Fruit Tissue Research Articles

Isolation, Identification, Phytochemical Characterization, and In Vitro Anti-Inflammatory Property of an Endophytic Trametes Versicolor CL-1 Isolated from Rosa Roxburghii.

This study explores the anti-inflammatory potential of an endophytic fungus, Trametes versicolor CL-1, isolated from the fruit tissues of Rosa roxburghii. Morphological and molecular analyses confirmed the identity of CL-1. An ethyl acetate extract (CL-E) from its fermentation broth was subjected to UPLC-HRMS and GNPS molecular networking. The analysis revealed a diverse array of secondary metabolites, including 11 terpenes, 7 flavonoids, 10 cinnamic acid derivatives, 6 oligopeptides, and 9 fatty acids, as verified by LC-MS/MS. Notably, CL-E exhibited significant in vitro anti-inflammatory activity in RAW264.7 cells. Furthermore, molecular docking studies predicted favorable binding interactions of key compounds 1 within CL-E with the NLRP3 inflammasome (PDB ID: 6NPY). These findings suggest T. versicolor CL-1 as a promising source of natural anti-inflammatory agents and unveil R. roxburghii as a potential reservoir for discovering novel bioactive metabolites.

Multiscale Modeling and Simulation of Falling Collision Damage Sensitivity of Kiwifruit.

Falling damage is the most common form of damage sustained by kiwifruit during the process of picking and post-processing, and it is difficult to conduct a quantitative analysis of this phenomenon through traditional experimental methods. In order to deeply understand the sensitivity of kiwifruit to falling collision damage, the finite element numerical simulation method was used to evaluate and predict the sensitivity of kiwifruit to falling collision damage during harvesting. First, we obtained the appearance characteristics of kiwifruit through reverse engineering technology and determined the geometric and mechanical property parameters of kiwifruit through physical mechanics experiments. Then, according to the characteristics of fruit tissue structure, a multiscale finite element model, including the skin, pulp, and core, was constructed to simulate the effects of different falling heights, collision angles, and contact surface materials on fruit damage, and the accuracy of the model was verified through falling experiments. Finally, based on the simulation results, the Box-Behnken design was employed within the response surface methodology to establish a sensitivity prediction model for the drop damage sensitivity of kiwifruit across different contact materials. The results showed that the maximum relative error between the speed change obtained using finite element simulation and the speed obtained by the high-speed camera was 5.19%. The model showed high rationality in energy distribution, with the maximum value of hourglass energy not exceeding 0.08% of the internal energy. On the contact surface material with a large elastic modulus, a higher falling height and larger collision angle will significantly increase the risk of fruit bruise. When the contact surface material was a steel plate, the falling height was 1 m, and the collision angle was 90°; the maximum bruise sensitivity of kiwifruit reached 6716.07 mm3 J-1. However, when the contact surface material was neoprene, the falling height was 0.25 m, and the collision angle was 0°, the damage sensitivity was the lowest, at 1570.59 mm3 J-1. The multiscale finite element model of kiwifruit falling collision constructed in this study can accurately predict the damage of kiwifruit during falling collision and provide an effective tool for the quantitative analysis of kiwifruit falling collision damage. At the same time, this study can also provide guidance for the design and optimization of the loss reduction method of the harvesting mechanism, which has important theoretical significance and practical value.

The CaABCG14 transporter gene regulates the capsaicin accumulation in Pepper septum

