Tomato Tissues Research Articles

Leaf Extracts from Resistant Wild Tomato Can Be Used to Control Late Blight (Phytophthora infestans) in the Cultivated Tomato.

Late blight disease, caused by Phytophthora infestans (Mont.) de Bary, is one of the most challenging diseases threatening tomato production and other Solanaceae crops. Resistance to late blight is found in certain wild species, but the mechanism behind the resistance is not fully understood. The aim of this study was to examine the metabolic profiles in the leaf tissue of late blight-resistant wild tomato and to investigate if leaf extracts from such genotypes could be used to control late blight in tomato production. We included three recognized late blight-resistant wild tomato accessions of Solanum habrochaites (LA1777, LA2855, and LA1352) and two recognized highly susceptible genotypes, S. lycopersicum (‘Super Strain B’) and S. pimpinellifolium (LA0375). The metabolic profiles were obtained in both inoculated and non-inoculated plants by analyzing leaf extracts using high-resolution gas chromatography-mass spectrometry (GC-MS) with three replicate analyses of each genotype. We focused on volatile organic compounds (VOCs) and identified 31 such compounds from the five genotypes with a retention time ranging from 6.6 to 22.8 min. The resistant genotype LA 1777 produced the highest number of VOCs (22 and 21 in the inoculated and control plants, respectively), whereas the susceptible genotype ‘Super Strain B’ produced the lowest number of VOCs (11 and 13 in the respective plants). Among the VOCs, 14 were detected only in the resistant genotypes, while two were detected only in the susceptible ones. In vitro trials, with the use of a detached leaflet assay and whole-plant approach, were conducted. We revealed promising insights regarding late blight management and showed that metabolic profiling may contribute to a better understanding of the mechanisms behind P. infestans resistance in tomato and its wild relatives.

Tandem Gene Duplication of Dioxygenases Drives the Structural Diversity of Steroidal Glycoalkaloids in the Tomato Clade.

Cultivated tomato (Solanum lycopersicum) contains α-tomatine, a steroidal glycoalkaloid (SGA), which functions as a defense compound to protect against pathogens and herbivores; interestingly, wild species in the tomato clade biosynthesize a variety of SGAs. In cultivated tomato, the metabolic detoxification of α-tomatine during tomato fruit ripening is an important trait that aided in its domestication, and two distinct 2-oxoglutarate-dependent dioxygenases (DOXs), a C-23 hydroxylase of α-tomatine (Sl23DOX) and a C-27 hydroxylase of lycoperoside C (Sl27DOX), are key to this process. There are tandemly duplicated DOX genes on tomato chromosome 1, with high levels of similarity to Sl23DOX. While these DOX genes are rarely expressed in cultivated tomato tissues, the recombinant enzymes of Solyc01g006580 and Solyc01g006610 metabolized α-tomatine to habrochaitoside A and (20R)-20-hydroxytomatine and were therefore named as habrochaitoside A synthase (HAS) and α-tomatine 20-hydroxylase (20DOX), respectively. Furthermore, 20DOX and HAS exist in the genome of wild tomato S. habrochaites accession LA1777, which accumulates habrochaitoside A in its fruits, and their expression patterns were in agreement with the SGA profiles in LA1777. These results indicate that the functional divergence of α-tomatine-metabolizing DOX enzymes results from gene duplication and the neofunctionalization of catalytic activity and gene expression, and this contributes to the structural diversity of SGAs in the tomato clade.

Deciphering Precise Gene Transcriptional Expression Using gwINTACT in Tomato.

Functional gene transcription mainly occurs in the nucleus and has a significant role in plant physiology. The isolation of nuclei tagged in specific cell type (INTACT) technique provides an efficient and stable nucleus purification method to investigate the dynamic changes of nuclear gene transcriptional expression. However, the application of traditional INTACT in plants is still limited to seedlings or root cells because of severe chloroplast pollution. In this study, we proposed a newly designed and simplified INTACT based on mas-enhanced GFP (eGFP)-SlWIP2 (gwINTACT) for nuclear purification in tomato (Solanum lycopersicum) leaves, flowers, and fruits for the first time. The yield of the nucleus purified using gwINTACT from transgenic tomato leaves was doubled compared with using a traditional INTACT procedure, accompanied by more than 95% removal of chloroplasts. Relative gene expression of ethylene-related genes with ethylene treatment was reevaluated in gwINTACT leaves to reveal more different results from the traditional gene expression assay based on total RNA. Therefore, establishing the gwINTACT system in this study facilitates the precise deciphering of the transcriptional status in various tomato tissues, which lays the foundation for the further experimental study of nucleus-related molecular regulation on fruit ripening, such as ChIP-seq and ATAC-seq.

