Targeted/untargeted metabolomics and antioxidant properties distinguish Citrus reticulata 'Chachi' from Citrus reticulata Blanco.

Dried citrus peel (DCP), also called "Chen Pi", has edible and medicinal value. However, the specific differences among various sources remain unknown. Herein, we collected six DCP species, namely, one Citrus reticulata 'Chachi' (CZG) and five Citrus reticulata Blanco (CRB). Targeted high-performance liquid chromatography and untargeted ultra-high-performance liquid chromatography-tandem mass spectrometry were employed to comprehensively compare the phenolic compounds and metabolites in DCP. Interestingly, 13 different phenolic compounds were noted in DCP. The total phenolic compound content in all CRB samples (58.86-127.65 mg/g) was higher than that of CZG (39.47 mg/g). Untargeted metabolomic revealed 1495 compounds, with 115 differentially expressed metabolites for CRBs and CZG, particularly flavonoids (38), terpenoids (15), and phenolic acids and derivatives (9). Lastly, antioxidant assays revealed that all CRB samples exhibited higher antioxidant activities compared with CZG. Therefore, our study results provide a theoretical basis for the high-value utilization of citrus peels and their metabolites.

[Quality identification of Aurantii Fructus Immaturus from different origins and their adulterants].

Aurantii Fructus Immaturus(AFI) is a traditional Chinese herbal medicine with multiple origins from Citrus aurantium and its legally cultivated variants. With advancements in agricultural biotechnology, many new cultivated varieties have sprung up,leading to an abundance of AFI adulterants and chaos in the herbal medicine markets. This study developed a specific identification method for AFI and its closely related adulterants by examining the appearance trait, content of extract, and multiple ingredients,involving indicators such as the ratio of pulp capsule to cross section diameter(Pc/Cs ratio), the content of extract, and the profile of 11 ingredients. The research finds that:(1) Pc/Cs ratio can conveniently identify adulterants such as Poncirus trifoliata, Ju, and Babagan from the genuine AFI.(2) The extract content can be used to identify adulterants originated from C. wilsonii with C. aurantium.(3) The contents of synephrine in all the samples were in accordance with the Chinese Pharmacopoeia except for the adulterants from P. trifoliata, C. wilsonii, C. aurantium 'Changshanhuyou' and orah mandarins. The synephrine content was high as 1. 40% in some C. sinensis varieties. The mass fraction of hesperidin was over 10. 00% in C. sinensis, while it was below 2. 50% in C. aurantium. C. aurantium contained high levels of naringin(3. 96%-15. 21%) and neo-hesperidin(9. 38%-21. 93%).(4) The compositions of adulterants from P. trifoliata and C. wilsonii were more similar to that of C. aurantium 'Daidai', but with significantly lower neo-hesperidin content(0. 03%-0. 14%) than that in C. aurantium, and they lacked hesperetin and tangeretin. C. maxima(originating from C. maxima) showed closer composition to Choucheng and hybrid originated from Citrus aurantium × Poncirus trifoliata, but had higher hesperidin content(3. 13%) than that in C. aurantium. Ju was closely related to C. sinensis and neither contained naringin nor neo-hesperidin. Hesperidins in Babagan and orah mandarins were similar to that in C. sinensis, with none containing rhoifolin. These quality indicators in combination can accurately distinguish between C. sinensis, C. aurantium, and their closely related adulterants(P. trifoliata, C. wilsonii, C. maxima, orah mandarins and C. reticulata), which are expected to provide a systematic method for quality control of AFI.

The genomes of Australian wild limes.

