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Introduction: Antibiotic resistance represents one of the most significant threats to public health in the 21st century. Polyphenols, natural molecules with antibacterial activity produced by plants, are being considered as alternative antimicrobial strategies to manage infections caused by drug-resistant bacteria. In this study, we investigated the antibacterial activity of a polyphenol mixture extracted from citrus fruits, against both antibiotic-susceptible and resistant strains of Staphylococcus aureus and Staphylococcus epidermidis. Methods: Broth microdilution and time-kill curve experiments were used to test the extract anti-staphylococcal activity. Cytotoxicity was assessed by the hemolysis assay. The interaction between the mixture and antibiotics was investigated by the checkerboard assay. The effect of B alone and in combination with oxacillin on the membrane potential was investigated by the 3,3'-dipropylthiadicarbocyanine iodide assay. The ability of the extract to induce the development of resistance was verified by propagating S. aureus for 10 transfers in the presence of sub-inhibitory concentrations. Results: The citrus extract was found to be active against all Staphylococcus strains at remarkably low concentrations (0.0031 and 0.0063%), displaying rapid bactericidal effects without being toxic on erythrocytes. In particular, B was found to rapidly cause membrane depolarization. When combined with methicillin, meropenem, and oxacillin, the mixture displayed synergistic activity exclusively against methicillin-resistant strains. We additionally show that the sequential exposure of S. aureus to sub-inhibitory concentrations did not induce the development of resistance against the extract. Discussion: Overall, these findings support the potential use of the citrus extract as promising option to manage staphylococcal infections and suggest that it may counteract the mechanism behind methicillin-resistance. [ABSTRACT FROM AUTHOR]

Self-incompatibility (SI) is a crucial mechanism that prevents self-fertilization and inbreeding in flowering plants. Citrus exhibits SI regulated by a polymorphic S -locus containing an S-RNase gene and multiple S -locus F-box (SLF) genes. It has been documented that S-RNase functions as the pistil S determinant, but there is no direct evidence that the SLF genes closely linked with S-RNase function as pollen S determinants in Citrus. This study assembled the genomes of two pummelo (Citrus grandis) plants, obtained three novel complete and well-annotated S -haplotypes, and isolated 36 SLF or SLF-like alleles on the S -loci. Phylogenetic analysis of 138 SLFs revealed that the SLF genes were classified into 12 types, including six types with divergent or missing alleles. Furthermore, transformation experiments verified that the conserved S6-SLF7a protein can lead to the transition of SI to self-compatibility by recognizing non-self S8-RNase in 'Mini-Citrus' plants (S 7 S 8 and S 8 S 29 , Fortunella hindsii), a model plant for citrus gene function studies. In vitro assays demonstrated interactions between SLFs of different S haplotypes and the Skp1–Cullin1–F-box subunit CgSSK1 protein. This study provides direct evidence that SLF controls the pollen function in Citrus , demonstrating its role in the 'non-self recognition' SI system. [ABSTRACT FROM AUTHOR]

Background: Bitter orange (Citrus aurantium) is a fruiting shrub native to tropical and subtropical countries around the world and cultivated in many regions due to its nutraceutical value. The current study investigated the metabolic profiling and enzyme inhibitory activities of volatile constituents derived from the C. aurantium peel cultivated in Egypt by three different extraction methods. Methods: The volatile chemical constituents of the peel of C. aurantium were isolated using three methods; steam distillation (SD), hydrodistillation (HD), and microwave-assisted hydrodistillation (MAHD), and then were investigated by GC-MS. The antioxidant potential was evaluated by different assays such as DPPH, ABTS, FRAP, CUPRAC, and phosphomolybdenum and metal chelating potential. Moreover, the effect of enzyme inhibition of the three essential oils was tested using BChE, AChE, tyrosinase, glucosidase, as well as amylase assays. Results: A total of six compounds were detected by GC/MS analysis. The major constituent obtained by all three extraction methods was limonene (98.86% by SD, 98.68% by HD, and 99.23% by MAHD). Differences in the composition of the compounds of the three oils were observed. The hydrodistillation technique has yielded the highest number of compounds, notably two oxygenated monoterpenes: linalool (0.12%) and α-terpineol acetate (0.1%). Conclusion: In our study differences in the extraction methods of C. aurantium peel oils resulted in differences in the oils' chemical composition. Citrus essential oils and their components showed potential antioxidant, anticholinesterase, antimelanogenesis, and antidiabetic activities. The presence of linalool and α-terpineol acetate may explain the superior activity observed for the oil isolated by HD in both radical scavenging and AChE inhibition assays, as well as in the enzyme inhibition assays. [ABSTRACT FROM AUTHOR]

Volatile compounds are important determinants affecting fruit flavor. Previous study has identified a bud mutant of 'Ehime 38' (Citrus reticulata) with different volatile profile. However, the volatile changes between WT and MT during fruit development and underlying mechanism remain elusive. In this study, a total of 35 volatile compounds were identified in the pulps of WT and MT at five developmental stages. Both varieties accumulated similar and the highest levels of volatiles at stage S1, and showed a downward trend as the fruit develops. However, the total volatile contents in the pulps of MT were 1.4--2.5 folds higher than those in WT at stages S2-S5, which was mainly due to the increase in the content of d-limonene. Transcriptomic and RT-qPCR analysis revealed that most genes in MEP pathway were positively correlated with the volatile contents, of which DXS1 might mainly contribute to the elevated volatiles accumulation in MT by increasing the flux into the MEP pathway. Moreover, temporal expression analysis indicated that these MEP pathway genes functioned at different developmental stages. This study provided comprehensive volatile metabolomics and transcriptomics characterizations of a citrus mutant during fruit development, which is valuable for fruit flavor improvement in citrus. [ABSTRACT FROM AUTHOR]

Fruit splitting is a prevalent physiological disorder that has a significant impact on Daisy mandarin fruit production, posing challenges to farmers in terms of productivity and economic viability. Despite its impact, no prior research on fruit splitting in Daisy mandarin has been conducted. This study aimed to assess the effect of fruit splitting on quality, morphological characteristics, biochemical composition and nutrient content in Daisy mandarin. In 2022, a comprehensive analysis was conducted on both split and healthy Daisy mandarin fruits, budded on Rough lemon rootstock, to investigate their morphological characteristics, biochemical characteristics, mineral content and cell wall components. Additionally, the study examined the activity of cell wall-degrading enzymes, such as peroxidase (POD), cellulase (Cx) and polygalacturonase (PG). The Results indicated that split fruits exhibited larger fruit size and weight and increased water content in both the fruits and peel compared to healthy fruits. However, split fruits had thinner peel thickness and lower peel content. The peels of split fruits also contained higher level of total soluble sugars, amino acids, and proline content. Furthermore, the peels of split fruits displayed much higher activity of cell wall-degrading enzymes than those of healthy fruits. The nutrient analysis of the split fruits revealed a decrease in boron, calcium and potassium content in the peel compared to healthy fruits. The study provides crucial insights into the mechanisms underlying fruit splitting, identifying biochemical and physiological differences between split and healthy fruits. These findings offer valuable information for developing strategies to mitigate fruit splitting, enhancing fruit quality and reducing economic losses for citrus growers. Future research should explore the genetic and environmental factors contributing to fruit splitting and investigate potential interventions to improve nutrient management and fruit integrity in Daisy mandarin cultivation. [ABSTRACT FROM AUTHOR]

Brown spot of citrus caused by Alternaria citri is one of the emerging threats to the successful production of citrus crops. The present study, conducted with a substantial sample size of 50 leaf samples for statistical reliability, aimed to determine the change in mineral content in citrus leaves after brown spot disease attack. Leaf samples from a diverse range of susceptible citrus varieties (Valentia late, Washington navel, and Kinnow) and resistant varieties (Citron, Eruka lemon, and Mayer lemon) were analyzed. Significant variations (p ≤ 0.05) in mineral contents were observed across reaction groups (inoculated and un-inoculated), types (resistant and susceptible), and varieties of citrus in response to infection of Alternaria citri. The analysis of variance showed significant changes in mineral levels of citrus leaves, including nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), zinc (Zn), sodium (Na), iron (Fe), and copper (Cu). The results indicate that the concentration of N and P differed by 6.63% and 1.44%, respectively, in resistant plants, while susceptible plants showed a difference of 6.07% and 1.19%. Moreover, resistant plants showed a higher concentrations of K, Ca, Mg, Zn, Na, Fe, and Cu at 8.40, 2.1, 1.83, 2.21, 1.58, 2.89, and 0.36 ppm respectively, compared to susceptible plants which showed concentrations of 5.99, 1.93, 1.47, 1.09, 1.24, 1.81, and 0.31 ppm respectively. Amounts of mineral contents were reduced in both resistant as well as susceptible plants of citrus after inoculation. Amount of N (8.56), P (1.87) % while K (10.74), Ca (2.71), Mg (2.62), Zn (2.20), Na (2.08), Fe (3.57) and Cu (0.20) ppm were recorded in un-inoculated group of citrus plants that reduced to 3.15 and 0.76% and 3.66, 1.40, 0.63,0.42, 0.74, 1.13 and 0.13 ppm in inoculated group respectively. It was accomplished that susceptible varieties contained lower ionic contents than resistant varieties. The higher concentrations of ionic contents in resistant citrus varieties build up the biochemical and physiological processes of the citrus plant, which help to restrict spread of pathogens. Further research could explore the interplay between mineral nutrition and disease resistance in citrus, potentially leading to the development of new disease-resistant varieties. [ABSTRACT FROM AUTHOR]