Capsaicin (CAP), a crucial compound found in chili peppers, not only contributes to their spicy flavor but also possesses several industrial applications. CAP biosynthetic pathway is well known, while its transport mechanism remains elusive. Herein, we performed a comparative transcriptome analysis conducted on pepper fruit tissues at three different stages of development. Four important CAP transporter genes, including one MATE and three ABCs, were identified by differential expression and WGCNA analysis. Specifically, the expression patterns of three ABC genes were assessed in the septum of fruits from nine distinct genotypes of peppers with high capsaicin levels. Interestingly, CaABCG14 was associated with variations in CAP concentration and co-expressed with genes involved in CAP biosynthesis. Transient expression assay revealed that CaABCG14 is localized to the membrane and nucleus. Silencing of CaABCG14 resulted in a notable reduction in the levels of CAP contents and the expression of its biosynthetic genes in the septum of pepper. The overexpression of CaABCG14 greatly intensified the cytotoxic effects of CAP on the yeast cells. Taken together, we for the first time identified a new transporter gene CaABCG14, regulating the CAP accumulation in pepper septum. These findings offer a fresh molecular theoretical framework for CAP transport and accumulation.

Comparative transcriptome analysis of cucumber fruit tissues reveals novel regulatory genes in ascorbic acid biosynthesis.

Ascorbic acid (AsA) is one of the most abundant natural antioxidants, and it is an important indicator of the nutritional value of cucumber fruit. The aim of this study was to elucidate the regulatory mechanism affecting AsA metabolism in cucumber fruit. In this study, the AsA content in the fruit of two cucumber cultivars (H28 and H105) was significantly higher in the exocarp and endocarp than in the mesocarp. To clarify the regulation of AsA in cucumber fruit, the transcriptomes of three fruit tissues (i.e., the exocarp, mesocarp, and endocarp) of two cucumber cultivars (H28 and H105) were sequenced. Transcriptomic profiling combined with transcription factors (TFs) and correlation analysis were performed to reveal that three genes, including CsaV3_5G014110 (phosphomannomutase, PMM), CsaV3_2G004170 (GDP-mannose-3', 5'-epimerase, GME) and CsaV3_5G006680 (dehydroascorbate reductase, DHAR), were expressed at higher level in the exocarp and endocarp than in the mesocarp. In both two cultivars, CsaV3_4G028360 (ethylene-responsive transcription factor, ERF) was negatively correlated with PMM and GME, and positively correlated with DHAR. CsaV3_6G042110 (ethylene-responsive transcription factor, ERF) was positively correlated with PMM and GME, and negatively correlated with DHAR. CsaV3_6G032360 (mitogen-activated protein kinase, MAPK) as positively correlated with PMM, GME and DHAR. These six genes are considered the key candidate genes for further research. This study provides insight for further study on the regulation of AsA biosynthesis in cucumber fruit and provide potential candidate genes for future genetic improvement of cucumber germplasm with enhanced AsA accumulation.

Electrical Impedance Spectroscopy: A Tool for Determining the Harvesting Time of Olive Fruit

The harvesting time of olive (Olea europaea L.) fruit, which significantly affects the characteristics of virgin olive oil, is mainly determined empirically based on the fruit’s skin color. Developing objective methods such as electrical impedance spectroscopy (EIS) for assessing ripeness is essential. This study aimed to explore the potential of EIS as a rapid and objective technique for detecting the harvesting time of olives. Olive fruits from two varieties, ‘Picholine’ and ‘Buža momjanska’, were harvested in two periods and sorted into four color groups. EIS was applied to each color group to establish a relationship between fruit color and electrochemical properties. The distance of the coordinate at the top of the circular arc of the Cole–Cole plot from the origin (LTO) indicated tissue degradation. The LTO values varied depending on the olive variety, fruit color, and harvest date. The LTO values decreased from green to black fruits in both varieties, indicating textural changes in the olive fruit tissue. This study contributes to the knowledge and understanding of the electrical properties of olive fruit tissue during ripening. EIS shows potential as an innovative tool for determining the harvesting time of olives and for ‘in-field’ olive ripeness assessment.