Australian wild limes occur in highly diverse range of environments and are a unique genetic resource within the genus Citrus. Here we compare the haplotype-resolved genome assemblies of six Australian native limes, including four new assemblies generated using PacBio HiFi and Hi-C sequencing data. The size of the genomes was between 315 and 391 Mb with contig N50s from 29.5 to 35 Mb. Gene completeness of the assemblies was estimated to be from 98.4 to 99.3% and the annotations from 97.7 to 98.9% based upon BUSCO, confirming the high contiguity and completeness of the assembled genomes. High collinearity was observed among the genomes and the two haplotype assemblies for each species. Gene duplication and evolutionary analysis demonstrated that the Australian citrus have undergone only one ancient whole-genome triplication event during evolution. The highest number of species-specific and expanded gene families were found in C. glauca and they were primarily enriched in purine, thiamine metabolism, amino acids and aromatic amino acids metabolism which might help C. glauca to mitigate drought, salinity, and pathogen attacks in the drier environments in which this species is found. Unique genes related to terpene biosynthesis, glutathione metabolism, and toll-like receptors in C. australasica, and starch and sucrose metabolism genes in both C. australis and C. australasica might be important candidate genes for HLB tolerance in these species. Expanded gene families were not lineage specific, however, a greater number of genes related to plant-pathogen interactions, predominantly disease resistant protein, was found in C. australasica and C. australis.

[Production of neohesperidin from hesperetin by an engineered strain of Escherichia coli].

Neohesperidin is a flavonoid glycoside widely used in the food and pharmaceutical industries. The current production of neohesperidin mainly relies on extraction from plants. Microbial fermentation demonstrates a promising prospect as an environmentally friendly, efficient, and economical method. In this study, we designed and constructed the biosynthetic pathway of neohesperidin in an Escherichia coli strain by introducing the glycosyltransferase UGT73B2 from Arabidopsis thaliana, rhamnose synthase VvRHM-NRS from Vitis vinifera, and rhamnose transferase Cm1,2RhaT from Citrus maxima. After optimization of the module and the uridine diphosphate (UDP)-glucose synthetic pathway, the engineered strain produced 4.64 g/L neohesperidin in a 5 L bioreactor, and the molar conversion rate of hesperetin was 45.8%. This has been the highest titer reported to date for the biosynthesis of neohesperidin in microorganisms. This study lays a foundation for the construction and application of strains with high yields of neohesperidin and provides a potential choice for the microbial production of other flavonoid glycosides.

Synthesis and characterization of Lanthanum Oxide nanoparticles using Citrus aurantium and their effects on Citrus limon Germination and Callogenesis.

The plant extract-mediated method is eco-friendly, simple, safe, and low-cost, using biomolecules as a reducing agent to separate nanoparticles. Lanthanum (La) is a rare earth metal that positively affects plant growth and agriculture. Citrus limon is a leading citrus fruit with many varieties. Conventional vegetative propagation methods depend on season, availability of plant material and are time-consuming. It is the main reason for limiting the acceptance of new varieties. So, In-vitro propagation of the lemon method is practiced overcoming all these problems. Lanthanum oxide nanoparticles (La2O3-NPs) were synthesized using plant extract of C. aurantium. Ultraviolet (UV)-Visible Spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared (FTIR) spectroscopy, and Thermal Gravimetric Analysis (TGA) were used to characterize the synthesized La2O3-NPs. Fabricated La2O3-NPs were oval and spherical, with an average size of 51.1 nm. UV-visible absorption spectra of La2O3-NPs were shown at a sharp single peak at 342 nm and FTIR showed stretching frequency at 455 cm-1-516 cm-1. In the TGA outcome, mass loss was 9.1%. In vitro experiments demonstrated that La2O3-NPs significantly enhanced the germination and growth of C. limon seeds, achieving an 83% germination rate at 5 mg/L concentration, with uncoated seeds showing root initiation at 10 days and shoot formation at 15 days. Furthermore, La2O3-NPs effectively stimulated callus induction and maturation, with optimal responses observed in media containing MS and 2 mg/L 2,4-D, resulting in a maximum callus frequency of 100% from leaves and 87.5% from shoots at 5 mg/L concentration. These findings underscore the potential of La2O3-NPs to improve seed germination rates, seedling vigor, and callogenesis efficiency, suggesting their promising integration into agricultural practices for sustainable crop production, especially in suboptimal growing conditions. Future research is recommended to explore the mechanisms and broader applications of La2O3-NPs across various plant species and environments.