Key message: A lipofectamine-mediated transfection protocol for DNA-free genome editing of citrus protoplast cells using a Cas9/gRNA ribonucleoprotein (RNP) complex resulted in the production of transgene free genome edited citrus. [ABSTRACT FROM AUTHOR]

Aim: Diet, including foods and beverages, affects migraine. Conversely, the influence of migraine therapies on dietary habits is largely unknown. This study aimed at investigating the effects of triptan intake on foods and drinks consumed by adults with migraine with and/or without aura. Methods: An exploratory questionnaire‐based survey took place online between November 2022 and June 2023. Participants were recruited through advertisements shared on social media accounts (e.g., Facebook and Instagram) and seasonal newsletters of three Danish patient associations. In addition, posters and flyers in headache and pain centers at Danish hospitals and private neurological, pain, and physiotherapeutic clinics were utilized. Results: A total of 314 adults with migraine with and/or without aura completed the survey. Among the respondents, 236 individuals (75.2%) regularly used triptans to treat their migraines. Compared with non‐triptan users, individuals using triptans were characterized by significantly more foods and/or drinks triggering migraine (74.2% vs. 56.4%, p = 0.005). Alcoholic beverages and most specifically red wine were overreported as migraine triggers by triptan users (48.3% vs. 21.8%, p < 0.001). In the week preceding the survey, red wine was significantly less consumed by triptan users than non‐triptan users (92.4% vs. 76.9%, p < 0.001). Conclusions: Patients who regularly consume triptans report red wine most frequently as a migraine trigger. Triptan users are characterized by a lower consumption of red wine than non‐triptan users, suggesting that a regular triptan intake may promote an increased sensitivity to red wine‐induced migraine. [ABSTRACT FROM AUTHOR]

Daily meteorological data from 1981 to 2022 and citrus growth periods data were used in this paper. The daily mean temperature, daily maximum temperature and their duration were selected as indicators of heat stress in citrus to clarify the spatial distribution characteristic and temporal variation trend of heat stress during citrus growth periods. The spatial and temporal differences of heat stress in different growing periods of citrus were compared using a paired t-test. The results show that (1) the average frequency, times and intensity of heat stress during flowering-fruit expanding stage of citrus are 87.73%, 2.23times•y-1 and 5.28d•times -1, respectively. High-value areas are mainly concentrated in the southeast of Jiangxi province. The average frequency, times and intensity of heat stress during the fruit expanding-fruit coloring stage of citrus are 56.43%, 1.15times•y-1 and 2.74d•times -1, respectively. High-value areas are mainly in the northern and central parts of Jiangxi province. (2) The station ratios, times and intensity of heat stress during the flowering-fruit expanding stage of citrus show a decreasing trend, with an average decrease of 0.90 percent points, 0.02 times and 0.06 d•time -1 every 10 years, respectively. The station ratios, times and intensity of heat stress during fruit expanding-fruit coloring stage of citrus show an increasing trend, with an average increase of 6.80 percent points, 0.26times and 0.50d•times -1 every 10 years, respectively. (3) The paired t-test results show that, the frequency, times and intensity of heat stress during flowering-fruit expanding stage of citrus are significantly higher than that during fruit expanding-fruit coloring stage of citrus. However, the climate tendency of times and intensity of heat stress during flowering-fruit expanding stage of citrus are significantly lower than that during fruit expanding-fruit coloring stage of citrus. The flowering-fruit expanding stage of citrus in Jiangxi province is the most frequent period of heat stress. For now, it is necessary to strengthen citrus defenses against heat stress during the flowering-fruit expanding stage. In the future, we should improve the prevention of heat stress in citrus during the fruit expanding-fruit coloring stage. [ABSTRACT FROM AUTHOR]

Cryptosporidium parvum (C. parvum) is one of the most prevalent species infecting humans and animals. Currently, the only FDA-licensed drug to treat cryptosporidiosis is nitazoxanide (NTZ), with no efficacy in immunocompromised hosts. Citrus paradisi (C. paradisi) has demonstrated anti-protozoal activities. This study aimed to investigate the anti-cryptosporidiosis effect of C. paradisi peel extract, either alone or in mediating the green synthesis of chitosan silver nanoparticles (Cs/Ag NPs), compared to NTZ. Mice were sorted into nine different groups. The effectiveness of the treatments was evaluated using parasitology, histopathology, immunohistochemistry, and immunology. C. paradisi outperformed nitazoxanide regarding oocyst shedding (79% vs. 61%). The effectiveness of NTZ Cs/Ag NPs and Citrus Cs/Ag NPs was enhanced to 78% and 91%, respectively. The highest oocyst inhibition was obtained by combining NTZ and Citrus Cs/Ag NPs (96%). NF-κB, TNF-α, and Il-10 levels increased in response to infection and decreased in response to various treatments, with the highest reduction in the group treated with combined NTZ citrus Cs/Ag NPs. Combining C. paradisi with NTZ could have a synergistic effect, making it a potentially effective anti-cryptosporidiosis agent. Utilizing C. paradisi in the green synthesis of Cs/Ag NPs improves the therapeutic response and can be used to produce novel therapeutic antiparasitic drugs. [ABSTRACT FROM AUTHOR]

Background and aims: Ensuring adequate and balanced nutrient supply is crucial for enhancing citrus fruit quality. Some plants could modulate nutrient bioavailability in soil through the enhancement of root exudation. The study aimed to reveal how citrus change its root exudates metabolism profile to adapt to the soil with secondary nutrients and micronutrients deficiency. Methods: Citrus sinensis Osbeck cv. Newhall ×Poncirus trifoliate (L.) Raf grown in Ganzhou citrus orchards was used to evaluate the effect of soil applied and foliar sprayed secondary nutrients and micronutrients (Ca, Mg, B, Fe, Zn, Se) on the mineral elements concentration, external and intrinsic quality of citrus. The hydroponic experiment was conducted with Poncirus trifoliate (L.) Raf grown either in full nutrient solutions or in specific nutrient shortage conditions (Ca, Mg, B) for 45 days to obtain root exudate and perform untargeted metabolomic analysis (UHPLC-MS/MS). Results: Adequate supplementation of secondary nutrients and micronutrients effectively enhanced the nutritional value and intrinsic quality (TSS/TA) of citrus. 791 features were identified in citrus root exudates. Some metabolites was identified as root exudates for the first time, such as hecogenin, bergaptol and limonin. In the absence of secondary nutrients and micronutrients, citrus roots will secrete more substances related to plant disease resistance, nutrient acquisition and plant-microbial interactions, such as resveratrol, cinnamaldehyde, scopoletin, and phloretin. Conclusion: These findings highlight the value of secondary nutrients and micronutrients in regulating fruit quality and root exudates metabolism profile of citrus. It reveal the strategies of citrus to mitigate the nutrient deficiency in soils. [ABSTRACT FROM AUTHOR]

The European Commission requested the EFSA Panel on Plant Health to conduct a pest categorisation of Ceroplastes rubens Maskell (Hemiptera: Coccidae), following the commodity risk assessments of Acer palmatum plants grafted on A. davidii and Pinus parviflora bonsai plants grafted on P. thunbergii from China, in which C. rubens was identified as a pest of possible concern to the European Union (EU). The pest, which is commonly known as the pink, red or ruby wax scale, originates in Africa and is highly polyphagous attacking plants from more than 193 genera in 84 families. It has been present in Germany since 2010 in a single tropical glasshouse. It is known to attack primarily tropical and subtropical plants, but also other host plants commonly found in the EU, such as Malus sylvestris, Prunus spp., Pyrus spp. and ornamentals. It is considered an important pest of Citrus spp. The pink wax scale reproduces mainly parthenogenetically, and it has one or two generations per year. Fecundity ranges from 5 to 1178 eggs. Crawlers settle usually on young twigs and later stages are sessile. All life stages of C. rubens egest honeydew on which sooty mould grows. Host availability and climate suitability suggest that parts of the EU would be suitable for establishment. Plants for planting and cut branches provide the main pathways for entry. Crawlers could spread over short distances naturally through wind, animals, humans or machinery. C. rubens could be dispersed more rapidly and over long distances via infested plants for planting for trade. The introduction of C. rubens into the EU could lead to outbreaks causing damage to orchards, amenity ornamental trees and shrubs. Phytosanitary measures are available to inhibit the entry and spread of this species. C. rubens satisfies the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. [ABSTRACT FROM AUTHOR]