Genome-Wide Analysis of the Protein Phosphatase 2C Genes in Tomato

The plant protein phosphatase 2C (PP2C) plays an irreplaceable role in phytohormone signaling, developmental processes, and manifold stresses. However, information about the PP2C gene family in tomato (Solanum lycopersicum) is relatively restricted. In this study, a genome-wide investigation of the SlPP2C gene family was performed. A total of 92 SlPP2C genes were identified, they were distributed on 11 chromosomes, and all the SlPP2C proteins have the type 2C phosphatase domains. Based on phylogenetic analysis of PP2C genes in Arabidopsis, rice, and tomato, SlPP2C genes were divided into eight groups, designated A–H, which is also supported by the analyses of gene structures and protein motifs. Gene duplication analysis revealed that the duplication of whole genome and chromosome segments was the main cause of SLPP2Cs expansion. A total of 26 cis-elements related to stress, hormones, and development were identified in the 3 kb upstream region of these SlPP2C genes. Expression profile analysis revealed that the SlPP2C genes display diverse expression patterns in various tomato tissues. Furthermore, we investigated the expression patterns of SlPP2C genes in response to Ralstonia solanacearum infection. RNA-seq and qRT-PCR data reveal that nine SlPP2Cs are correlated with R. solanacearum. The above evidence hinted that SlPP2C genes play multiple roles in tomato and may contribute to tomato resistance to bacterial wilt. This study obtained here will give an impetus to the understanding of the potential function of SlPP2Cs and lay a solid foundation for tomato breeding and transgenic resistance to plant pathogens.

Quantitative MRI analysis of structural changes in tomato tissues resulting from dehydration.

A quantitative magnetic resonance imaging (MRI) analysis at 1.5T of the effects of different dehydration regimes on transverse relaxation parameters measured in tomato tissue is presented. Multi-exponential T2 maps have been estimated for the first time, providing access to spatialized microstructural information at voxel scale. The objective was to provide a better understanding of the changes in the multi-exponential transverse relaxation parameters induced by dehydration in tomato tissues and to unravel the effects of microstructure and composition on relaxation parameters. The results led to the hypothesis that the multi-exponential relaxation signal reflects cell compartmentation and tissue heterogeneity, even at the voxel scale. Multi-exponential relaxation times provided information about water loss from specific cell compartments and seem to indicate that the dehydration process mainly affects large cells. By contrast, total signal intensity showed no sensitivity to variations in water content in the range investigated in the present study (between 95% [fresh tissue] and 90% [after dehydration]). The variation in relaxation times resulting from water loss was due to both changes in solute concentration and compartment size. The comparative analysis of the two contrasted tissues in terms of microporosity demonstrated that magnetic susceptibility effects, caused by the presence of air in the placenta tissue, significantly impact the effective relaxation and might be the dominant effect in the variations observed in relaxation times in this tissue.

Cloning and Expression Analysis of Tomato <i>SlSPS1</i> Gene

Sucrose is the main product of plant photosynthesis and participates in many physiological and biochemical reactions of plants. Sucrose phosphate synthase is one of the key rate-limiting enzymes necessary for sucrose to enter various metabolic pathways, and its activity directly reflects the ability of sucrose synthesis in plants. In order to study the mechanism of sucrose synthesis in tomato, this study cloned a sucrose phosphate synthase gene from tomato pulp and named it  SlSPS1 . Through bioinformatics analysis, it was found that its cDNA is 3488bp in length, encoding 1054 amino acids, and there are 3 functional domain. There are 4  SPS  genes in tomato, and their homology is relatively high. In Salicaceae crops, SlSPS1 protein is closely related to potatoes, peppers and eggplants. The results of tissue-specific analysis found that  SlSPS1  was expressed in all tomato tissues, among which the expression was relatively high in the seedling stage and different development stages of the fruit. In order to further study the mechanism of SlSPS1 in tomato growth and sucrose accumulation, an overexpression and knockout vector of  SlSPS1  was constructed and transformed into Micro-Tom to obtain transgenic positive lines. Analysis of the expression level of  SlSPS1  on the obtained transgenic lines showed that the expression levels of the overexpression lines at the seedling stage, fruit green ripe stage and ripening stage were significantly up-regulated compared with the wild type, and the enzyme activity and sucrose content increased. Compared with the wild type, the expression of  SlSPS1  at the seedling stage, green ripe stage and ripening stage of the knockout line was significantly down-regulated, and the enzyme activity and sucrose content were reduced. As for the mechanism of  SlSPS1  in tomato growth and fruit sucrose accumulation, functional verification is needed in the future.