Global transcription and metabolic profiles of five tissues in pepper fruits

Studying the regulatory mechanisms in different tissues of pepper is crucial for understanding organ formation, growth, and development. However, relevant studies are far from sufficient. In the current study, the stipe, calyx, pericarp, placenta, and seed of ripe pepper were sampled, and metabolites were determined by the untargeted metabolomics method. Transcriptome sequencing was performed by Illumina NovaSeq 6000, and then a high-throughput data set was built. The results showed that a total of 4879 annotated metabolites were detected in 15 samples of the five tissues under positive and negative ion mode. A total of 110.66 Gb of clean data was obtained by transcriptome sequencing, the clean data of each sample reached 6.21 Gb, and a total of 35 336 annotated expression genes were obtained. Furthermore, validate the accuracy of the data by combining principal component analysis and other methods. In summary, this study provides valuable information for the genetic improvement and breeding of peppers, and it holds potential application value, particularly in enhancing the quality and nutritional value of pepper fruits.

Macroscopic and microscopic investigations of determining elasto-mechanical properties of limequat fruit.

Given the paramount importance of agricultural products in global health and food security, and the increasing consumer demand, understanding the mechanical behavior of these materials under various conditions is necessary yet challenging. Due to their heterogeneous and non-uniform nature, determining their mechanical behavior is complex. This study employs atomic force microscopy (AFM) to determine the modulus of elasticity of limequat fruit at the microscopic scale and compares it with macroscopic methods. The analyses revealed a statistically significant difference (at the 1% level) in the mechanical behavior determined at the macroscopic scale. The highest modulus of elasticity, 0.752 MPa, was observed using Hertz's theory under complete placement between two parallel planes. The lowest, 0.059 MPa, was noted when a spherical probe compressed a rectangular sample. The average modulus of elasticity of the limequat peel was 2.007 MPa. At the microscopic scale, the modulus of elasticity of the fruit tissue ranged from 0.370 to 0.365 MPa, and for the peel, it was 0.246 MPa. RESEARCH HIGHLIGHTS: Working principles of this innovative technique were elaborated. The AFM technique used provide elasto-mechanical properties determination of cell walls of single living cells extracted from biological materials on the nanoscale. By combining AFM topographical image and nano-indentation of living fruit cells it will be possible to investigate cells' elasto-mechanical properties. Atomic force microscopy holds great potential for monitoring fruit mechanical properties of biological materials.

Comparative analysis of transcriptome in oil biosynthesis between seeds and non-seed tissues of Symplocos paniculata fruit.

The Symplocos paniculata, a woody oil plant, has garnered attention for its oil-rich fruit, which exhibits potential for both oil production and ecological restoration endeavors, thereby presenting substantial developmental value. However, the comprehension of the distinctive oil biosynthesis and deposition strategies within the fruit's various compartments, coupled with the tissue-specific biosynthetic pathways yielding optimal fatty acid profiles, remains in its infancy. This investigation was designed to delineate the tissue specificity of oil biosynthetic disparities and to elucidate the molecular underpinnings within the fruit mesocarp and seeds of S. paniculata, employing lipidomic and transcriptomic analyses. The results revealed that oil biosynthesis within the fruit mesocarp commences approximately 40 days prior to that within the seeds, with a concomitant higher lipid content observed in the mesocarp, reaching 43% as opposed to 30% in the seeds. The fruit mesocarp was found to be enriched with palmitic acid (C16:0) and exhibited a harmonious ratio of saturated, monounsaturated, to polyunsaturated fatty acids (SFA: MUFA: PUFA=1:1:1), in stark contrast to the seed oil, which is predominantly composed of unsaturated fatty acids, accounting for 90% of its total FA content. Microstructural assessments have unveiled divergent oil deposition modalities; the fruit mesocarp oils are predominantly sequestered within oil cells (OC) and a spectrum of lipid droplets (LD), whereas the seeds predominantly harbor uniformly-sized LD. The expression patterns of pivotal genes implicated in oil biosynthesis were observed to be markedly contingent upon the tissue type and developmental stage. Notably, the light-responsive fatty acid synthase (FAS) gene demonstrated preferential transcription within the fruit mesocarp. In contrast, genes pivotal for carbon chain elongation, such as 3-ketoacyl-ACP synthase II (KASII) and fatty acyl-ACP thioesterase A (FATA), and desaturation, typified by Stearoyl-ACP desaturase (SAD) and Fatty Acid Desaturase (FAD), were noted to be more robustly transcribed within the seeds. Furthermore, isoenzyme gene families integral to the assembly of triacylglycerol (TAG), including long-chain acyl-CoA synthetases (LACSs), glycerol-3-phosphate acyltransferases (GPATs), and lysophosphatidic acid acyltransferases (LPATs), exhibited pronounced tissue specificity. This research endeavors to clarify the molecular regulatory mechanisms that oversee oil biosynthesis within both seed and non-seed tissues of oilseed-bearing plants with entire fruits. Collectively, these findings lay the groundwork and offer technical scaffolding for future targeted cultivation of woody oil plants, with the ultimate aim of augmenting fruit oil yield and refining FA compositions.