Achieving seedlessness in citrus varieties is one of the important objectives of citrus breeding. Male sterility associated with abnormal pollen development is an important factor in seedlessness. However, our understanding of the regulatory mechanism underlying the seedlessness phenotype in citrus is still limited. Here, we determined that the miR159a‐DUO1 module played an important role in regulating pollen development in citrus, which further indirectly modulated seed development and fruit size. Both the overexpression of csi‐miR159a and the knocking out of DUO1 in Hong Kong kumquat (Fortunella hindsii) resulted in small and seedless fruit phenotypes. Moreover, pollen was severely aborted in both transgenic lines, with arrested pollen mitotic I and abnormal pollen starch metabolism. Through additional cross‐pollination experiments, DUO1 was proven to be the key target gene for miR159a to regulate male sterility in citrus. Based on DNA affinity purification sequencing (DAP‐seq), RNA‐seq, and verified interaction assays, YUC2/YUC6, SS4 and STP8 were identified as downstream target genes of DUO1, those were all positively regulated by DUO1. In transgenic F. hindsii lines, the miR159a‐DUO1 module down‐regulated the expression of YUC2/YUC6, which decreased indoleacetic acid (IAA) levels and modulated auxin signaling to repress pollen mitotic I. The miR159a‐DUO1 module reduced the expression of the starch synthesis gene SS4 and sugar transport gene STP8 to disrupt starch metabolism in pollen. Overall, this work reveals a new mechanism by which the miR159a‐DUO1 module regulates pollen development and elucidates the molecular regulatory network underlying male sterility in citrus. [ABSTRACT FROM AUTHOR]

Citrus peels are rich in flavonoids, and some valuable flavonoids with health benefits, such as polymethoxyflavones (PMFs), are found almost exclusively in citrus peels. While the peels usually regarded as by-product, leading to source waste. As a traditional method, drying is helpful to increase added-value of peels which can be used as medicine. However, the variations in variety and quantity of flavonoids during drying processes of citrus peel remain unknown. In this study, Guanxi honey pomelo peel investigated the effect of different drying methods on flavonoids content in citrus peels. Five drying techniques, namely, freeze-drying (FD) and hot air drying (HAD) at 30 °C, 50 °C, 70 °C and 90 °C were used employed for drying the pomelo peels and HPLC-Q-TOF-MS analysis identified 39 flavonoids changes in flavonoids across samples. FD proved to better preserve most glycosidic flavonoids. Flavonoid aglycones could be better preserved in samples of HAD at 30 ℃, 50 ℃ HAD and 90 ℃ HAD. Specifically, HAD at 30 ℃ and 50 ℃ HAD is beneficial for obtaining more valued polymethoxyflavones such as 5-hydroxy-6,7,4′-trimethoxyflavone, 5,7,8,4′-tetramethoxyflavone and 3,5,6,7,8,3′,4′-heptamethoxyflavone. The 90℃ HAD resulted in the highest content of naringenin and 5,7,8,4′-tetramethoxyflavanone. This study demonstrated the transformation characteristics of flavonoids in pomelo peel under varying drying conditions, providing benefits for comprehensive utilization of pomelo peel in extracting valued-added flavonoids. [ABSTRACT FROM AUTHOR]

Citrus trifoliate fruit (also known as Trifoliate orange) is one of the commercially-cultivated Citrus genus of plants belonging to the Rutaceae family. It has been traditionally-utilized in treatment of neurodegenerative disorders. However, the scientific evidence verifying this utilization needs further elucidation. Characterization of the bioactive constituents of C. trifoliata L. fruits extract and evaluating its effect on Parkinson's disease (PD) model. Rats were classified into 5 groups; control, PD, PD-treated by L-dopa/Carpidopa and PD-treated by oral Citrus trifoliata L. fruits extract (50 and 100 mg/kg). Deterioration in brain functions was evaluated through an in vivo open field, grid and catalepsy tests. The study also assessed the striatal neurotransmitters, oxidative stress markers and histopathological changes. Citrus trifoliata L. fruit extract has revealed motor improvement comparable to L-dopa and carbidopa. It has also effectively-improved oxidative stress via reduction of striatal malondialdehyde & nitric oxide along with replenishment of the striatal glutathione and superoxide dismutase. The extract caused significant reduction of the striatal myeloperoxidase activity and restoration of dopamine, γ-amino butyric acid (GABA), and acetylcholinesterase. This effect was further confirmed by amelioration of neuronal apoptosis, microgliosis and peri-neuronal vacuolation. Metabolite profiling revealed 40 constituents, with flavonoids representing the main identified class. The neuro-protective effect of Citrus trifoliata extract was achieved through the antioxidant and anti-inflammatory activities of its flavonoids, particularly hesperidin and naringin. This neuro-protective effect was evident at the behavioral, histological and neurotransmitter levels. [ABSTRACT FROM AUTHOR]

Pest and diseases have seriously threatened to the yield and quality of citrus. This study aims to explore the effect of citrus diseases on SPAD value using identification model by near-infrared spectroscopy with chemometrics. Leaf spectra and physicochemical indexes were further determined to detect the citrus diseases. The NIR spectra of citrus leaves with normal, canker and emery derma were obtained to measure the physicochemical indices by portable NIR spectrometer. The spectrum analysis showed that there was a reflection peak in the leaves near 553 nm, indicating the reflection peak after the chlorophyll saturated the high-frequency absorption of light. The maximum reflection peak of normal leaves was about 0.21, whereas, the lowest was about 0.13 in the leaves with the sand skin disease. The reflectance of normal leaves was higher than that of diseased leaves at 750-900 nm. The reason was that the reflectance decreased to enlarge the leaf cell cavities under disease stress. The variance was analyzed for two physical and chemical indexes. There were significant differences in the SPAD value indexes of the three types of citrus leaves, while no significant difference was found in fresh quality indexes. A qualitative and quantitative model of citrus diseases was also established to clarify the relationship with leaf spectrum. According to the ratio of 2:1, 212 blades were randomly divided into two dataset with 145 samples in training set and 67 samples in verification set. The SPA and PCA were used to screen the spectral variables. 17 and 20 optimal variables were selected to combine the RF and LWPLS. The comparison showed that the best detection was achieved in the qualitative model of LWPLS for three types of disease leaves using 401 variables of the original spectrum, with the accuracy of 94.03%. While the low accuracy of 77.61% was found in the qualitative model of RF for three types of disease leaves using SPA screening 17 variables. The main reason was that a few sensitive variables were eliminated, although the characteristic variables represented the most information of citrus leaves. A numerical model was also constructed to further verify whether the leaf diseases affected the SPAD value of normal and diseased leaves. The best performance was achieved in the LWPLS model in the normal blade SPAD value analysis with 401 spectral variables as the input. The RMSEP of LWPLS quantitative model for normal, canker and emery was 4.46%, the model had better prediction accuracy for SPAD value of leaves, R² and RPD were 0.93 and 2.19, respectively. NIR spectroscopy with chemometrics was feasible to identify the citrus diseases on physicochemical indexes of leaves. The finding can provide an important reference for the real-time field detection of citrus diseases. [ABSTRACT FROM AUTHOR]

Salt stress is one of the main obstacles to citrus production in arid and semi-arid regions, limiting fruit production and quality, making it necessary to use tolerant genetic materials to improve the quality of citrus production in these regions. The objective of this work was to evaluate the fruit quality 'Tahiti' lime grafted onto different rootstocks grown under salt stress and to evaluate different storage days. Three 'Tahiti' lime genotypes, two electrical conductivity of irrigation water, and two storage time were studied. Salt stress increased the fruit quality of 'Tahiti' lime. Storage for 10 days increases ascorbic acid and soluble sugars, independent of genotype and salt stress, while all genotypes have desirable postharvest fruit quality characteristics. Genotypes 2 and 3 are promising to be cultivated in semi-arid regions, in addition to maintaining the fruit quality in conditions of salt stress. Therefore, grafting is a technique to increase the postharvest quality of 'Tahiti' lime grown under salt stress. [ABSTRACT FROM AUTHOR]

Spain is the leading exporter of fresh citrus for consumption. In order to adapt to market needs, it is key to analyze the attributes that most influence each variety, the time of ripening and the color of the fruit. In this way, the producer can select the right fruit for each moment of the season. The main objective was to evaluate the fruit quality of three interesting orange tree varieties for fresh consumption: "Washington Navel," "Navelate," and "Lanelate" sweet orange. To achieve this goal, sensory analysis was combined with instrumental analysis. In Washington Navel, the maturity index provided a positive contribution to overall liking. Both herbaceous and fruity aroma have a negative influence on the overall liking score. In Navelina, the color and aromas (herbaceous and fruity) played an important positive role in overall liking. The importance of this smell could be related to the freshness of the oranges. In contrast, the maturity index provided a negative contribution. Lanelate is the only variety in which vitamin C provided a positive contribution to overall liking. However, L* value showed a negative contribution. Therefore, there were clearly different characteristics among varieties that were detected. So far, different orange varieties have not been compared according to their maturity index and using sensory analysis. Descriptive analysis and the variables that influence overall liking are fundamental to adapt to consumer expectations. The results obtained would help to select the fruit with better acceptability in the market. [ABSTRACT FROM AUTHOR]