Effect of proteasome inhibitor MG132 on the expression of oxidative metabolism related genes in tomato

Expression analysis of antioxidant related genes may provide key information to develop plants more tolerant to abiotic and biotic stress. For this purpose, in this study, proteosome was inhibited by using MG132 proteosome inhibitor in Lycopersicon esculentum (tomato) tissues with high antioxidant content. We aimed to explain the response of gene isoforms associated with oxidative stress metabolism as a result of proteasome inhibition induced by MG132 in tomato. Gene expression levels of SLGR1, SLPhGPX, SLCAT1, SLFe-SOD, SLGPX, SLCu/Zn-SOD, SLcAPX and SLGST genes which are known to be associated with antioxidant mechanisms, were determined by real-time PCR in tomato. There was no significant change in SLPhGPX, SLCAT1, SL-Fe-SOD and SLcAPX genes in root, stem and leaf tissues. In addition, expression of SLGR1 and SLGST genes in root tissue was increased. In leaf tissue, expression of SLGPX, SLCu/Zn-SOD and SLGST genes increased significantly. There was no significant change in the expression of the genes studied in the shoot tissue. These results obtained from tomato root, stem and leaf tissues by creating proteasome inhibition will help to understand the relationship between antioxidant system and proteasome system in plants.

Detection and Characterization of Viroids via Biological Assays on Herbaceous Hosts.

The characterization of the elusive disease agent of the potato spindle tuber disease, potato spindle tuber viroid (PSTVd), was aided by the ability to obtain large amounts of infected tomato tissue in a simple bioassay where PSTVd was easily mechanically transmissible to an alternate herbaceous host in which it thrived and produced dramatic symptoms in a relatively short period (Diener, Viroids. Handbook of plant virus infections: comparative diagnosis. Elsevier/North-Holland, Amsterdam, pp 913-934, 1981; Diener, Virology 45:411-428, 1971; Raymer and O'Brien, Am Pot J, 39:401-408, 1962). Reactions in the primary, or secondary, herbaceous indicator host can range from asymptomatic to severe depending upon the viroid strain, host species, and environmental conditions and can provide evidence of a viroid infection, but do not permit identification of the viroid in question. Further characterization by molecular hybridization, RT-PCR, and sequence analysis is used to determine the etiology of the disease agent. In this chapter, methods are described for mechanical inoculation of viroids to herbaceous hosts to determine the viroid nature of diseases and the experimental host range of the viroid or to shorten the time required for obtaining relatively large amounts of viroid for subsequent purification and characterization.

Correlation network analysis identified the key interactions of texture profiles with the sensory, physical, and organoleptic properties of cherry tomato cultivars grown under salt stress

Textural properties play an important role in the appreciation and acceptance of fresh tomatoes by consumers. This study aimed to clarify whether the effect of salt stress (50 and 100 mM NaCl) on texture profiles depends on the cultivars and/or tissue types of cherry tomatoes and visually identify the interactions of texture with organoleptic and consumer sensory properties using correlation network analysis. The effect of salt stress on texture profiles differed according to the cherry tomato cultivar, stress intensity, truss, and tissue (outer pericarp, locule, septa). The cohesiveness, gumminess, and chewiness of the outer pericarp and the cohesiveness of the locule were higher in salt-stressed fruit than in control fruit, but the effect was cultivar-dependent. Sensory properties such as overall taste, sweetness, and skin hardness and several organoleptic properties were 1.2–1.7-fold higher in salt-stressed fruit than in control fruit. Although no textural properties interacted with sensory properties in the control fruit network in correlation network analysis, the connectivity of textural properties such as cohesiveness with other traits in salt-stressed fruit increased with increasing salt stress intensity. In the network combining all treatments, the most connected node was cohesiveness, and cohesiveness was the key factor that enhanced the sensory and organoleptic properties of salt-stressed tomatoes, although the effects were cultivar- and tissue-specific. Thus, correlation network analysis provided visual insights into the interactions of textural properties with organoleptic and sensory properties.

