Project description:Citrus (Citrus reticulate Blanco) is one of the most commonly consumed and widely distributed fruit in the world, which is possessing extensive bioactivities. Present study aimed to fully understand the flavonoids compositions, antioxidant capacities and in vitro anticancer abilities of different citrus resources. Citrus fruits of 35 varieties belonging to 5 types (pummelos, oranges, tangerines, mandarins and hybrids) were collected. Combining li quid chromatography combined with electrospray ionization mass spectrometry (LC-ESI-MS/MS) and ultra-performance liquid chromatography combined with diode array detector (UPLC-DAD), a total of 39 flavonoid compounds were identified, including 4 flavones, 9 flavanones and 26 polymethoxylated flavonoids (PMFs). Each citrus fruit was examined and compared by 4 parts, flavedo, albedo, segment membrane and juice sacs. The juice sacs had the lowest total phenolics, following by the segment membrane. Four antioxidant traits including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC) and cupric reducing antioxidant capacity (CUPRAC) were applied for the antioxidant capacities evaluation. Three gastric cancer cell lines, SGC-7901, BGC-823 and AGS were applied for the cytotoxicity evaluation. According to the results of correlation analysis, phenolics compounds might be the main contributor to the antioxidant activity of citrus extracts, while PMFs existing only in the flavedo might be closely related to the gastric cancer cell line cytotoxicity of citrus extracts. The results of present study might provide a theoretical guidance for the utilization of citrus resources.
Project description:Five new: 21,23-dihydro-21-hydroxy-23-oxonomilin (1), 21,23-dihydro-23-methoxy-21-oxonomilin (2), 21,23-dihydro-21-hydroxy-23-oxonomilinic acid methyl ester (3), 21,23-dihydro-23-methoxy-21-oxolimonin (4), and 21,23-dihydro-21-oxolimonin (5), and seven known limonoids were isolated from peels of satsuma orange (Citrus reticulata). The isolated compounds were evaluated for their inhibitory effects on macrophage activation by an inhibitory assay of nitric oxide (NO) production. Among them, compound (2) exhibited NO inhibitory activity without cytotoxicity.
Project description:Flavonoids are a kind of essential substance for the human body because of their antioxidant properties and extremely high medicinal value. Citrus reticulata "Dahongpao" (DHP) is a special citrus variety that is rich in flavonoids, however little is known about its systematic flavonoids profile. In the present study, the presence of flavonoids in five important citrus varieties, including DHP, Citrus grandis Tomentosa (HZY), Citrus ichangensis Swingle (YCC), Citrus sinensis (L.) Osbeck (TC), and Citrus reticulata 'Buzhihuo' (BZH), was determined using a UPLC-ESI-MS/MS-based, widely targeted metabolome. Results showed that a total of 254 flavonoid metabolites (including 147 flavone, 39 flavonol, 21 flavanone, 24 anthocyanins, 8 isoflavone, and 15 polyphenol) were identified. The total flavonoid content of peels from DHP was the highest. DHP could be clearly separated from other samples through clustering analysis and principal component analysis (PCA). Further, 169 different flavonoid metabolites were observed between DHP peels and the other four citrus peels, and 26 down-regulated differential metabolites displayed important biological activities in DHP. At the same time, a unique flavonoid component, tricin 4'-O-syringyl alcohol, was only found in DHP, which could be used as a marker to distinguish between other varieties. This work might facilitate a better understanding of flavonoid metabolites between DHP peels and the other four citrus peels and provide a reference for its sufficient utilization in the future.
Project description:Penicillium digitatum is one of the most important pathogens known widely to cause postharvest losses of citrus. It is significant to explore its infection mechanism to improve the control technology of postharvest diseases of citrus. This research aimed to study the changes in gene expression of P. digitatum at its early stages of citrus infection by transcriptomics sequencing and bioinformatics analysis in order to explore the molecular mechanism of its infection. The results showed that genes associated with pathogenic factors, such as cell wall degrading enzymes, ethylene, organic acids, and effectors, were significantly up-regulated. Concurrently, genes related to anti-oxidation and iron transport were equally up-regulated at varying degrees. From this study, we demonstrated a simple blueprint for the infection mechanism of P. digitatum in Citrus reticulata Blanco, which provided a new direction for subsequent pathological research and paves the way for developing new control strategies.
Project description:Low temperature storage of citrus fruits are susceptible to chilling disorder symptoms that impact fruit quality. Understanding the molecular frame underlying the cold storage process will provide a basic guidance for practical control. We used Affymetrix Citrus GeneChip to examine the transcriptional changes in cold-stored Citrus reticulata Blanco cv. ‘Ponkan’ pulp tissue for three successive months.