During the last decades, a huge body of evidence has been accumulated suggesting that citrus fruits and their constituents might have a role in preventing many diseases including oral disease. We aimed to map the existing evidence of the potential of Citrus aurantifolia essential oil as an antiplaque agent. Electronic databases (PUBMED, Google Scholar, and Scopus) were searched using the broad MeSH terms and keywords. Search terms included Citrus aurantifolia, lime peel, essential oil, and antiplaque. The last search was performed on October 15th, 2023. Only original articles evaluating the potential of lime peel essential oil in plaque-forming inhibition were included. Study selection and systematic review were carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Review (PRISMA- ScR) statement. Before the beginning of the review, the Authors defined a checklist for inclusion criteria, thus including articles that meet the following: (i) published on peer- reviewed scientific journals; (ii) Citrus aurantifolia; (iii) essential oil derived from Citrus aurantifolia peel; (iv) preclinical and clinical studies. Reviews, meta-analyses, conference abstracts, and book chapters were excluded. Four reviewers performed the extraction of articles. Out of 6430 records, 1980 were screened for titles and abstracts after the removal of duplicates, only 59 were considered to be potentially eligible for inclusion. Finally, only 4 articles were included. The result showed that Citrus aurantifolia peel essential oil indirectly prevents the formation of dental plaque by inhibiting the oral growth of bacteria initiating the formation of biofilms. [ABSTRACT FROM AUTHOR]

Excessive soil acidity negatively affects citrus growth and development worldwide. However, less information has been presented on its tolerance to low pH stress (LPS). Here, the way in which citrus plants respond to LPS was investigated at morphological, physiological and molecular levels. Under LPS, the root length and diameter were significantly decreased. The malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents and catalase (CAT) activity were significantly enhanced. LPS increased the root indole-3-acetic acid (IAA) and gibberellins (GAs) contents, and leaf chlorophyll content. Additionally, nutrient uptake was significantly affected by LPS. RNA-seq data revealed that a total of 1319 genes responded to LPS, of which 573 and 746 genes were up- and down-regulated, respectively. These differentially expressed genes (DEGs) were mainly linked to carbon metabolism, reactive oxygen species scavenging, nutrient uptake and transport, and hormone synthesis/signalling. Taken together, our data provided an essential foundation for future elucidation of the LPS tolerance of citrus plants. [ABSTRACT FROM AUTHOR]

Citrus is commercially propagated via grafting, which ensures trees have consistent fruit traits combined with favorable traits from the rootstock such as soil adaptability, vigor, and resistance to soil pathogens. Graft incompatibility can occur when the scion and rootstock are not able to form a permanent, healthy union. Understanding and preventing graft incompatibility is of great importance in the breeding of new fruit cultivars and in the choice of scion and rootstock by growers. The rootstock US-1283, a citrandarin generated from a cross of "Ninkat" mandarin (Citrus reticulata) and "Gotha Road" #6 trifoliate orange (Poncirus trifoliata), was released after years of field evaluation because of its superior productivity and good fruit quality on "Hamlin" sweet orange (C. sinensis) under Florida's growing conditions. Subsequently, it was observed that trees of "Bearss" lemon (C. limon) and "Valencia" sweet orange (C. sinensis) grafted onto US-1283 exhibited unhealthy growth near the graft union. The incompatibility manifested as stem grooving and necrosis underneath the bark on the rootstock side of the graft. Another citrandarin rootstock, US-812 (C. reticulata "Sunki" x P. trifoliata "Benecke"), is fully graft compatible with the same scions. Transcriptome analysis was performed on the vascular tissues above and below the graft union of US- 812 and US-1283 graft combinations with "Bearss" and "Valencia" to identify expression networks associated with incompatibility and help understand the processes and potential causes of incompatibility. Transcriptional reprogramming was stronger in the incompatible rootstock than in the grafted scions. Differentially expressed genes (DEGs) in US-1283, but not the scions, were associated with oxidative stress and plant defense, among others, similar to a pathogen-induced immune response localized to the rootstock; however, no pathogen infection was detected. Therefore, it is hypothesized that this response could have been triggered by signaling miscommunications between rootstock and scion either through (1) unknown molecules from the scion that were perceived as danger signals by the rootstock, (2) missing signals from the scion or missing receptors in the rootstock necessary for the formation of a healthy graft union, (3) the overall perception of the scion by the rootstock as non-self, or (4) a combination of the above. [ABSTRACT FROM AUTHOR]

In this study, Batem Pınarı, Interdonato, Meyer, and Ak Limon lemon cultivars were studied. Lemon peel's essential oils were obtained by two different methods (hydrodistillation and cold pressing) during four different harvest periods for each cultivar. Essential oil content, density, refractive index, optical activity, and composition were evaluated. The highest essential oil amount was found in the Interdonato cultivar (2.54%) and the lowest in Ak Limon (1.37%). The highest density value was 0.8471 g/mL (Ak Limon) and the lowest was 0.8423 g/mL (Meyer). Essential oil densities obtained by cold pressing were higher than those obtained by hydrodistillation. The highest refractive index values were determined for Batem Pınarı and Meyer (1.4747), and the lowest were determined for Ak Limon (1.4740). The refractive index values obtained by cold pressing were higher than those obtained by hydrodistillation. Optical activity values were found to be highest in Ak Limon and lowest in Batem Pınarı, and higher following hydrodistillation than cold pressing. The essential oil compositions of the samples showed significant differences depending on the cultivar and isolation method. Limonene, the highest component proportionally, composed 76.0%–89.0% of samples. The highest limonene content was determined for Ak Limon (88.7%), and the lowest for Batem Pınarı (76.7%). Limonene content did not change significantly between hydrodistillation (82.2%) and cold press (82.2%) isolation methods. Findings show that there is significant variation in quality parameters of lemon peel essential oils. [ABSTRACT FROM AUTHOR]

Citrus cultivars have various temperature needs for development and output at different times from flowering to harvesting, making climate one of the numerous factors that affect citrus' productivity and quality. In this study, the yield and heat unit requirements for several commercial citrus species over several seasons from 2010/2011 to 2021/2022 in Egypt were investigated. For this investigation, the time of flowering and the time of fruit harvesting were recorded. However, the required heat units from flowering to fruit harvesting were calculated based on daily records of air temperature, taking into account that all results below zero (negative results) are not used and all maximum air temperatures above 35.0 °C (≥35.1) are changed to 35.0 °C. In addition, the base air temperature of 13.0 °C was utilized for determining the required heat units. The results showed that in the experimental area, the overall mean of minimum air temperature, maximum air temperature, air relative humidity, and precipitation during the experimental periods had values of 15.2 °C, 28.70 °C, 59.3%, and 0.3 mm/day, respectively. Moreover, the lowest number of days required from flowering to fruit harvesting was observed to be 290.0 days for Fremont mandarin. Furthermore, the highest number of days required from flowering to fruit harvesting was observed to be 482 and 440 days, respectively, for Bearss Seedless lime and Valencia orange. Our study has highlighted a notable diversity among the investigated citrus cultivars, particularly highlighting specific cultivars that possess high yield. The cultivar that shows the greatest yield over the investigated seasons of the study was Valencia orange with 147.6 kg/tree. Moreover, the average values of the heat unit requirements for Washington Navel orange, Valencia orange, Murcott mandarin, Fremont mandarin, and Bearss Seedless lime were 3112.7, 3628.3, 3221.9, 3027.6, and 4398.4 °C day, respectively. This is the first report regarding the heat unit's determination for several citrus cultivars grown in Egypt, and we expect this research will provide a new awareness in accepting and discovering novel locations where citrus cultivars can be positively developed in Egypt. It will also prove to be a source of basic information for the development of the citrus crop model. [ABSTRACT FROM AUTHOR]

The comparative studies under laboratory conditions have been carried out to investigate the influence of different alternative host plants viz., bael [Aegle marmelos (L.)], curry leaves [Murraya koenigii (L.) Spreng.], ber (Zizyphus mauritiana Lam.) and lemon [Citrus limon (L.) Burm.f.] on biology and morphometrics of Lemon butterfly, Papilio demoleus (Linn.). The lemon is the most preferred host of P. demoleus used as a controlled experimental host plant. The variations in periods of larval, pupal and rate of emergence into adult have been recorded and found that the lemon was the most preferred host plant on which all the larval stages survived smoothly. The caterpillars when reared on alternative hosts showed an increase in average larval period. The average survival percent of larvae were reported highest on bael leaves, followed by curry leaves and ber leaves. Similar patterns of results were also recorded on the pupal period and rate of emergence with alternative hosts. The morphometric variations in weight, size and colour of caterpillars, pupae and adults were also measured and found in decreasing order of host preferences as lemon>bael>curry>ber. [ABSTRACT FROM AUTHOR]