Identification, evaluation and selection of a bacterial endophyte able to colonize tomato plants, enhance their growth and control Xanthomonas vesicatoria, the causal agent of the spot disease

Beneficial endophytes are key factors in plant productivity and disease control; therefore, research is ongoing to characterize the potential of endophytes as microbial inoculants to promote plant growth and act as biocontrol agents. In this study, we searched for and identified a set of endophytes occurring naturally in a few important crops. Beneficial endophytes were shown to antagonize several important fungi and bacteria, in particular those affecting tomato (Solanum lycopersicum), including Rhizoctonia solani, Alternaria alternata, Clavibacter michiganensis pv. michiganensis, Ralstonia solanacearum, and Xanthomonas vesicatoria. We characterized the most promising as potential inoculants of tomato, aiming to foster plant growth and control the bacterial spot disease caused by Xanthomonas vesicatoria. Among the selected endophytes, we identified a novel streptomycetes, taxonomically related to Streptomyces avermitilis and a pseudomonad, identified as Pseudomonas granadensis. The beneficial effects of these two bacteria, used as single inoculants or as a combination of both, were seen in a significant increase in root and shoot length (approximately 31% and 34% for the streptomycetes and 18% and 16% for the pseudomonad) and dry root biomass (90% for the streptomycetes and 70% for the pseudomonad). Additionally, both inoculants reduced disease progression and severity following inoculation with X. vesicatoria. There was no significant difference between plants treated with single inoculants and plants treated with both. The penetration and efficient colonization of tomato tissues by a green fluorescent protein-tagged culture of the streptomycetes was observed by confocal microscopy, confirming its endophytic nature.

EXPLORING THE LATEST DEVELOPMENTS IN TOMATO TISSUE CULTURE

The tomato is an important vegetable crop that has grown widely over the past 100 years. The development of in vitro selection techniques could lead to new ways of making plants that can deal with stress. Techniques have been improved to make it possible to develop haploids and somatic hybrids. Also, work has been done to make it possible for tomato cultivars to grow back faster than wild varieties. It's important to consider how stable the genes are in tissue-cultured tomato plants. Many traditional and molecular breeding methods can be used to make cultivars that are resistant to both biotic and abiotic stressors. This essay looks at how tomato tissue culture has changed in several ways. It also talks about the problems that need to be fixed before plant tissue culture techniques can be fully used to make tomatoes grow more quickly and improve their genes. The ways to grow tomato tissue are changing quickly. There is still much work to be done before tissue culture can be used to make hybrid cultivars that can be sold.

Microstructural changes enhance oxygen transport in tomato (Solanum lycopersicum) fruit during maturation and ripening.

Climacteric ripening of tomato fruit is initiated by a characteristic surge of the production rate of ethylene, accompanied by an increase in respiration rate. As both activities consume O2 and produce CO2 , gas concentration gradients develop in the fruit that cause diffusive transport. This may, in turn, affect respiration and ethylene biosynthesis. Gas diffusion in fruit depends on the amount and connectivity of cells and intercellular spaces in 3D. We investigated micromorphological changes in different tomato tissues during development and ripening by visualizing cells and pores based on high-resolution micro-computed tomography, and computed effective O2 diffusivity coefficients based on microstructural features of the tissues. We demonstrated that mesocarp and septa tissues have larger cells but small and more disconnected pores than the placenta and columella, resulting in relatively lower effective O2 diffusivity coefficients. Cell disintegration occurred in the mesocarp and septa during ripening, indicating lysigenous air pore formation and resulting in a gradual increase of the effective O2 diffusivity. The results suggest that hypoxic conditions caused by the increasing size and, hence, diffusion resistance of the growing fruit may induce an increase of tissue porosity that results in a greatly enhanced O2 diffusivity and, thus, helps to alleviate them.