Whole genome sequences of 135 "Candidatus Liberibacter asiaticus" strains from China.

"Candidatus Liberibacter asiaticus" (CLas) is a phloem-limited alpha-proteobacteria causing Citrus Huanglongbing, the destructive disease currently threatening global citrus industry. Genomic analyses of CLas provide insights into its evolution and biology. Here, we sequenced and assembled whole genomes of 135 CLas strains originally from 20 citrus cultivars collected at ten citrus-growing provinces in China. The resulting dataset comprised 135 CLas genomes ranging from 1,221,309 bp to 1,308,521 bp, with an average coverage of 675X. Prophage typing showed that 44 strains contained Type 1 prophage, 89 strains contained Type 2 prophage, 44 strains contained Type 3 prophage, and 34 of them contained more than one type of prophage/phage. The SNP calling identified a total of 5,090 SNPs. Genome-based phylogenetic analysis revealed two major clades among CLas strains, with Clade I dominated by CLas strains containing Type 1 prophage (79/95) and Clade II dominated by CLas strains containing Type 1 or Type 3 prophage (80/95). This CLas genome dataset provides valuable resources for studying genetic diversity and evolutionary pattern of CLas strains.

Sorption and degradation processes of imidacloprid in Florida soils.

Imidacloprid (IDP) is an active ingredient of the Admire brand pesticide used to control the vector (Asian citrus psyllid) that transmits the causative organism Candidatus Liberibacter asiaticus (CLas) for citrus greening or huanglongbing disease. Imidacloprid products are applied via soil drench where citrus roots are mostly concentrated which is between 0 and 60 cm depth. These soil depths exhibit different characteristics that may affect IDP leaching beyond the rooting zone. Representative soil samples were collected from Entisols and Ultisols, which are the dominant soil orders under citrus production in central Florida, at 15 cm increments up to 60 cm to estimate and understand the batch sorption, kinetics, equilibria, and degradation of IDP. Results showed that the equilibrium time for IDP at 0-15 cm depth (10 hours) was 2 times faster than at 15-60 cm (20 hours) for the Entisol. Nevertheless, all depths reached equilibrium within 24 hours for the Entisol. The 0-30 cm depth adsorbed 2 times more IDP than the 30-60 cm depth for both soils. Nevertheless, the adsorption coefficient was approximately ≤ 1 mL g-1 for both soils. The half-life of IDP in both soils ranged from 10 to 17 days. The Entisol showed higher adsorption than the Ultisol at both depths, probably due to relatively lower organic carbon (OC) content in the Ultisol compared to the Entisol. Thus, the Ultisol showed high IDP leaching vulnerability compared to the Entisol. Movement of IDP is affected by the amount of OC in the citrus critical zone.

Characterization of Lactic Acid Bacteria Isolated From Rotting Oranges and Use of Agropastoral Processing By-products as Carbon and Nitrogen Sources Alternative for Lactic Acid Production.

This study investigated the ability of lactic acid bacteria (LAB) isolated from oranges to use fish by-products (FB) and chicken by-products (CB) as nitrogen sources alternative to yeast extract for lactic acid (LA) production in a papaya by-product medium as a carbon source. Once the fermentation agents had been isolated, they were subjected to biochemical and molecular characterization. Inexpensive nitrogen sources, precisely CB and FB, were prepared, freeze-dried, and yield evaluated. Also, before to the fermentation experiments, the Total Kjehdahl Nitrogen (TKN) of these by-products and that of the yeast extract were determined. Then, three production media differing in terms of nitrogen source were formulated from these nitrogen sources. From the 22 LAB isolated from orange, two isolates of interest (NGO25 and NGO23) were obtained; all belonging to the Lactiplantibacillus plantarum species based on 16S rRNA gene sequencing. Furthermore, the production yield powder obtained after lyophilization of 1 L of CB and FB surpernatant were, respectively, 16.6 g and 12.933 g. The TKN of different nitrogen sources powder were 71.4 ± 0.000% DM (FB), 86.145 ± 0.001% DM (CB), and 87.5 ± 0.99% DM (yeast extract). The best kinetic parameters of LA production (LA (g/L): 31.945 ± 0.078; volumetric productivity (g/L.h): 1.331 ± 0.003; LA yield (mg/g) 63.89 ± 0.156; biomass (g/L) 7.925 ± 0.035; cell growth rate (g/L.h): 0.330 ± 0.001) were recorded by Lactiplantibacillus plantarum NGO25 after 24 h of fermentation. The latter data were obtained in the production medium containing CB as nitrogen sources. In addition, this production medium cost only $0.152 to formulate, compared to yeast extract which required $1.692 to formulate. Thus, freeze-dried CB can be used as an alternative to yeast extract in large-scale production of LA.