MACROALGAE contain macro- and microelements, vitamins, amino acids, and phytohormones. These compounds contribute to the development of plants, making macroalgae highly promising as a biofertilizer for different crops. This study aimed to evaluate the potential of three local macroalgae available along the Mediterranean coast, Egypt, two of which are green algae (Ulva flexusoa and Enteromorpha intestinalis), and one of red algae (Griffithsia teges), on nutrition status and fruit quality of "Valencia" orange (Citrus sinensis, Osbeck). Aqueous extracts of the three macroalgae were prepared at 0 (control), 5, 10, and 15% concentrations and applied three times as a foliar application throughout the growing period. Results revealed that the macroalgae under investigation contain significant levels of various phytohormones, such as IAA, GA3 ABA, and CK; green algae contain the highest concentrations of GA3, whereas cytokine was observed only in G. tege. Macroalgae possess various amounts of essential macro- and microelements, containing Na > Ca >Mg >Mn in addition to Zn, CU, Fe, K, and P. Applying macroalgae extracts significantly affected the mineral composition of orange leaves and the chlorophyll content (presented as SPAD values). Green algae notably impacted fruit quality characteristics, including weight, length and width, juice volume, TSS, and peel color. However, no significant effect was detected on peel thickness or titratable acidity. We concluded that macroalgae extracts could be utilized as an eco-friendly biofertilizer, providing an alternative source for required nutrients in citrus and other fruit orchards. [ABSTRACT FROM AUTHOR]

To elucidate the characteristic taste distinctions between Shitougan and other citrus species, the primary taste-contributing substances in the juice sac, segment membrane, albedo and epicarp of 9 citrus varieties, including Shitougan citrus, were analyzed. Our findings revealed that the distribution patterns and concentrations of sugars, organic acids, flavonoids and triterpenoids in different tissues determined the taste profiles of various citrus species. The outer tissues of citrus fruits were identified as the principal sites for accumulation of sugars, organic acids, flavonoids, and triterpenes. Notably, amino acids, such as arginine (Arg), glutamate (Glu), histidine (His), alanine (Ala), aspartic acid (Asp), and proline (Pro), played a pivotal role in shaping the overall taste characteristics of these citrus species. In particular reference to Shitougan fruit - its main edible components comprising juice sacs and segment membranes exhibited relatively lower levels of sugars and organic acids; however higher contents of naringin and neohesperidin were detected in four other tissues within Shitougan fruit. Furthermore, principal component analysis (PCA) indicated that naringin and neohesperidin were primarily responsible for conferring a unique bitter taste to Shitougan fruit. These comprehensive results effectively bridge existing knowledge gaps pertaining to taste-contributing substances specific to Shitougan fruit while simultaneously providing a solid theoretical foundation for further exploration into molecular mechanisms underlying important flavor-imparting constituents within this variety. [ABSTRACT FROM AUTHOR]

Citrus aurantium fruit peel is a substantial source of polyphenols and flavonoids. An ultrasound-assisted procedure was used in this work for the extraction of these compounds from Citrus aurantium peels and additional steps of purification were carried out to yield flavonoid-enriched extract. Box–Behnken design was applied to optimize the ultrasound-assisted extraction (UAE) to obtain a flavonoid-enriched extract with the highest yields of polyphenols and flavonoids and the lowest yield of tannins. The optimal conditions of extraction were a solid-to-liquid ratio of 2.4 g/100 mL, an acetone concentration of 80%, and a sonication time of 34.7 min, yielding an extract with polyphenols yield of 33.76 ± 5.63 mg of gallic acid equivalent per g of dry matter (DM), flavonoids yield of 75.50 ± 5.59 mg of naringin equivalent per g of DM, and tannins yield of 19.85 ± 1.67 mg of tannic acid equivalent per g of DM. The optimized extract exhibited significantly higher yields of polyphenols and flavonoids along with a greater DPPH scavenging activity (IC50 = 30.7 ± 3.21 µg/mL) than the conventional extract prepared by maceration instead of UAE. These results prove the usefulness of UAE as an efficient and time-saving technique for the extraction of polyphenols and flavonoids from C. aurantium peel. [ABSTRACT FROM AUTHOR]

Citrus species have interest from many researchers for a long time, due to their wide distribution and the diversity in of their chemical composition. On the other hand, it is very important to study and to consistently improve extraction methods in order to increase their efficiency. Several extraction methods based on six citrus species peels have been studied by comparing total yields and concentrations of some bio-compounds (phenols, carbohydrates, proteins and pigments), as well as the antioxidant activity. Extraction methods significantly differed in their results, due to the differences in the mechanisms of action. Extraction by Reflux assisted method gave the highest yield, but it was not the best method in total phenolic content. Maceration method was better in total phenolic content, however Ultrasound method gave the highest value of carbohydrates content. Generally, Citrus species have a high content of phenols and carbohydrates, low proteins content and good polar pigments content. Regarding TLC profile, there is an increase in metabolites (number of spots) when assisted extraction methods were used, so extraction by assisted methods increases both quantity and quality of extraction yield. It was noted that water was a suitable solvent for phenols and carbohydrates extraction. Using agricultural waste such as citrus peels has many biological, environmental, industrial and so economical benefits. [ABSTRACT FROM AUTHOR]

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BACKGROUND: Levulinic acid (LA) is a multifunctional compound that is relevant to the economy of bio‐based chemical products. Citrus sinensis, the Valencia variety, is one of the world's most consumed citrus fruit varieties but suffers significant losses as a result of blue mold infestation. This research evaluated the inhibitory action of unpurified levulinic acid obtained from watermelon residues against the fungus Penicillium italicum, proposing a new use as a fungal inhibitor. RESULTS: LA was evaluated in in vitro tests and inhibited the mycelial growth of the fungus. In in vivo experiments with oranges, fungal proliferation in fruits was investigated by applying a crude mixture containing LA (43 mmol L−1) and formic acid (FA, 28 mmol L−1), and comparing the effects with FA alone and negative control (without inhibitory agent). The weight loss and disease incidence results decreased when LA was used as an inhibitory agent, with no negative impacts on fruit quality being observed. Its inhibitory effect was confirmed by determining the activities of the antioxidant enzymes catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD) and peroxidase (POD), where there was no increase in activities owing to inhibition of the fungus before its proliferation in the fruits. CONCLUSION: This study provides relevant data on the new use of raw LA as an antifungal agent, an effect still unexplored for this compound in recent literature, offering a practical and innovative solution to combat blue mold. © 2024 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