Metabolite concentrations and the expression profiles of the corresponding metabolic pathway genes in eggplant (Solanum melongena L.) fruits of contrasting colors.

Eggplant (Solanum melongena L.) ranks fifth in importance among vegetable crops of the Solanaceae family, in part due to the high antioxidant properties and polyphenol content of the fruit. Along with the popular purple-fruited varieties of S. melongena, there are cultivars, the fruits of which are rich in phenolic compounds, but are white-colored due to the lack of anthocyanin biosynthesis. Determination of the amount of anthocyanins and other phenolic compounds, as well as carotenoids and sugars, is included in the assessment of the quality of eggplant fruits of commercial (technical) ripeness. In addition to antioxidant and taste properties, these metabolites are associated with fruit resistance to various stress factors. In this study, a comparative analysis of the content of anthocyanins, carotenoids and soluble sugars (sucrose, glucose, fructose) in the peel and pulp of the fruit of both technical and biological ripeness was carried out in purple-fruited (cv. Vlas) and white-fruited (cv. Snezhny) eggplant accessions of domestic selection. The peel and pulp of biologically ripe fruits of the cvs Vlas and Snezhny were used for comparative transcriptomic analysis. The key genes of the flavonoid and carotenoid metabolism, sucrose hydrolysis, and soluble sugar transport were shown to be differentially expressed between fruit tissues, both within each cultivar and between them. It has been confirmed that the purple color of the peel of the cv. Vlas fruit is due to substantial amounts of anthocyanins. Flavonoid biosynthesis genes showed a significantly lower expression level in the ripe fruit of the cv. Vlas in comparison with the cv. Snezhny. However, in both cultivars, transcripts of anthocyanin biosynthesis genes (DFR, ANS, UFGT) were not detected. Additionally, the purple fruit of the cv. Vlas accumulated more carotenoids and sucrose and less glucose and fructose than the white fruit of the cv. Snezhny. Biochemical data corresponded to the differential expression pattern of the key genes encoding the structural proteins of metabolism and transport of the compounds analyzed.

Genome-wide identification and expression analysis of the U-box gene family related to biotic and abiotic stresses in Coffea canephora L.

Plant U-box genes play an important role in the regulation of plant hormone signal transduction, stress tolerance, and pathogen resistance; however, their functions in coffee (Coffea canephora L.) remain largely unexplored. In this study, we identified 47 CcPUB genes in the C. canephora L. genome, clustering them into nine groups via phylogenetic tree. The CcPUB genes were unevenly distributed across the 11 chromosomes of C. canephora L., with the majority (11) on chromosome 2 and none on chromosome 8. The cis-acting elements analysis showed that CcPUB genes were involved in abiotic and biotic stresses, phytohormone responsive, and plant growth and development. RNA-seq data revealed diverse expression patterns of CcPUB genes across leaves, stems, and fruits tissues. qRT-PCR analyses under dehydration, low temperature, SA, and Colletotrichum stresses showed significant up-regulation of CcPUB2, CcPUB24, CcPUB34, and CcPUB40 in leaves. Furthermore, subcellular localization showed CcPUB2 and CcPUB34 were located in the plasma membrane and nucleus, and CcPUB24 and CcPUB40 were located in the nucleus. This study provides valuable insights into the roles of PUB genes in stress responses and phytohormone signaling in C. canephora L., and provided basis for functional characterization of PUB genes in C. canephora L.