Combination of Cinnamaldehyde/ß-cyclodextrin inclusion complex and L-phenylalanine effectively reduces the postharvest green mold in citrus fruit.

The essential oil and ß-cyclodextrin inclusion complex was able to inhibit the growth of Penicillium digitatum, a damaging pathogen that causes green mold in citrus fruit. In this study, cinnamaldehyde-ß-cyclodextrin inclusion complex (ß-CDCA) for controlling citrus green mold was synthesized by the co-precipitation method. Characterization of ß-CDCA revealed that the aromatic ring skeleton of cinnamaldehyde (CA) was successfully embedded into the cavity of ß-CD to form the inclusion complex. ß-CDCA inhibited P. digitatum at a minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of 4.0 g/L. FT-IR spectroscopy analysis, calcofluor white staining, extracellular alkaline phosphatase (AKP) activity and propidium iodide (PI) staining of hyphae morphology showed that ß-CDCA may damage the cell ultrastructure and membrane permeability of P. digitatum. The study further demonstrated that hydrogen peroxide (H2O2), malondialdehyde (MDA), and reactive oxygen species (ROS) markedly accumulated in 1/2 MIC ß-CDCA treated hyphae. This implied that ß-CDCA inhibited growth of P. digitatum by the triggering oxidative stress, which may have caused cell death by altering cell membrane permeability. In addition, in vivo results showed that ß-CDCA alone or combined with L-phenylalanine (L-PHe) displayed a comparable level to that of prochloraz. Therefore, ß-CDCA combined with L-PHe can thus be used as an eco-friendly preservative for the control green mold in postharvest citrus fruit.

Inhibitory mechanism of 4-ethyl-1,2-dimethoxybenzene produced by Streptomyces albidoflavus strain ML27 against Colletotrichum gloeosporioides.

Actinomycetes have emerged as significant biocontrol resources due to their rich array of bioactive natural products. While much research has historically focused on secondary metabolites isolated from their fermentation broth, there remains a dearth of reports on their volatile organic compounds (VOCs). Here, strain ML27, isolated from soil, was identified as Streptomyces albidoflavus based on morphological features, physiological, biochemical, and molecular characteristics (16S rRNA, atpD, recA, and rpoB gene sequences). VOCs from S. albidoflavus strain ML27 were effectively captured using solid-phase microextraction (SPME) and tentatively identified through gas chromatography-mass spectrometry (GC/MS). Among these compounds, 4-ethyl-1,2-dimethoxybenzene exhibited broad-spectrum antifungal activity and demonstrated efficacy in controlling citrus anthracnose, with a control efficacy of 86.67%. Furthermore, the inhibitory mechanism of 4-ethyl-1,2-dimethoxybenzene against Colletotrichum gloeosporioides was revealed. Results indicated that 4-ethyl-1,2-dimethoxybenzene induced swelling, deformity, and breakage in C. gloeosporioides mycelia, and significantly inhibited spore germination. Transcriptome analysis revealed that 4-ethyl-1,2-dimethoxybenzene inhibited the growth and development of C. gloeosporioides primarily by disrupting energy metabolism and the integrity of the cell wall and membrane. Based on these results, it is promising to develop 4-ethyl-1,2-dimethoxybenzene as a novel biopesticide for controlling citrus anthracnose.