Project description:Protoplast isolation is a stress-inducing process, during which a variety of physiological and molecular alterations take place. Such stress response affects the expression of totipotency of cultured protoplasts. MicroRNAs (miRNAs) play important roles in plant growth, development and stress responses. However, the underlying mechanism of miRNAs involved in the protoplast totipotency remains unclear. In this study, high-throughput sequencing technology was used to sequence two populations of small RNA from calli and callus-derived protoplasts in Citrus reticulata Blanco. A total of 67 known miRNAs from 35 families and 277 novel miRNAs were identified. Among these miRNAs, 18 known miRNAs and 64 novel miRNAs were identified by differentially expressed miRNAs (DEMs) analysis. The expression patterns of the eight DEMs were verified by qRT-PCR. Target prediction showed most targets of the miRNAs were transcription factors. The expression levels of half targets showed a negative correlation to those of the miRNAs. Furthermore, the physiological analysis showed high levels of antioxidant activities in isolated protoplasts. In short, our results indicated that miRNAs may play important roles in protoplast-isolation response.
Project description:Kinnow mandarin (Citrus reticulata Blanco) is a popular citrus crop of northwestern India and it occupies maximum fruit area in Punjab. However, citrus juice processing industry is still suffering from delayed bitterness problem caused mainly by limonoid aglycones such as limonin. In order to study citrus limonoid metabolism, limonoid glucosyltransferase (LGT) gene, which encodes a natural debittering enzyme, was isolated from the fruit tissues of Kinnow mandarin. After confirmation and characterization, its full-length gene sequence (1533 bp) was submitted to National Centre for Biotechnology Information. Citrus reticulata limonoid glucosyltransferase (CrLGT) occupies a position on an independent branch in the largest subgroup and is phylogenetically different from those in other mandarin species like C. unshiu, showing its uniqueness in several features. The transcript expression of CrLGT, evaluated in different tissues such as young leaf, flavedo, albedo, sac covering and seed of Kinnow mandarin during early (90 days after flowering (DAF)), mid (150-210 DAF) and late (240 DAF) fruit developmental stages using semi-quantitative method, showed the highest expression in flavedo. Thus, it was concluded that the isolated LGT gene has an effect on limonoid metabolic engineering in citrus. Overexpression of this gene can reduce the delayed bitterness problem in citrus juice and enhance the accumulation of specific glucosides that have anticancer effects.
Project description:Citrus reticulata Blanco 'Orah' is grown throughout southern China and provides enormous economic value. However, the agricultural industry has suffered substantial losses during recent years due to marbled fruit disease. The present study focuses on the soil bacterial communities associated with marbled fruit in 'Orah'. The agronomic traits and microbiomes of plants with normal and marbled fruit from three different orchards were compared. No significant differences were found in agronomic traits between the groups, except for higher fruit yields and higher quality of fruits in normal fruit group. Additionally, a total of 2,106,050 16S rRNA gene sequences were generated via the NovoSeq 6000. The alpha diversity index (including the Shannon and Simpson indices), Bray-Curtis similarity, and principal component analyses indicated no significant differences in microbiome diversity between normal and marbled fruit groups. For the healthy 'Orah', the most abundant associated phyla were Bacteroidetes, Firmicutes, and Proteobacteria. In comparison, Burkholderiaceae and Acidobacteria were the most abundant taxa with the marbled fruit group. In addition, the family Xanthomonadaceae and the genus Candidatus Nitrosotalea were prevalent with this group. Analysis using the Kyoto Encyclopedia of Genes and Genomes pathways showed that several pathways related to metabolism significantly differed between the groups. Thus, the present study provides valuable information regarding soil bacterial communities associated with marbled fruit in 'Orah'.
Project description:Citrus Huanglongbing (HLB), the most destructive citrus disease, can be transmitted by psyllids and diseased budwoods. Although the final symptoms of the two main HLB transmission ways were similar and hard to distinguish, the host responses might be different. In this study, the global gene changes in leaves of ponkan (Citrus reticulata) mandarin trees following psyllid-transmission of HLB were analyzed at the early symptomatic stage (13 weeks post inoculation, wpi) and late symptomatic stage (26 wpi) using digital gene expression (DGE) profiling. At 13 wpi, 2452 genes were downregulated while only 604 genes were upregulated in HLB infected ponkan leaves but no pathway enrichment was identified. Gene function analysis showed impairment in defense at the early stage of infection. At late stage of 26 wpi, however, differentially expressed genes (DEGs) involved in carbohydrate metabolism, plant defense, hormone signaling, secondary metabolism, transcription regulation were overwhelmingly upregulated, indicating that the defense reactions were eventually activated. The results indicated that HLB bacterial infection significantly influenced ponkan gene expression, and a delayed response of the host to the fast growing bacteria might be responsible for its failure in fighting against the bacteria.