Postharvest spraying of zinc oxide nanoparticles enhances shelf life qualities and zinc concentration of tomato fruits

Plant growth relies on the bioavailability of essential nutrients in the growth environment. Access to mineral nutrients is particularly challenging for crops cultivated in alkaline soil, and in these environments, postharvest application may be effective. Advancements in nanotechnology have provided approaches to improve the essential nutrient content of plants and shelf life of produce. Mineralisation by nanoparticles is a promising postharvest technique that can fortify the essential minerals of plants. This study investigated the role of zinc oxide nanoparticles (ZnO-NPs) as a potential nano-agent to enhance Zn content in tomato (Solanum lycopersicum L.), with ZnO-NPs at 100 mg L–1 applied externally to tomatoes postharvest for 4 weeks. The assimilation of Zn into the tomato tissues was quantified by inductively coupled plasma-mass spectrometry. The main shelf life factors affecting tomato quality, including microbial spoilage, water loss and colour change, were studied. All experimental data were incorporated through the neural networks model to simulate microbial involvement in fruit spoilage. The biological spoilage factor in the shelf life of tomatoes was projected with high accuracy and a relative error of 3%. Application of ZnO-NPs was associated with 47% inhibition of microbial growth on tomatoes, which may enhance the total lycopene content by up to 6%. In addition, the Zn content of tomatoes was significantly enhanced by 17%. The results also shed light on the thermal conductivity of Zn metal, which increased the dehydration of tomatoes and improved colour maturation. This study provides vital information about the beneficial application of ZnO-NPs and their role in mineralisation to enhance the shelf life of tomatoes.

Loss of MAR1 Function is a Marker for Co-Selection of CRISPR-Induced Mutations in Plants.

In this study, we describe the establishment of the knockout marker gene MAR1 for selection of CRISPR/Cas9-edited Arabidopsis seedlings and tomato explants in tissue culture. MAR1 encodes a transporter that is located in mitochondria and chloroplasts and is involved in iron homeostasis. It also opportunistically transports aminoglycoside antibiotics into these organelles and defects of the gene render plants insensitive to those compounds. Here, we show that mutations of MAR1 induced by the CRISPR system confer kanamycin-resistance to Arabidopsis plants and tomato tissues. MAR1 is single-copy in a variety of plant species and the corresponding proteins form a distinct phylogenetic clade allowing easy identification of MAR1 orthologs in different plants. We demonstrate that in multiplexing approaches, where Arabidopsis seedlings were selected via a CRISPR/Cas9-induced kanamycin resistance mediated by MAR1 mutation, a mutation in a second target gene was observed with higher frequency than in a control population only selected for the presence of the transgene. This so called co-selection has not been shown before to occur in plants. The technique can be employed to select for edited plants, which might be particularly useful if editing events are rare.

Effect of biochar produced from sewage sludge on tomato (Solanum lycopersicum L.) growth, soil chemical properties and heavy metal concentrations

The addition of biochar, as shown in the literature, improves significantly the chemical and physical soil properties and plant growth. This study examined the effect of biochar, compost and the combination of them on growth, nutrient and heavy metal concentrations of tomato. Biochar (BC) was produced from sewage sludge by pyrolysis at the temperature of 300 °C. The pot trials were carried out under an open-side greenhouse for a total of four months and under four treatments. The treatments applied were: Untreated soil (Control); soil with 2% w/w biochar (BC–SS); soil with 2% w/w compost (Compost); a mixture of biochar and compost at a 2% w/w level (BC–SS + Compost). The application of biochar exhibited substantial improvement on several soil properties. Total organic carbon (TOC) of soil increased (67%–85%), as did the nitrate nitrogen (55%) and ammonium nitrogen (145%). Additionally, available phosphorus significantly increased (45.5%–54.5%) by the application of biochar with/without compost. Dry weight of the aboveground (stems) and belowground (roots) plant tissues increased as well, although tomato yield was not increased significantly. Concentration of heavy metals and trace elements in tomato tissues was quite low. Traces of chromium (Cr), nickel (Ni), and cobalt (Co) were found only in roots of those treated, while silicon (Si) was present in the roots and stems. Arsenic (As), molybdenum (Mo) and lead (Pb) were detected in all plant tissues, but their concentrations did not exceed the permissible levels established for vegetables. Furthermore, the concentration of arsenic (As) and lead (Pb) in fruits decreased by the addition of the amendments (12%–65%). In conclusion, the addition of sewage sludge biochar improved soil characteristics and plant growth. Yet, prior to its general use, factors such as the type of biomass, soil, rate of application and crop must always be taken into consideration.