Elevated zeaxanthin accumulation in fruit and leaf tissues of orange capsicum: can the leaf be used as a phenotypic marker for selection of high-zeaxanthin fruit?

Elevated zeaxanthin accumulation in fruit and leaf tissues of orange capsicum: can the leaf be used as a phenotypic marker for selection of high-zeaxanthin fruit?

Genome-wide investigation of glycoside hydrolase 9 (GH9) gene family unveils implications in orchestrating the mastication trait of Citrus sinensis fruits

Mastication trait of citrus significantly influences the fruit’s overall quality and consumer preference. The accumulation of cellulose in fruits significantly impacts the mastication trait of citrus fruits, and the glycoside hydrolase 9 (GH9) family plays a crucial role in cellulose metabolism. In this study, we successfully identified 32 GH9 genes from the Citrus sinensis genome and subsequently conducted detailed bioinformatics analyses of the GH9 family. Additionally, we profiled the spatiotemporal expression patterns of CsGH9 genes across four distinct fruit tissue types and six crucial developmental stages of citrus fruits, leveraging transcriptome data. Parallel to this, we undertook a comparative analysis of transcriptome profiles and cellulose content among diverse fruit tissues spanning six developmental stages. Furthermore, to identify the pivotal genes involved in cellulose metabolism within the GH9 family during fruit maturity, we employed correlation analysis between cellulose content and gene expression in varying tissues across diverse citrus varieties. This analysis highlighted key genes such as CsGH9A2/6 and CsGH9B12/13/14/22. Collectively, this study provides an in-depth analysis of the GH9 gene family in citrus and offers novel molecular insights into the underlying mechanisms governing the mastication trait formation in citrus fruits.

Replacement of native sugars of apples by isomaltulose in dual stages

The present study aimed to substitute the native sugars of apples for isomaltulose. In the first stage, native sugars were partially removed from the fruit tissue, and in the second stage, isomaltulose was incorporated. The use of ultrasound was evaluated at both process stages. Water loss (WL), solid gain (SG), water activity (aw), soluble solids content (°Brix), shrinkage (Sh), and color parameters (total color difference (ΔE), L* a*, b*, Cr*, and h°) were evaluated. The temperature of 35 °C stood out for its contribution to the mass transfer parameters (SG = 8.196%; WL = 21.699%—maximum values). There seems to be a threshold regarding the use of ultrasound in the process stages, indicating that its excessive use does not favor impregnation. The ideal process to promote the dehydration of apples and incorporation of the greatest amount of isomaltulose consisted of a treatment in which samples were immersed in water in the first stage, followed by impregnation of isomaltulose for 40 min assisted by ultrasound in the second stage. In addition, there was a significant reduction of aw (0.971 ± 0.001) and a slight change in color parameters (2.91 ± 0.45). Only concerning Sh (28.7 ± 3.6%), this treatment was not advantageous.Graphical

Interplay of phenolic compounds and gene expression in phenylpropanoid and flavonoid pathways during olive (Olea europaea L.) ripening of ‘Leccino’ cultivar

This study presents a detailed analysis and interplay of the phenolics, relative gene expression and quality parameters during ripening of ‘Leccino’ olive fruit pulp and skin at seven maturity indexes, in the phenylpropanoid and flavonoid pathways. Tissue-specific gene expression analysis revealed statistically higher expression levels for eight genes in the skin. The only exception was anthocyanidin synthase (ANS), which expression level was statistically higher in the pulp. Our results confirm that the important role in olives of the anthocyanin composition have flavonoid 3′-hydroxylase (F3′H) and flavonoid-3′,5′-hydroxylase (F3′5′H) in both tissues. The phenolic content was mostly statistically higher in the skin than in the pulp and generally increased in both tissues during ripening. A notable shift in phenolic compounds occurs between maturity index 3 and 4, when the skin of the fruit turns completely purple. Results from this study highlight the intricate dynamics of physiological processes and biochemical mechanisms in the phenylpropanoid and flavonoid pathways in olive fruit. The findings also underscore the relationship between phenolic content, relative gene expression, and quality parameters, particularly in relation to color development during ripening in different olive fruit tissues. Our conclusions can be used by growers to improve the quality of fruit and consequently the quality of olive oil or other final products.