BACKGROUND: Mycorrhizal plants show enhanced resistance to biotic stresses, but few studies have addressed mycorrhiza‐induced resistance (MIR) against biotic challenges in woody plants, particularly citrus. Here we present a comparative study of two citrus species, Citrus aurantium, which is resistant to Tetranychus urticae, and Citrus reshni, which is highly susceptible to T. urticae. Although both mycorrhizal species are protected in locally infested leaves, they show very distinct responses to MIR. RESULTS: Previous studies have indicated that C. aurantium is insensitive to MIR in systemic tissues and MIR‐triggered antixenosis. Conversely, C. reshni is highly responsive to MIR which triggers local, systemic and indirect defense, and antixenosis against the pest. Transcriptional, hormonal and inhibition assays in C. reshni indicated the regulation of jasmonic acid (JA)‐ and abscisic acid‐dependent responses in MIR. The phytohormone jasmonic acid isoleucine (JA‐Ile) and the JA biosynthesis gene LOX2 are primed at early timepoints. Evidence indicates a metabolic flux from phenylpropanoids to specific flavones that are primed at 24 h post infestation (hpi). MIR also triggers the priming of naringenin in mycorrhizal C. reshni, which shows a strong correlation with several flavones and JA‐Ile that over‐accumulate in mycorrhizal plants. Treatment with an inhibitor of phenylpropanoid biosynthesis C4H enzyme impaired resistance and reduced the symbiosis, demonstrating that phenylpropanoids and derivatives mediate MIR in C. reshni. CONCLUSION: MIR's effectiveness is inversely correlated to basal immunity in different citrus species, and provides multifaceted protection against T. urticae in susceptible C. reshni, activating rapid local and systemic defenses that are mainly regulated by the accumulation of specific flavones and priming of JA‐dependent responses. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: The citrus red mite, Panonychus citri (McGregor) is a globally distributed agricultural pest. Of late, resistance to common acaricides has raised concerns that chemical control of P. citri is an inefficient means of control. Fluralaner, a highly toxic isoxazoline insecticide used to treat various ectoparasites, presents one potential alternative. However, little information has been reported about the effect of fluralaner on the citrus red mite. This study aims to evaluate the toxicity, sublethal and transgenerational effects of fluralaner on P. citri. RESULTS: In both laboratory and field populations of P. citri, we found fluralaner to be more toxic than conventional alternatives, including fenpropathrin, bifenazate, azocyclotin and chlorpyrifos. Interestingly, fluralaner proved more toxic to female adults than to the eggs of P. citri, with median lethal concentrations (LC50) of 2.446 and 122.7 mg L−1, respectively. Exposure to sublethal concentrations of fluralaner (LC10, LC20 and LC30) significantly reduced the fecundity and longevity of female adults P. citri individuals. Although concentrations of fluralaner applied to the parental female adults (F0) led to some changes in the developmental parameters, there were no significant changes in most of the life table parameters or population growth of the F1 generation. CONCLUSION: Our results indicate that fluralaner is highly toxic to P. citri, and a significant sublethal effect on F0 could suppress the population growth of P. citri, but not for F1. Fluralaner may be considered as a pesticide for the future management of the citrus red mite. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Background: Sweet oranges are a vital agricultural commodity, but they are susceptible to various pathogenic fungi that can cause significant economic losses. This study aimed to evaluate the antifungal activity of plant extracts against pathogenic fungi attacking sweet oranges in Jimma, Ethiopia. Materials and methods: Various plant extracts were obtained from locally available plant species and tested against selected pathogenic fungi using standard in vitro antifungal assays. The results revealed varying degrees of antifungal activity among the plant extracts, with some showing promising inhibitory effects against the targeted fungi. Statistical analysis indicated significant differences in antifungal efficacy among the tested extracts. Results: The study found that Penicilium spp., Aspergillus spp., Rhizopus spp., Mucor spp., and Fusarium spp, were the predominant fungal species. The study found that the extracts of Vernonia amygdalina, Ginger oficealae, and Pterolobium stalatam were effective in inhibiting mycelial growth against these pathogens. This suggests the use of these medicinal plants for the preservation and control of sweet orange fruit in most of the Ethiopian region. Conlusion: These findings suggest the potential of certain plant extracts as natural alternatives to synthetic fungicides for managing fungal diseases in sweet orange cultivation. Further research is needed to elucidate the mechanisms of action of these plant extracts and optimize their application in agricultural practices. This study contributes to the development of sustainable and eco-friendly strategies for plant disease management in the region.Article Highlights: The researchers identified various plant extracts that exhibit significant antifungal properties against fungi. The study conducted a comparative analysis between natural plant extracts and conventional chemical fungicides. Detailed phytochemical analysis identified the active compounds for the antifungal activity. [ABSTRACT FROM AUTHOR]

The main objective of this study is to analyze the drying kinetics of Citrus medica by using the freeze-drying method at various thicknesses (3, 5, and 7 mm) and cabin pressures (0.008, 0.010, and 0.012 mbar). Additionally, the study aims to evaluate the efficacy of an artificial neural network (ANN) in estimating crucial parameters like dimensionless mass loss ratio (MR), moisture content, and drying rate. Feedforward multilayer perceptron (MLP) neural network architecture was employed to model the freeze-drying process of Citrus medica. The ANN architecture was trained using a dataset covering various drying conditions and product characteristics. The training process, including hyperparameter optimization, is detailed and the performance of the ANN is evaluated using robust metrics such as RMSE and R2. As a result of comparing the experimental MR with the predicted MR of the ANN modeling created by considering various product thicknesses and cabin pressures, the R2 was found to be 0.998 and the RMSE was 0.010574. Additionally, color change, water activity, and effective moisture diffusivity were examined in this study. As a result of the experiments, the color change in freeze-dried Citrus medica fruits was between 6.9 ± 0.2 and 21.0 ± 0.6, water activity was between 0.4086 ± 0.0104 and 0.5925 ± 0.0064, effective moisture diffusivity was between 4.19 × 10 − 11 and 21.4 × 10 − 11 , respectively. In freeze-drying experiments conducted at various cabin pressures, it was observed that increasing the slice thickness of Citrus medica fruit resulted in longer drying times, higher water activity, greater color changes, and increased effective moisture diffusivity. By applying the experimental data to mathematical models and an ANN, the optimal process conditions were determined. The results of this study indicate that ANNs can potentially be applied to characterize the freeze-drying process of Citrus medica. [ABSTRACT FROM AUTHOR]

Citrus is one of the most important global fruit crops, with oranges accounting for more than half the total production. Citrus can be genetically engineered for improved traits, but the process is severely limited by shoot regeneration rates, especially in commercial varieties. Although standardizing a transformation protocol is difficult due to genotype and season dependencies, use of an optimal mineral nutrient basal culture medium increases the success of recovering transgenic Citrus cells. The purpose of this study is to improve shoot regeneration from juvenile tissue in multiple Citrus genotypes. Explants of 11 Citrus cultivars were regenerated in 21 published media to determine the optimal media for each genotype. The number of shoots from juvenile tissue were counted 90 days after the explants were first cultured. The type of basal medium strongly affected the rates of shoot regeneration from Citrus juvenile tissue, and the effectiveness was negatively correlated with the level of ammonium. For each Citrus grouping, optimized media formulations were determined, and potential improvements were predicted. In general, medium R7100 appeared to be the most effective for regeneration of the Citrus genotypes tested.Key Message: Results from this study indicate that basal medium strongly affected the rates of shoot regeneration from citrus juvenile tissue, and the effectiveness was negatively correlated with the level of ammonium present. [ABSTRACT FROM AUTHOR]

Background: Ichang papeda (Citrus ichangensis), a wild perennial plant of the Rutaceae family, is a cold-hardy plant. WRKY transcription factors are crucial regulators of plant growth and development as well as abiotic stress responses. However, the WRKY genes in C. ichangensis (CiWRKY) and their expression patterns under cold stress have not been thoroughly investigated, hindering our understanding of their role in cold tolerance. Results: In this study, a total of 52 CiWRKY genes identified in the genome of C. ichangensis were classified into three main groups and five subgroups based on phylogenetic analysis. Comprehensive analyses of motif features, conserved domains, and gene structures were performed. Segmental duplication plays a significant role in the CiWRKY gene family expansion. Cis-acting element analysis revealed the presence of various stress-responsive elements in the promoters of the majority of CiWRKYs. Gene ontology (GO) analysis and protein-protein interaction predictions indicate that the CiWRKYs exhibit crucial roles in regulation of both development and stress response. Expression profiling analysis demonstrates that 14 CiWRKYs were substantially induced under cold stress. Virus-induced gene silencing (VIGS) assay confirmed that CiWRKY31, one of the cold-induced WRKYs, functions positively in regulation of cold tolerance. Conclusion: Sequence and protein properties of CiWRKYs were systematically analyzed. Among the 52 CiWRKY genes 14 members exhibited cold-responsive expression patterns, and CiWRKY31 was verified to be a positive regulator of cold tolerance. These findings pave way for future investigations to understand the molecular functions of CiWRKYs in cold tolerance and contribute to unravelling WRKYs that may be used for engineering cold tolerance in citrus. [ABSTRACT FROM AUTHOR]

Huanglongbing (HLB) is caused by “Candidatus Liberibacter asiaticus” and is spread by citrus psyllids. It is a highly damaging and infectious disease of citrus for which there is no reliable treatment. Timely detection and removal of diseased trees is an effective strategy to control HLB. Various citrus cultivars infected with HLB exhibit distinct symptoms, posing a challenge to generalize HLB detection methods across multiple cultivars. Volatile organic compounds (VOCs) in HLB‐infected leaves from cultivars grown in different regions were comprehensively analysed by gas chromatography–mass spectrometry (GC‐MS) and gas chromatography‐ion mobility spectrometry (GC‐IMS), aiming to establish a new generalized HLB detection method applicable to a range of citrus cultivars. The changes in VOCs were analysed in leaves of four citrus cultivars after infection with HLB. The results showed that there was a similar response to HLB infection in different citrus cultivars, and this response was reflected in both the concentration and type of VOCs. By combining GC‐MS and GC‐IMS with orthogonal partial least squares discriminant analysis (OPLS‐DA) model, the accurate identification of the HLB infection status of different citrus cultivars was achieved, with the prediction indices reaching 0.994 for GC‐MS and 0.972 for GC‐IMS. In addition, 27 compounds were identified that were significantly different between citrus cultivars affected by HLB and healthy plants. This study provides valuable insights into the changes in VOCs in citrus cultivars after HLB infection and lays the theoretical foundation for VOC‐based HLB detection strategies. [ABSTRACT FROM AUTHOR]