Toxicity and enzymatic mechanism of Citrus spp. essential oils and major constituents on Haemaphysalis longicornis (Acari: Ixodidae) and non-target Harmonia axyridis (Coleoptera: Coccinellidae).

Plant essential oils (EOs)-based acaricides have been recognized as environmentally-friendly alternatives to synthetic acaricides because of their low toxicity against non-target species. Despite this, there are knowledge gaps regarding the toxicity mechanisms of plant EOs against non-target species. Here, the toxicology and enzymatic mechanism of Citrus reticulata and Citrus lemon EOs were evaluated against the vector pest, Haemaphysalis longicornis, and non-target ladybird beetle, Harmonia axyridis. Both EOs were mainly composed of d-Limonene, followed by ß-Myrcene and γ-Terpinene in C. reticulata, and (-)-ß-Pinene and γ-Terpinene in C. lemon. Citrus reticulata and C. lemon EOs were toxic to Hae. longicornis, with 50 % lethal concentration (LC50) values estimated at 0.43 and 0.98 µL/mL via nymphal immersion test, and 42.52 and 46.38 µL/mL via spray application, respectively. Among the constituents tested, ß-Myrcene was the most effective, with LC50 values of 0.17 and 47.87 µL/mL via immersion and spray treatment, respectively. A significant mortality of non-target Har. axyridis was found when treated by the EOs at concentrations two times greater than LC50 estimated against H. longicornis. The biochemical assay revealed that the EOs induced changes in the antioxidant enzyme activity of superoxide dismutases, catalase, and glutathione peroxidase in Hae. longicornis and Har. axyridis. The results demonstrated the acaricidal potential of citrus EOs and their major constituents for tick control, revealed the risk of the EOs to non-target species, and provided relevant insights into the mechanisms underlying their toxicity.

LCA analysis for assessing environmenstal sustainability of new biobased chemicals by valorising citrus waste.

The global shift towards using biomass for biofuels and chemicals is accelerating due to increasing environmental concerns and geopolitical strategies. This study investigates a biorefinery model using citrus-processing-waste, specifically citrus pulp, to produce high-value products for various industries, including cosmetics, pharmaceuticals, flavours, fragrances, and food packaging. In Italy, particularly Sicily region, citrus processing generates significant amounts of waste, often improperly disposed of, contributing to environmental problems. Researchers have demonstrated that citrus waste can yield commercially valuable compounds. This study specifically focuses on orange peel waste (OPW), which constitutes about half of the fruit's weight, aiming to extract pectin and limonene through a combined process. The extraction process was carried out on a laboratory scale, and its sustainability was evaluated using a life cycle assessment (LCA) with SimaPro 8.1 software and the Impact 2002 + method. The functional unit adopted for this study is 300 g of OPW, obtained after the pre-treatment phase, from which 0.14 g of limonene and 8.22 g of pectin were extracted. The LCA results revealed that pectin extraction has a significantly higher environmental impact compared to limonene extraction, primarily due to the use of ethanol as a solvent, followed by electricity consumption. To mitigate this impact, the LCA assessed alternative, more sustainable solvents, resulting in a 73.4% reduction in the environmental footprint of the pectin extraction process. These findings underscore the critical role of LCA, even at the laboratory scale, in identifying environmental hotspots and providing insights for improving and optimizing processes for potential industrial-scale applications.

Assessment of the in vitro anti-diabetic activity with molecular dynamic simulations of limonoids isolated from Adalia lemon peels.

