Citrus exosome-modified exogenous dsRNA delivery reduces plant pathogen resistance and mycotoxin production.

Plant-derived exosome-like nanoparticles (PENs) are crucial for intercellular communication. However, PEN-based transport of pathogenic fungal genes remains unclear. This study isolated and purified PENs from lane late navel orange citrus juice by following the sucrose gradient ultracentrifugation technique. Citrus PENs were round and oval-shaped with an average size of 154.5 ± 1.9 nm. Electroporation-based exogenous dsRNA to PENs loading efficiency remained at 6.0 %. Laser confocal microscopy was employed to investigate citrus PEN uptake by fungal spores. dsCrcB loaded PENs inhibited the CrcB gene expression in spores to alleviate Penicillium italicum resistance against prochloraz fungicide, which promoted resistant strains' mortality by 10-fold. Moreover, dsFUM21-loaded PENs suppressed the FUM21 gene expression in spores, which significantly reduced FB1 production in Fusarium proliferatum. These findings suggest that citrus PENs could potentially serve as nano-carriers to counter fungicide resistance and mycotoxin production in pathogenic plant fungi.

Sustainable utilization of fruit and vegetable waste bioresources for bioplastics production.

Nowadays, rapidly increasing production, use and disposable of plastic products has become one of the utmost environmental issues. Our current circumstances in which the food supply chain is demonstrated as containing plastic particles and other plastic-based impurities, represents a significant health risk to humans, animals, and environmental alike. According to this point of view, biodegradable plastic material aims to produce a more sustainable and greener world with a lower ecological impact. Bioplastics are being investigated as an environmentally friendly candidate to address this problem and hence global bioplastic production has seen significant growth and expansion in recent years. This article focuses on a few critical issues that must be addressed for bioplastic production to become commercially viable. Although the reduction of fruit and vegetable waste biomass has an apparent value in terms of environmental benefits and sustainability, commercial success at industrial scale has remained flat. This is due to various factors, including biomass feedstocks, pretreatment technologies, enzymatic hydrolysis, and scale-up issues in the industry, all of which contribute to high capital and operating costs. This review paper summarizes the global overview of bioplastics derived from fruit and vegetable waste biomass. Furthermore, economic and technical challenges associated with industrialization and diverse applications of bioplastics in biomedical, agricultural, and food-packaging fields due to their excellent biocompatibility properties are reviewed.HighlightsReview of the diverse types and characteristics of sustainability of biobased plasticsImproved pretreatment technologies can develop to enhance greater yieldEnzyme hydrolysis process used for bioplastic extraction & hasten industrial scale-upFocus on technical challenges facing commercialized the bioplasticsDetailed discussion on the application for sustainability of biodegradable plastics.

Involvement of miRNAs-mediated senescence and salicylic acid defense in postharvest litchi downy blight.

Litchi downy blight, caused by Peronophythora litchii, results in decline of market value of litchi fruit. In this study, roles of microRNAs (miRNAs) in regulating litchi fruit response to P. litchii infection was investigated. Results showed that P. litchii infection decreased anthocyanin content while accelerating fruit senescence. Salicylic acid (SA) content was also altered by P. litchii infection. Meanwhile, expression levels of LcmiR159, LcmiR828, LcmiR160 and LcmiR167 were investigated using stem-loop real-time quantitative PCR (RT-qPCR). Then, we identified LcGAMYB, LcTT2, LcARF18 and LcARF8 as their target genes, respectively, based on RNA Ligase-Mediated (RLM)-5'-RACE, transient co-expression assay in Nicotiana benthamiana as well as expression change of target genes. Our results suggested that LcmiR159-LcGAMYB and LcmiR828-LcTT2 modules participated in litchi downy blight possibly through regulating fruit senescence while LcmiR160-LcARF18 and LcmiR167-LcARF8 through SA-mediated defense response. This study provides new knowledge on deployment of miRNAs to increase litchi fruit resistance against fungal disease.

Genome-wide identification and characterization of bZIP transcription factors in relation to litchi (Litchi chinensis Sonn.) fruit ripening and postharvest storage.