Efficacy of methyl anthranilate vapour against Botrytis cinerea in packaged strawberries

The efficacy of methyl anthranilate (MA) vapour in extending the postharvest shelf-life of fresh strawberries has been studied. For that, fruit inoculated with Botrytis cinerea was packaged in vented polypropylene (PP) clamshells and exposed to MA vapour released from a cellulose paper disc impregnated with the liquid compound and placed in the lid of the package. Fruit was stored for 12 days at 4 °C, and fungal growth of berries were monitored throughout storage. The level of fungal infection was significantly reduced in fruit treated with MA vapour. Moreover, packaged fruit with MA vapour that had not been previously inoculated maintained certain quality parameters such as colour and firmness better than control samples. Overall, MA vapour extended the shelf-life of strawberries from 6 to 9 days without causing phytotoxic effects on fruit tissue. MA was absorbed by the fruit but did not surpass the “no observed adverse effect level” (NOAEL). The maximum value of MA in fruit was reached at the end of the storage with a value of 34 µg g−1. Thus, MA presents potential as an antimicrobial volatile for the preservation of packaged strawberries.

First report of bacteria associated with soft rot in yellow pitahaya (Selenicereus megalanthus haw.) in Colombia crops

Colombia is the ninth largest producer of dragon fruit in the world and the department of Boyacá is the largest with 440 hectares planted. Bacterial phytopathogens can cause pitahaya fruit losses and low yields by producing stem soft rot. This research aimed to study and identified possible agents of bacterial diseases of pitahaya in Boyacá, Colombia. Thirteen farms in the region were selected to take 20 samples by means of a targeted and random sampling of stem and fruit tissues with soft rot symptoms in the early stages of the disease. A process of microbiological isolation, biochemical and molecular taxonomic identification of the isolated bacteria. The 16s rRNA gene sequences of the V2-V5 region were edited by removing the primers, assembling and obtaining the consensus sequence of the primers 1100R-337F and 800R -518F. The phylogenetic analysis was performed by BLAST at NCBI, using the “Classifier” and “SeqMatch” tools from the RDP website, and phylogenetic trees were created by multiple alignment using the MUSCLE algorithm and the Tamura Nei distance method was performed. Signs like blisters and mucilaginous fluids, symptoms like yellow and brown chlorotic spots, soft rot, and liquefaction were identified, and possible vectors like flies and ants were report. Twenty-five bacterial morphotypes were identified classifieds in 4 phyla, 9 families and 13 genera. The analysis of the 16S rRNA gene sequences of the bacterial strains showed a 98 to 100% identity with Enterobacter cloacae, Pectobacterium carotovora and Paenibacillus glucanolyticus, reported in other studies as causing the soft rot of the pitahaya stem and fruit. New species were reported as possible pathogenic bacteria of pitahaya: Pantoea cypripedii, Kluyvera intermedia and Klebsiella oxytoca. Infectivity assays did not have positive results. The microbiota identified in the stages of the necrotrophic phase or final stage of soft rot of the stem belong to the genera Achromobacter, Sphingobacterium, Pseudomonas, Klebsiella, Paenibacillus, Bacillus, Stenotrophomonas and Microbacterium. In the fly Leptoglossus zonatus associated with the crop were identified Pseudomonas fulva and Lysinibacillus fusiformis were identified. This is also the first official report of a complex of possible phytopathogen bacteria of the order Enterobacterales (Enterobacteriacea, Erwiniaceae and Pectobacteriaceae family) in symptoms by bacterial disease on pitahaya Colombian crops. Identification of the bacteria in a pathogenic system can guide chemical and biological control practices in order to increase the productive and export potential of exotic and orphan crops from small local farmings.