Limonoids are important constituents of citrus that have a significant impact on promoting human health. Therefore, the primary focus of this research was to assess the overall limonoid content and isolate limonoids from Adalia lemon (Citrus limon L.) peels for their potential use as antioxidants and anti-diabetic agents. The levels of limonoid aglycones in the C. limon peel extract were quantified through a colorimetric assay, revealing a concentration of 16.53 ± 0.93 mg/L limonin equivalent. Furthermore, the total concentration of limonoid glucosides was determined to be 54.38 ± 1.02 mg/L. The study successfully identified five isolated limonoids, namely limonin, deacetylnomilin, nomilin, obacunone 17-O-ß-D-glucopyranoside, and limonin 17-O-ß-D-glucopyranoside, along with their respective yields. The efficacy of the limonoids-rich extract and the five isolated compounds was evaluated at three different concentrations (50, 100, and 200 µg/mL). It was found that both obacunone 17-O-ß-D-glucopyranoside and limonin 17-O-ß-D-glucopyranoside possessed the highest antioxidant, free radical scavenging, and anti-diabetic activities, followed by deacetylnomilin, and then the limonoids-rich extract. The molecular dynamic simulations were conducted to predict the behavior of the isolated compounds upon binding to the protein's active site, as well as their interaction and stability. The results revealed that limonin 17-O-ß-D-glucopyranoside bound to the protein complex system exhibited a relatively more stable conformation than the Apo system. The analysis of Solvent Accessible Surface Area (SASA), in conjunction with the data obtained from Root-Mean-Square Deviation (RMSD), Root-Mean-Square Fluctuation (RMSF), and Radius of Gyration (ROG) computations, provided further evidence that the limonin 17-O-ß-D-glucopyranoside complex system remained stable within the catalytic domain binding site of the human pancreatic alpha-amylase (HPA)-receptor. The research findings suggest that the limonoids found in Adalia lemon peels have the potential to be used as effective natural substances in creating innovative therapeutic treatments for conditions related to oxidative stress and disorders in carbohydrate metabolism.

Arabinan branches in the RG-I region of citrus pectin aid acid-induced gelation.

Gelation is a critical property of citrus pectin. However, the roles played by neutral sugar side-chains on acid-induced pectin gelation remain poorly understood. Herein, galactan- or/and arabinan-eliminated pectins (P-G, P-A, and P-AG) were used to investigate the effects of side-chains on gelation. The gel hardness values of citrus pectin, P-G, P-A, and P-AG were 42.6, 39.9, 5.3, and 2.1 g, respectively, suggesting that arabinan contributed more to gelation than galactan. We next found that arabinan branches promoted pectin chain entanglement more effectively than arabinan backbones. Destabilizer addition experiments showed that hydrogen bonding, electrostatic interaction, and hydrophobic interaction were the main forces affecting pectin gel networks and strength, which was further validated by molecular dynamic simulations. The total number of hydrogen bonds between the arabinan branches and galactan/HG (65.7) was significantly higher than that between the arabinan backbones and galactan/HG (39.1), indicating that arabinan branches predominated in terms of such interactions. This study thus elucidated the roles played by neutral-sugar side-chains, especially the arabinan branches of acid-induced pectin gels, in term of enhancing high-methoxyl pectin gelation, and offers novel insights into the structure-gelling relationships of citrus pectin.

Nanoparticle LDH enhances RNAi efficiency of dsRNA in piercing-sucking pests by promoting dsRNA stability and transport in plants.

Piercing-sucking pests are the most notorious group of pests for global agriculture. RNAi-mediated crop protection by foliar application is a promising approach in field trials. However, the effect of this approach on piercing-sucking pests is far from satisfactory due to the limited uptake and transport of double strand RNA (dsRNA) in plants. Therefore, there is an urgent need for more feasible and biocompatible dsRNA delivery approaches to better control piercing-sucking pests. Here, we report that foliar application of layered double hydroxide (LDH)-loaded dsRNA can effectively disrupt Panonychus citri at multiple developmental stages. MgAl-LDH-dsRNA targeting Chitinase (Chit) gene significantly promoted the RNAi efficiency and then increased the mortality of P. citri nymphs by enhancing dsRNA stability in gut, promoting the adhesion of dsRNA onto leaf surface, facilitating dsRNA internalization into leaf cells, and delivering dsRNA from the stem to the leaf via the vascular system of pomelo plants. Finally, this delivery pathway based on other metal elements such as iron (MgFe-LDH) was also found to significantly improve the protection against P. citri and the nymphs or larvae of Diaphorina citri and Aphis gossypii, two other important piercing-sucking hemipeteran pests, indicating the universality of nanoparticles LDH in promoting the RNAi efficiency and mortality of piercing-sucking pests. Collectively, this study provides insights into the synergistic mechanism for nano-dsRNA systemic translocation in plants, and proposes a potential eco-friendly control strategy for piercing-sucking pests.