Anthracnose in citrus is a severe disease caused by Colletotrichum species. Synthetic fungicides have been used to combat this citrus disease; however, they may have adverse health effects on humans and cause harmful environmental impacts. During a search for environmentally friendly fungicides, we successfully prepared organic copper (copper (II) oleate) nanoparticles by using natural chitosan polymer as a coating agent and stabilizer and by combining an exchange reaction and in situ coating method. Organic copper nanoparticles coated with chitosan polymer (Cu‐oleate@CS NPs) with Cu contents ranged from 5.0 to 6.0 % by weight. The nanoparticles have an average particle size ranging from 50 nm to 60 nm (TEM), covered by a layer of polymer with a thickness of about 10 to 12 nm. The analytical results of zeta potential and dynamic solution size showed that the nanoparticles are uniformly dispersed (90–120 nm by DLS), with high stability (zeta potential=−61.7 mV) and low cytoxicity to Vero healthy cell line. Cu‐oleate@CS NPs significantly inhibited the mycelial growth of C. gloeosporioides in vitro at 500 and 1000 μg/mL. In field trials, the best antifungal efficacy of Cu‐oleate@CS NPs against citrus anthracnose on orange plants was found at a spray concentration of 0.33 % with a disease control efficacy of 54.18 % at 14 days after the second spraying. Our study results demonstrated a novel preparation of Cu‐oleate@CS NPs and suggested that it could be used as a promising nanoformulation to control citrus anthracnose in vitro and in vivo. [ABSTRACT FROM AUTHOR]

Introduction: Fingered citron slices possess significant nutritional value and economic advantages as herbal products that are experiencing increasing demand. The grading of fingered citron slices plays a crucial role in the marketing strategy to maximize profits. However, due to the limited adoption of standardization practices and the decentralized structure of producers and distributors, the grading process of fingered citron slices requires substantial manpower and lead to a reduction in profitability. In order to provide authoritative, rapid and accurate grading standards for the market of fingered citron slices, this paper proposes a grading detection model for fingered citron slices based on improved YOLOv8n. Methods: Firstly, we obtained the raw materials of fingered citron slices from a dealer of Sichuan fingered citron origin in Shimian County, Ya'an City, Sichuan Province, China. Subsequently, high-resolution fingered citron slices images were taken using an experimental bench, and the dataset for grading detection of fingered citron slices was formed after manual screening and labelling. Based on this dataset, we chose YOLOv8n as the base model, and then replaced the YOLOv8n backbone structure with the Fasternet main module to improve the computational efficiency in the feature extraction process. Then we redesigned the PAN-FPN structure used in the original model with BiFPN structure to make full use of the high-resolution features to extend the sensory field of the model while balancing the computation amount and model volume, and finally we get the improved target detection algorithm YOLOv8-FCS. Results: The findings from the experiments indicated that this approach surpassed the conventional RT-DETR, Faster R-CNN, SSD300 and YOLOv8n models in most evaluation indicators. The experimental results show that the grading accuracy of the YOLOv8-FCS model reaches 98.1%, and the model size is only 6.4 M, and the FPS is 130.3. Discussion: The results suggest that our model offers both rapid and precise grading for fingered citron slices, holding significant practical value for promoting the advancement of automated grading systems tailored to fingered citron slices. [ABSTRACT FROM AUTHOR]

Citrus fruits are extensively cultivated fruits with high nutritional value. The identification of distinct ripeness stages in citrus fruits plays a crucial role in guiding the planning of harvesting paths for citrus-picking robots and facilitating yield estimations in orchards. However, challenges arise in the identification of citrus fruit ripeness due to the similarity in color between green unripe citrus fruits and tree leaves, leading to an omission in identification. Additionally, the resemblance between partially ripe, orange-green interspersed fruits and fully ripe fruits poses a risk of misidentification, further complicating the identification of citrus fruit ripeness. This study proposed the YOLO-CIT (You Only Look Once-Citrus) model and integrated an innovative R-LBP (Roughness-Local Binary Pattern) method to accurately identify citrus fruits at distinct ripeness stages. The R-LBP algorithm, an extension of the LBP algorithm, enhances the texture features of citrus fruits at distinct ripeness stages by calculating the coefficient of variation in grayscale values of pixels within a certain range in different directions around the target pixel. The C3 model embedded by the CBAM (Convolutional Block Attention Module) replaced the original backbone network of the YOLOv5s model to form the backbone of the YOLO-CIT model. Instead of traditional convolution, Ghostconv is utilized by the neck network of the YOLO-CIT model. The fruit segment of citrus in the original citrus images processed by the R-LBP algorithm is combined with the background segment of the citrus images after grayscale processing to construct synthetic images, which are subsequently added to the training dataset. The experiment showed that the R-LBP algorithm is capable of amplifying the texture features among citrus fruits at distinct ripeness stages. The YOLO-CIT model combined with the R-LBP algorithm has a Precision of 88.13%, a Recall of 93.16%, an F1 score of 90.89, a mAP@0.5 of 85.88%, and 6.1ms of average detection speed for citrus fruit ripeness identification in complex environments. The model demonstrates the capability to accurately and swiftly identify citrus fruits at distinct ripeness stages in realworld environments, effectively guiding the determination of picking targets and path planning for harvesting robots. [ABSTRACT FROM AUTHOR]

Crop phenotyping data collection is the basis for precision agriculture and smart decision-making applications. Accurately obtaining the canopy volume of citrus trees is crucial for yield prediction, precise fertilization and cultivation management. To this end, we developed a dynamic slicing and reconstruction (DR) algorithm based on 3D point clouds. The algorithm dynamically slices nearby slices based on their proportional area change and density difference; for each slice point cloud, the average distance of each point from others is taken as the initial α value for the AS algorithm. This value is iteratively summed until it reconstructs the complete shape, allowing the volume of each slice shape to be determined. Compared with six point cloud-based reconstruction algorithms, the DR approach achieved the best results in removing perforations and lacunae (0.84) and exhibited volumetric consistency (1.53) that closely aligned with the growth pattern of citrus trees. The DR algorithm effectively addresses the challenges of adapting the thickness and number of canopy point cloud slices to the shape and size of the canopy in the ASBS and CHBS algorithms, as well as overcoming inaccuracies and incompleteness in reconstructed canopy models caused by limitations in capturing detailed features using the PCH algorithm. It offers improved adaptive ability, finer volume computations, better noise reduction, and anomaly removal. [ABSTRACT FROM AUTHOR]

Materials based on highly reactive α-tricalcium phosphate (α-TCP) powder were developed and evaluated. Furthermore, the impact of different polymeric additives, such as citrus pectin or polyacrylamide (PAAM) modified with sago starch, neem flower, or rambutan peel, on the physiochemical and biological properties of the developed materials was assessed. The addition of modified PAAM shortened the setting process of bone cements and decreased their compressive strength. On the other hand, the addition of citrus pectin significantly enhanced the mechanical strength of the material from 4.46 to 7.15 MPa. The improved mechanical properties of the bone cement containing citrus pectin were attributed to the better homogenization of cementitious pastes and pectin cross-linking by Ca2+ ions. In vitro tests performed on L929 cells showed that 10% extracts from α-TCP cements modified with pectin are more cytocompatible than control cements without any additives. Cements containing PAAM with plant-derived modifiers show some degree of cytotoxicity for the highly concentrated 10% extracts, but for diluted extracts, cytotoxicity was reduced, as shown by a resazurin reduction test and live/dead staining. All the developed bone substitutes exhibited in vitro bioactivity, making them promising candidates for further biological studies. This research underscores the advantageous properties of the obtained biomaterials and paves the way for subsequent more advanced in vitro and in vivo investigations. [ABSTRACT FROM AUTHOR]

The flavonoids in citrus fruits are crucial physiological regulators and natural bioactive products of high pharmaceutical value. Melatonin is a pleiotropic hormone that can regulate plant morphogenesis and stress resistance and alter the accumulation of flavonoids in these processes. However, the direct effect of melatonin on citrus flavonoids remains unclear. In this study, nontargeted metabolomics and transcriptomics were utilized to reveal how exogenous melatonin affects flavonoid biosynthesis in "Bingtangcheng" citrus fruits. The melatonin treatment at 0.1 mmol L−1 significantly increased the contents of seven polymethoxylated flavones (PMFs) and up-regulated a series of flavonoid pathway genes, including 4CL (4-coumaroyl CoA ligase), FNS (flavone synthase), and FHs (flavonoid hydroxylases). Meanwhile, CHS (chalcone synthase) was down-regulated, causing a decrease in the content of most flavonoid glycosides. Pearson correlation analysis obtained 21 transcription factors co-expressed with differentially accumulated flavonoids, among which the AP2/EREBP members were the most numerous. Additionally, circadian rhythm and photosynthesis pathways were enriched in the DEG (differentially expressed gene) analysis, suggesting that melatonin might also mediate changes in the flavonoid biosynthesis pathway by affecting the fruit's circadian rhythm. These results provide valuable information for further exploration of the molecular mechanisms through which melatonin regulates citrus fruit metabolism. [ABSTRACT FROM AUTHOR]