Genome-Wide Association Study of Cuticle and Lipid Droplet Properties of Cucumber (Cucumis sativus L.) Fruit.

The fruit surface is a critical first line of defense against environmental stress. Overlaying the fruit epidermis is the cuticle, comprising a matrix of cutin monomers and waxes that provides protection and mechanical support throughout development. The epidermal layer of the cucumber (Cucumis sativus L.) fruit also contains prominent lipid droplets, which have recently been recognized as dynamic organelles involved in lipid storage and metabolism, stress response, and the accumulation of specialized metabolites. Our objective was to genetically characterize natural variations for traits associated with the cuticle and lipid droplets in cucumber fruit. Phenotypic characterization and genome-wide association studies (GWAS) were performed using a resequenced cucumber core collection accounting for >96% of the allelic diversity present in the U.S. National Plant Germplasm System collection. The collection was grown in the field, and fruit were harvested at 16-20 days post-anthesis, an age when the cuticle thickness and the number and size of lipid droplets have stabilized. Fresh fruit tissue sections were prepared to measure cuticle thickness and lipid droplet size and number. The collection showed extensive variation for the measured traits. GWAS identified several QTLs corresponding with genes previously implicated in cuticle or lipid biosynthesis, including the transcription factor SHINE1/WIN1, as well as suggesting new candidate genes, including a potential lipid-transfer domain containing protein found in association with isolated lipid droplets.

Recent Advances in Light Penetration Depth for Postharvest Quality Evaluation of Fruits and Vegetables.

Light penetration depth, as a characteristic parameter reflecting light attenuation and transmission in biological tissues, has been applied in nondestructive detection of fruits and vegetables. Recently, with emergence of new optical detection technologies, researchers have begun to explore methods evaluating optical properties of double-layer or even multilayer fruit and vegetable tissues due to the differences between peel and pulp in the chemical composition and physical properties, which has gradually promoted studies on light penetration depth. A series of demonstrated research on light penetration depth could ensure the accuracy of the optical information obtained from each layer of tissue, which is beneficial to enhance detection accuracy for quality assessment of fruits and vegetables. Therefore, the aim of this review is to give detailed outlines about the theory and principle of light penetration depth based on several emerging optical detection technologies and to focus primarily on its applications in the field of quality evaluation of fruits and vegetables, its future applicability in fruits and vegetables and the challenges it may face in the future.

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.

Nickel and Soil Fertility: Review of Benefits to Environment and Food Security

Nickel (Ni) is an essential micronutrient for plants, responsible for metabolizing urea nitrogen (urea-N) by urease and mitigating abiotic and oxidative stresses through the glyoxalase (Gly) and glutathione (GSH) cycles. However, excess Ni is toxic to flora at >100 mg kg−1, except for hyperaccumulators that tolerate >1000 mg kg−1 Ni. This review discusses the benefits of Ni nutrient management for soil fertility, improving food security, and minimizing adverse environmental impacts from urea overapplication. Many farming soils are Ni deficient, suggesting that applying 0.05–5 kg ha−1 of Ni improves yield and urea-N use efficiency. Applied foliar and soil Ni fertilizers decrease biotic stresses primarily by control of fungal diseases. The bioavailability of Ni is the limiting factor for urease synthesis in plants, animal guts, and the soil microbiome. Improved urease activity in plants and subsequently through feed in livestock guts reduces the release of nitrous oxide and nitrite pollutants. Fertilizer Ni applied to crops is dispersed in vegetative tissue since Ni is highly mobile in plants and is not accumulated in fruit or leafy tissues to cause health concerns for consumers. New methods for micronutrient delivery, including rhizophagy, recycled struvite, and nanoparticle fertilizers, can improve Ni bioavailability in farming systems.