Spatial chemistry of citrus reveals molecules bactericidal to Candidatus Liberibacter asiaticus.

Huanglongbing (HLB), associated with the psyllid-vectored phloem-limited bacterium, Candidatus Liberibacter asiaticus (CLas), is a disease threat to all citrus production worldwide. Currently, there are no sustainable curative or prophylactic treatments available. In this study, we utilized mass spectrometry (MS)-based metabolomics in combination with 3D molecular mapping to visualize complex chemistries within plant tissues to explore how these chemistries change in vivo in HLB-infected trees. We demonstrate how spatial information from molecular maps of branches and single leaves yields insight into the biology not accessible otherwise. In particular, we found evidence that flavonoid biosynthesis is disrupted in HLB-infected trees, and an increase in the polyamine, feruloylputrescine, is highly correlated with an increase in disease severity. Based on mechanistic details revealed by these molecular maps, followed by metabolic modeling, we formulated and tested the hypothesis that CLas infection either directly or indirectly converts the precursor compound, ferulic acid, to feruloylputrescine to suppress the antimicrobial effects of ferulic acid and biosynthetically downstream flavonoids. Using in vitro bioassays, we demonstrated that ferulic acid and bioflavonoids are indeed highly bactericidal to CLas, with the activity on par with a reference antibiotic, oxytetracycline, recently approved for HLB management. We propose these compounds should be evaluated as therapeutics alternatives to the antibiotics for HLB treatment. Overall, the utilized 3D metabolic mapping approach provides a promising methodological framework to identify pathogen-specific inhibitory compounds in planta for potential prophylactic or therapeutic applications.

Novel neuropharmacological activity of citrus lime (Citrus aurantifolia): A standardized lime peel supplement enhances non-rapid eye movement sleep by activating the GABA type A receptor.

Polyphenols have been well-established to exert sedative-hypnotic effects in psychopharmacology. Lime (Citrus aurantifolia) peel is rich in biologically active polyphenols; however, the effects of lime peel extract on sleep have not yet been demonstrated. A comparison was conducted in mice, between the sleep-promoting effects of a standardized lime peel supplement (SLPS) and a well-known hypnotic drug, zolpidem, and its hypnotic mechanism was investigated using in vivo and in vitro assays. The effects of SLPS on sleep were assessed using a pentobarbital-induced sleep test and sleep architecture analysis based on recording electroencephalograms and electromyograms. Additionally, a GABAA receptor binding assay, electrophysiological measurements, and in vivo animal models were used to elucidate the hypnotic mechanism. SLPS (200 and 400 mg/kg) was found to significantly decrease sleep latency and increase the amount of non-rapid eye movement sleep without altering delta activity. The hypnotic effects of SLPS were attributed to its flavonoid-rich ethyl acetate fraction. SLPS had a binding affinity to the GABA-binding site of the GABAA receptor and directly activated the GABAA receptors. The hypnotic effects and GABAA receptor activity of SLPS were completely blocked by bicuculline, a competitive antagonist of the GABAA receptor, in both in vitro and in vivo assays. To the best of our knowledge, this study is the first to demonstrate the hypnotic effects of SLPS, which acts via the GABA-binding site of the GABAA receptor. Our results suggest that lime peel, a by-product abundantly generated during juice processing, can potentially be used as a novel sedative-hypnotic.