Citrus peel, as an effective component of citrus by-products, contains a large number of natural active components, including pectin, vitamins, dietary fiber, essential oil, phenolic compounds, flavonoids, and so on. With the development of the circular economy, citrus peel has attracted extensive concern in the food industry. The exploitation of citrus peel would assist in excavating potential properties and alleviating the environmental burden. Polymethoxyflavones (PMFs) exist almost in citrus peel, which have remarkable biological activities including antioxidant, anti-inflammatory, anti-cancer, and anti-obesity. Therefore, PMFs from citrus peel have the potential to develop as dietary supplements in the near future. Collectively, it is essential to take action to optimize the extraction conditions of PMFs and make the most of the extracts. This review mainly compiles several extraction methods and bioactivities of PMFs from citrus peel and introduces different applications including food processing, pharmaceutical industry, and plant rhizosphere to develop better utilization of citrus PMFs. Polymethoxyflavones (PMFs) represent sustainable bioactive compounds that profit for circular economy. Valorization of citrus peel PMFs will bring value-added environmental benefits. Novel techniques improve property and extraction efficiency of PMFs. PMFs obtained from citrus peel could be applied to tea or bakery food processing and pharmaceutical industry. [ABSTRACT FROM AUTHOR]

The vector-transmitted Citrus Greening (CG) disease, also called Huanglongbing, is one of the most destructive diseases of citrus. Since no measures for directly controlling this disease are available at present, current disease management integrates several measures, such as vector control, the use of disease-free trees, the removal of diseased trees, etc. The most essential issue in integrated management is how CG-infected trees can be detected efficiently. For CG detection, digital image analyses using deep learning algorithms have attracted much interest from both researchers and growers. Models using transfer learning with the Faster R-CNN architecture were constructed and compared with two pre-trained Convolutional Neural Network (CNN) models, VGGNet and ResNet. Their efficiency was examined by integrating their feature extraction capabilities into the Convolution Block Attention Module (CBAM) to create VGGNet+CBAM and ResNet+CBAM variants. ResNet models performed best. Moreover, the integration of CBAM notably improved CG disease detection precision and the overall performance of the models. Efficient models with transfer learning using Faster R-CNN were loaded on web applications to facilitate access for real-time diagnosis by farmers via the deployment of in-field images. The practical ability of the applications to detect CG disease is discussed. [ABSTRACT FROM AUTHOR]

Huyou (Citrus changshanensis) is a significant citrus species that originated in Zhejiang Province, China, where it is also primarily cultivated. It is valued for its distinctive flavor and notable health benefits, owing to its high content of bioactive compounds like naringin and limonin. However, the absence of a high quality reference genome has limited the exploration of these health-promoting compounds in Huyou and hindered research into the mechanisms behind its medicinal properties. In this study, we present a phased chromosome-level genome assembly of Huyou. By combining PacBio and Hi-C sequencing, we generated a primary genome assembly and two haplotypes, comprising nine pseudo-chromosomes, with sizes of 339.91 Mb, 323.51 Mb, and 311.89 Mb, respectively. By integrating transcriptome data and annotations of homologous species, we identified a total of 29,775 protein-coding genes in the genome of Huyou. Additionally, we detected lots of structural variants between the two haplotypes. This represents the first reference genome of Huyou, providing a valuable resource for future studies on its agricultural characteristics and medicinal applications. [ABSTRACT FROM AUTHOR]

Phytosanitary monitoring conducted in 2023 across citrus plantations in the Adjara-Guria region in Georgia indicated an unfavorable situation. The damage caused by mites was particularly severe, with the citrus rusty (silver) mite (Phyllocoptruta oleivorus Ashm.) and the citrus red mite (Panonychus citri McGregor) observed at the highest intensity (3 points). Both old and younger plants were found to be infested by these pests. A widespread distribution of scale insects was also recorded, including the citrus rust mite (P. oleivorus Ashm.), citrus red mite (P. citri McGregor), yellow scale (Aonidiella citrina Coq.), citrus mussel scale (Lepidella beckii Newman), Japanese maple scale (Lopholeucaspis japonica Cockerell), tortoise wax scale (Ceroplastes japonicus Green), wax scale (Ceroplastes sinensis Del Guercio), brown soft scale (Coccus hesperidum L.), cottony camellia scale (Pulvinaria floccifera Westwood), citrus cottony scale (Pulvinaria aurantii Cockerell), citrus whitefly (Dialeurodes citri Ashm.), citrus blackfly (Aleurocanthus woglumi Ashby), woolly whitefly (Aleurothrixus floccosus Maskell), and citrus spiny whitefly (Aleurocanthus spiniferus Quaintance). The citrus blackfly, citrus spiny whitefly, and woolly whitefly were identified as particularly problematic. In Georgia, they are registered as quarantine pests. [ABSTRACT FROM AUTHOR]

Plants face a wide range of biotic and abiotic stress conditions, which are further intensified by climate change. Among these stressors, increased irradiation in terms of intensity and wavelength range can lead to detrimental effects, such as chlorophyll degradation, destruction of the PSII reaction center, generation of ROS, alterations to plant metabolism, and even plant death.Here, we investigated the responses of two citrus genotypes, Citrus macrophylla (CM), and Troyer citrange (TC) to UV‐B light‐induced stress, by growing plants of both genotypes under control and UV‐B stress conditions for 5 days to evaluate their tolerance mechanisms.TC seedlings had higher sensitivity to UV‐B light than CM seedlings, as they showed more damage and increased levels of oxidative harm (indicated by the accumulation of MDA). In contrast, CM seedlings exhibited specific adaptive mechanisms, including accumulation of higher levels of proline under stressful conditions, and enhanced antioxidant capacity, as evidenced by increased ascorbate peroxidase activity and upregulation of the CsAPX2 gene. Phytohormone accumulation patterns were similar in both genotypes, with a decrease in ABA content in response to UV‐B light. Furthermore, expression of genes involved in light perception and response was specifically affected in the tolerant CM seedlings, which exhibited higher expression of CsHYH/CsHY5 and CsRUP1‐2 genes.These findings underscore the importance of the antioxidant system in citrus plants subjected to UV‐B light‐induced stress and suggest that CsHYH/CsHY5 and CsRUP1‐2 could be considered genes associated with tolerance to such challenging conditions. [ABSTRACT FROM AUTHOR]

Citrus amblycarpa possesses various pharmacological activities, such as antioxidant, anticancer, antitumor, hepatoprotective, anti-inflammatory, antidiabetic, antiviral, antibacterial, and antifungal. The main active compounds in C. amblycarpa (including gamma (γ)-aminobutyric acid [GABA], hesperidin, naringin, neoeriocitrin, poncirin, quercetin, and rutin) show potential to interact with the inflammatory proteins in hepatic steatosis (such as nuclear factor kappa beta [NF-κB], tumor necrosis alpha [TNF-alpha], interleukin-6 [IL-6], c-Jun NH2-terminal kinase [JNK], and adiponectin). Molecular docking simulations were performed using Swiss Dock (http://www.swissdock.ch/), and analysis and visualization were conducted using Discovery Studio 4.1. Rutin, poncirin, hesperidin, and neoeriocitrin exhibit high affinities to NF-κB, TNF-alpha, IL-6, and adiponectin proteins, respectively. Similar to curcumin--adiponectin complex interaction, neoeriocitrin--adiponectin interaction involves GLY 223, PRO41, and VAL93 residues. Thus, the most potent inhibitor of hepatic sterosis marker was neoeriocitrin. [ABSTRACT FROM AUTHOR]

Background: Data from mechanistic studies suggest flavonoids may benefit glucose metabolism, but their associations with type 2 diabetes (T2D) remain unclear. This study examined the prospective associations of dietary intake of total, classes, and individual flavonoids, as well as their source foods, with T2D in the CArdioVascular disease Association Study (CAVAS). Methods: A total of 16,666 Korean men and women were enrolled at baseline, and 953 were newly diagnosed with T2D over a median follow-up of 5.96 years. Intake of flavonoids was cumulatively averaged using all food frequency questionnaires before the censoring events. A Poisson regression model was used to estimate incidence rate ratios (IRRs) and 95% confidence intervals (CIs). Results: Women with higher total flavonoid, flavonol, isoflavone, and proanthocyanidin intake had a lower risk of T2D (fourth vs. first quartile, IRR 0.62; 95% CI 0.44–0.89; P for linearity and non-linearity < 0.05 for total flavonoids), while in men, flavanones, anthocyanins, and proanthocyanidins, but not total flavonoids, were inversely associated with T2D risk (all P interaction for sex > 0.05). The key source foods contributing to flavonoid intake were also different between men and women, except for apples: tangerines and strawberries in men and green leafy vegetables and soy products in women. Conclusions: A higher intake of total flavonoids, particularly from vegetables, soybeans, and apples, may be associated with lower risk of T2D in women. However, flavonoids from fruits, rather than total flavonoids, may be inversely associated in men. The association between flavonoid intake and the risk of T2D may be contingent upon the dietary sources of flavonoids consumed. [ABSTRACT FROM AUTHOR]