Effect of passage through the plant on virulence and endophytic behavioural adaptation in the entomopathogenic fungus Beauveria bassiana

Systemic crop protection using endophytic isolates of entomopathogenic fungi is at the forefront of IPM. Nonetheless, any potential trade-offs between virulence and endophytic behaviour must be elucidated if they are to be effectively used in pest management strategies. Here we investigated endophytic adaptation in an isolate of Beauveria bassiana following successive passage through melon, tomato and cotton tissues. Plants were sprayed with a suspension of B. bassiana endophytic isolate EABb 04/01-Tip to initiate endophytic colonization. Once colonization was established, the fungus was re-isolated from the plant, applied to another plant and re-isolated again; this was repeated to achieve three passages. After each passage, a conidial suspension of each isolate was used in bioassays to evaluate both virulence against 4th instar larvae of the model insect Galleria mellonella and to quantify the extent of endophytic activity in each respective host plant species. When sprayed leaves were inspected for fungal colonization, differences in percentage tissue colonization amongst the plant species were detected after the first re-isolation. Endophytic colonization rates in melon and tomato, which varied from 70 to 100%, were higher than those observed in cotton, which ranged from 40 to 50%; endophytic colonization in cotton increased to 75–100% after the third passage. This improvement in endophytic behaviour in cotton, an apparently suboptimal plant for fungal colonization, suggests an evolutionary adaptation to localized or transient endophytic colonization, while further assays are needed. Meanwhile, when endophytic colonization of non-sprayed leaves distant from the sprayed ones was investigated, endophytic activity was evident in all three crop species suggesting that movement within plants after successive passage increased the extent of endophytic colonization from transient to systemic. The present research highlights the potential for adaptation to endophytic behaviour in crops that are less suitable for endophytic colonization. Furthermore, we demonstrated stability in virulence after multiple passages through host plants. This is a key result for the development of IPM strategies based on endophytic entomopathogenic fungi.

Effect of exogenous silicon and methyl jasmonate on the alleviation of cadmium-induced phytotoxicity in tomato plants.

In the present study, a hydroponic experiment was performed to evaluate the effect of exogenous silicon (Si) and methyl jasmonate (MeJA) on the mitigation of Cd toxicity in tomato seedlings. The results revealed that Cd-stressed plants exhibited growth inhibition, increased lipid peroxidation, and impaired photosynthetic pigment accumulation. However, Si and MeJA applied alone or in combination significantly ameliorated the above-mentioned adverse effects induced by Cd. Among all treatments, Cd+Si+MeJA treatment elevated the dry mass of roots, stems, and leaves by 317.39%, 110.85%, and 119.71%, respectively. The chlorophyll a, chlorophyll b, and carotenoid contents in Cd+Si+MeJA-treated group were dramatically elevated (p < 0.05). Meanwhile, the malondialdehyde content in roots and shoots were reduced by 32.24% and 69.94%, respectively. The Si and MeJA applied separately or in combination also resulted in a prominent decrease of Cd influxes in tomato roots; therefore, a reduction of Cd content in tomato tissues were detected, and the Cd concentration in tomato roots were decreased by 27.19%, 25.18%, and 17.51% in Cd+Si, Cd+MeJA and Cd+Si+MeJA-treated plants, respectively. Moreover, in Cd+Si+MeJA-treated group, the percentage of Cd in cell wall fraction was enhanced while that in organelle fraction was decreased as compared with Cd-stressed plants. Collectively, our findings indicated that Si and MeJA application provide a beneficial role in enhancing Cd tolerance and reducing Cd uptake in tomato plants.

Effects of TiO2 Nanoparticles Incorporation into Cells of Tomato Roots.