Influence of pH on the emulsifying property of high methyl-esterified citrus pectin in the presence of calcium cations.

High methyl-esterified citrus pectin (HMCP) is often used as a thickness in food products and is considered a poor emulsifier, especially in neutral pH solutions. Our previous findings show that the emulsifying capacity of HMCP could be significantly enhanced by calcium cations. Besides, the pH of the solution decreased in the presence of calcium cations. However, the impact of solution pH on HMCP emulsifying capacity in the presence of calcium cations is unclear. In this study, the pH of the HMCP solution was adjusted from 3.00 to 8.00 before adding calcium cations. The solution properties and emulsifying properties were analyzed in light of the existence of calcium cations. The results showed that the pH of the HMCP solutions decreased after bringing calcium cations into them. Calcium cations could change the solution rheological properties, particle size distributions and morphologies, and the particle microenvironmental hydrophobic areas in HMCP solutions while increasing the pH of HMCP solutions, contributing to improving the emulsifying capacity of HMCP. HMCP had the best emulsifying ability when the pH of the HMCP solutions was kept at a neutral level. This research gives us new ideas to adjust the emulsifying property of HMCP.

Transcriptome analysis of Citrus Aurantium L. to study synephrine biosynthesis during developmental stages.

Citrus aurantium L., sometimes known as "sour orange," is an important Chinese herb with young, immature fruits, or "zhishi," that are high in synephrine. Synephrine is a commonly utilized natural chemical with promising applications in effectively increasing metabolism, heat expenditure, energy level, oxidative fat, and weight loss. However, little is known about the genes and pathways involved in synephrine production during the critical developmental stages of C. aurantium L., which limits the development of the industry. According to this study, the concentration of synephrine gradually decreased as the fruit developed. Transcriptome sequencing was used to examine the DEGs associated with synephrine connections and served as the foundation for creating synephrine-rich C. aurantium L. Comparisons conducted between different developmental stages to obtain DEGs, and the number of DEGs varied from 690 to 3,019. Tyrosine and tryptophan biosynthesis, glycolysis/gluconeogenesis, pentose phosphate pathway, phenylalanine, and tyrosine metabolism were the main KEGG pathways that were substantially enriched. The results showed that 25 genes among these KEGG pathways may be related to synephrine synthesis. The WGCNA and one-way ANOVA analysis adoption variance across the groups suggested that 11 genes might play a crucial role in synephrine synthesis and should therefore be further analyzed. We also selected six DEGs at random and analyzed their expression levels by RT-qPCR, and high repeatability and reliability were demonstrated by our finished RNA-seq study results. These results may be useful in selecting or modifying genes to increase the quantity of synephrine in sour oranges.

Coordination between water relations strategy and carbon investment in leaf and stem in six fruit tree species.

The water relation strategy is a key issue in climate change. Given the difficulty of determining water relations strategy, there is a need for simple traits with a solid theoretical basis to estimate it. Traits associated with resource allocation patterns along a 'fast-slow' plant economics spectrum are particularly compelling, reflecting trade-offs between growth rate and carbon allocation. Avocado (Persea americana ), fig tree (Ficus carica ), mandarin (Citrus reticulata ), olive (Olea europaea ), pomegranate (Punica granatum ), and grapevine (Vitis vinifera ) were characterised in terms of iso-anisohydric strategy through stomatal behaviour, water potential at the turgor loss point (TLP), and hydroscape area. Additionally, the association of these metrics with leaf mass per area (LMA) and wood density (WDen) was explored. We observed high coordination between LMA and WDen, and both traits were related to metrics of water relation strategy. More anisohydric species tended to invest more carbon per unit leaf area or unit stem volume, which has implications for hydraulic efficiency and water stress tolerance. WDen and TLP were the most powerful traits in estimating the water relation strategy for six fruit species. These traits are easy to measure, time-cost efficient, and appear central to coordinating multiple traits and behaviours along the water relations strategies.