrigation activation system shows the presence of smear layer. No activation systems were able to remove the smear layer completely.

Functional analysis of root-preferential oil palm metallothionein promoter in tobacco.

Root-specific or preferential promoters are essential to genetically modify plants with beneficial root traits. We have characterised the promoter from an oil palm metallothionein gene (EgMT) and performed a serial 5' deletion analysis to identify the region(s) essential for transgenes expression in roots. Stable functional characterisation of tobacco transgenic lines using the T1 generation showed that a deletion construct, designated as RSP-2D (1107bp), directed strong GUS expression at all stages of root development, particularly in mature roots. Other constructs, RSP-2A (2481bp) and RSP-2C (1639bp), drove GUS expression in roots with an intensity lower than RSP-2D. The promoter activity was also detectable in seed pods and immature seeds, albeit at lower levels than CaMV35S. The promoter activity may also be induced by wounding as intact GUS staining was observed at the flower- and leaf-cutting sites of T1 samples carrying either RSP-2C or RSP-2D constructs. The promoter sequence contains cis-acting elements that may act as negative regulators and be responsible for root specificity. The results further indicated that the 5' UTR and ATATT sequences are essential for strong promoter activity. This study highlights the potential of RSP-2D promoter as a tool for modifying root traits through genetic engineering.

Orthodontic extrusion with fixed appliances for treatment of intrusive luxation injuries: A prospective study of 28 permanent maxillary incisors.

Limited evidence exists on the treatment options of tooth repositioning after intrusive luxation. The study aimed to investigate the outcomes and complications of orthodontic extrusion in treating intruded maxillary permanent incisors. A prospective study was conducted involving 28 intruded maxillary permanent incisors treated with orthodontic extrusion, compared with a retrospective control group of 29 teeth that underwent spontaneous re-eruption. The success rate of tooth repositioning, as well as pulp condition, periodontal healing, and root development were assessed and compared. The success rate of orthodontic extrusion was 96.4%, excluding one tooth that was ankylosed before treatment. There were no significant differences in pulp condition between the orthodontic extrusion and control groups for teeth with immature root development. Teeth with mature root development in the orthodontic group, however, showed a significantly higher rate of pulp necrosis (100%, p < .05). Periodontal healing outcomes were similar across both groups, regardless of the maturity of root development. The root length continued increasing during orthodontic extrusion treatment. Orthodontic extrusion treatment could effectively reposition moderately to severely intrusive permanent incisors, without increasing the risk of complications compared with spontaneous re-eruption.

NtZIP5A/B is involved in the regulation of Zn/Cu/Fe/Mn/Cd homeostasis in tobacco.

Plants grow in soils with varying concentrations of microelements, often in the presence of toxic metals e.g. Cd. To cope, they developed molecular mechanisms to regulate metal cross-homeostasis. Understanding underlying complex relationships is key to improving crop productivity. Recent research suggests that the Zn and Cd uptake protein NtZIP5A/B [Zinc-regulated, Iron-regulated transporter-like Proteins (ZIPs)] from tobacco (Nicotiana tabacum L. v. Xanthi) is involved in the regulation of a cross-talk between the two metals. Here, we support this conclusion by showing that RNAi-mediated silencing of NtZIP5A/B resulted in a reduction of Zn accumulation and that this effect was significantly enhanced by the presence of Cd. Our data also point to involvement of NtZIP5B in regulating a cross-talk between Cu, Fe, and Mn. Using yeast growth assays, Cu (but not Fe or Mn) was identified as a substrate for NtZIP5B. Furthermore, GUS-based analysis showed that the tissue-specific activity of the NtZIP5B promoter was different in each of the Zn-/Cu-/Fe-/Mn deficiencies applied with/without Cd. The results indicate that NtZIP5B is involved in maintaining multi-metal homeostasis under conditions of Zn, Cu, Fe, and Mn deficiency, and also in the presence of Cd. It was concluded that the protein regulates the delivery of Zn and Cu specifically to targeted different root cells depending on the Zn/Cu/Fe/Mn status. Importantly, in the presence of Cd, the activity of the NtZIP5B promoter is lost in meristematic cells and increased in mature root cortex cells, which can be considered a manifestation of a defense mechanism against its toxic effects.

Development of inoculation methods for Pythium violae to evaluate resistance of carrot cultivars and efficacy of crop protection products for cavity spot control

AbstractCarrot is a major root vegetable crop grown in many parts of the world. In Europe, cavity spot disease continues to have a major impact on marketable yield. The disease is caused by several Pythium spp., with P. violae the main pathogen in the UK and results in small black lesions on mature carrot roots. The lack of reliable inoculation methods for these Pythium pathogens has, for many years, hampered the identification of new effective crop protection products or carrot varieties that are resistant to the disease. In this research, inoculation methods were developed for P. violae using mycelium or oospores, each of which successfully induced typical cavity spot symptoms in both pot‐ and field‐grown carrots as well as consistent root stunting in the former. These methods were also used to successfully identify carrot cultivars with resistance to cavity spot and confirmed the efficacy of the fungicide metalaxyl‐M against the disease. Results therefore demonstrated that the inoculation methods should be reliable for identifying the efficacy of crop protection products, assessing cavity spot resistance and for further studies investigating the biology and epidemiology of the pathogen.