In this study, tomato plants were grown in vitro with and without incorporation of TiO2 nanoparticles in Murashige and Skoog (MS) growth medium. The aim of this study was to describe the morphological (area and roundness cell) and mechanical (Young’s Modulus) change in the different tissue of tomato root, epidermis (Ep), parenchyma (Pa), and vascular bundles (Vb), when the whole plant was exposed to TiO2 nanoparticles (TiO2 NPs). light microscopy (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM), wavelength dispersive X-ray fluorescence (WDXRF) techniques were used to identify changes into the root cells when TiO2 NPs were incorporated. TiO2 NPs incorporation produces changes in the area, roundness, and Young’s Modulus of the tomato root. When tomato root is exposed to TiO2 NPs, the Ep and Vb area size decreases from 260.92 µm2 to 160.71 µm2 and, 103.08 µm2 to 52.13 µm2, respectively, compared with the control area, while in Pa tissue the area size was increased considerably from 337.72 mm2 to 892.96 mm2. Cellular roundness was evident in tomato root that was exposed to TiO2 NPs in the Ep (0.49 to 0.67), Pa (0.63 to 0.79), and Vb (0.76 to 0.71) area zones. Young’s Modulus in Pa zone showed a rigid mechanical behavior when tomato root is exposed to TiO2 NPs (0.48 to 4.98 MPa control and TiO2 NPs, respectively). Meanwhile, Ep and Vb were softer than the control sample (13.9 to 1.06 MPa and 6.37 to 4.41 MPa respectively). This means that the Pa zone was stiffer than Ep and Vb when the root is exposed to TiO2 NPs. Furthermore, TiO2 NPs were internalized in the root tissue of tomato, accumulating mainly in the cell wall and intercellular spaces, with a wide distribution throughout the tissue, as seen in TEM.

Bioaccumulation of Heavy Metals in Lycopersicon Esculentum Grown with Tannery Sludge across Some Selected Farmlands in Dawakin Kudu LGA of Kano State, Nigeria

Today, human health has been adversely exposed to many inauspicious threats due to human activities. Evidently, ecotoxicological studies documented that industrial and agricultural wastes tremendously contribute to the contemporary environmental pollution. Meanwhile, the application of tannery sludge as fertilizer has been recently reported in Dawakin Kudu LGA of Kano State, Nigeria and this sludge was suspected to have contained a large quantity of toxic metals. This study was aimed to investigate the presence of toxic metals including Cd, Cr and Pb in the fruits of Tomato (Lycopersicon esculentum) grown with tannery sludge in the selected farms in the study area in order to ascertain their suitability for human consumption. The toxic metals (Cr, Cd and Pb) were found to be incorporated into the tissue of tomato

Short-Term Aging of Pod-Derived Biochar Reduces Soil Cadmium Mobility and Ameliorates Cadmium Toxicity to Soil Enzymes and Tomato.

Contamination of agricultural soil with cadmium (Cd) has become a global concern because of its adverse effects on ecohealth and food safety. Soil amendment with biochar has become one of the phytotechnologies to reduce soil metal phyto-availability and its potential risks along the food chain. Biochar, derived from cocoa pod, was evaluated in soil Cd fractions (exchangeable, reducible, oxidizable, and residual) by modified Commission of the European Communities Bureau of Reference sequential extraction and its efficacy to ameliorate Cd toxicity to soil enzymes and leaf bioactive compounds. A pot experiment was conducted using Cd-spiked soil at 10 mg/kg with tomato (Solanum lycopersicum L.) at a biochar application rate of 1 and 3% (w/w) for 6 wk. The addition of biochar significantly reduced (p < 0.05) the exchangeable, reducible, and residual fractions by at least approximately 23%, with a consequential decrease in Cd root uptake and transport within tomato tissues. The activity of soil enzymes (catalase, dehydrogenase, alkaline phosphatase, and urease) was affected by Cd toxicity. However, with the exception of dehydrogenase, biochar application significantly enhanced the activity of these enzymes, especially at the 3% (w/w) rate. As for the secondary metabolites we studied, Cd toxicity was observed for glutathione, terpenoids, and total phenols. However, the biochar application rate of 1% (w/w) significantly ameliorated the effects of toxicity on the secondary metabolites. In conclusion, biochar demonstrated the potential to act as a soil amendment for Cd immobilization and thereby reduce the bioavailability of Cd in soil, mitigating food security risks. Environ Toxicol Chem 2021;40:3306-3316. © 2020 SETAC.