Basic leucine zipper (bZIP) is one of the largest transcription factor families and involved in diverse biological processes in plants. However, information on the functions of bZIP transcription factors in litchi fruit at genomic level is limited. Here, 54 LcbZIPs were identified from litchi genome and divided into 14 subfamilies: A, B, C, D, E, F, G, H, I, K, L, M, O and S. Further analysis on the distribution and collinearity of these LcbZIPs on chromosomes was conducted. Meanwhile, gene structure, promoter sequence as well as possible protein subcellular localizations of these LcbZIPs were characterized. Further, gene expression analysis of LcbZIPs accompanied with cis-element analysis as well as molecular interaction network provided further information on potential biological roles of LcbZIPs in litchi fruit development, senescence and response to fungal infection. Our results suggested that some members from subfamily C and S (LcbZIP7, LcbZIP21, LcbZIP28) as well as LcbZIP1 and LcbZIP4 might be involved in the regulation of litchi fruit senescence during postharvest storage. Additionally, subfamily D of LcbZIPs, especially LcbZIP40/41, might play important roles in the litchi fruit response to pathogen infection. Altogether, this study is beneficial to understand the function and structure of LcbZIP gene in litchi fruit.

Incorporating message format into user evaluation of microblog information credibility: A nonlinear perspective.

The spreading of misinformation and disinformation is a great problem on microblogs, leading user evaluation of information credibility a critical issue. This study incorporates two message format factors related to multimedia usage on microblogs (vividness and multimedia diagnosticity) with two well-discussed factors for information credibility (i.e., argument quality and source credibility) as a holistic framework to investigate user evaluation of microblog information credibility. Further, the study draws on two-factor theory and its variant three-factor lens to explain the nonlinear effects of the above factors on microblog information credibility. An online survey was conducted to test the proposed framework by collecting data from microblog users. The research findings reveal that for the effects on microblog information credibility: (1) argument quality (a hygiene factor) exerts a decreasing incremental effect; (2) source credibility (a bivalent factor) exerts only a linear effect; and (3) multimedia diagnosticity (a motivating factor) exerts an increasing incremental effect. This study adds to current knowledge about information credibility by proposing an insightful framework to understand the key predictors of microblog information credibility and further examining the nonlinear effects of these predictors.

New insights into the evolution of host specificity of three Penicillium species and the pathogenicity of P. Italicum involving the infection of Valencia orange (Citrus sinensis).

Blue and green molds, the common phenotypes of post-harvest diseases in fruits, are mainly caused by Penicillium fungal species, including P. italicum, P. digitatum, and P. expansum. We sequenced and assembled the genome of a P. italicum strain, which contains 31,034,623 bp with 361 scaffolds and 627 contigs. The mechanisms underlying the evolution of host specificity among the analyzed Penicillium species were associated with the expansion of protein families, genome restructuring, horizontal gene transfer, and positive selection pressure. A dual-transcriptome analysis following the infection of Valencia orange (Citrus sinensis) by P. italicum resulted in the annotation of 9,307 P. italicum genes and 24,591 Valencia orange genes. The pathogenicity of P. italicum may be due to the activation of effectors, including 51 small secreted cysteine-rich proteins, 110 carbohydrate-active enzymes, and 12 G protein-coupled receptors. Additionally, 211 metabolites related to the interactions between P. italicum and Valencia orange were identified by gas chromatography-time of flight mass spectrography, three of which were further confirmed by ultra-high performance liquid chromatography triple quadrupole mass spectrometry. A metabolomics analysis indicated that P. italicum pathogenicity is associated with the sphingolipid and salicylic acid signaling pathways. Moreover, a correlation analysis between the metabolite contents and gene expression levels suggested that P. italicum induces carbohydrate metabolism in Valencia orange fruits as part of its infection strategy. This study provides useful information regarding the genomic determinants that drive the evolution of host specificity in Penicillium species and clarifies the host-plant specificity during the infection of Valencia orange by P. italicum. IMPORTANCE: P. italicum GL_Gan1, a local strain in Guangzhou, China, was sequenced. Comparison of the genome of P. italicum GL_Gan1 with other pathogenic Penicillium species, P. digitatum and P. expansum, revealed that the expansion of protein families, genome restructuring, HGT, and positive selection pressure were related to the host range expansion of the analyzed Penicillium species. Moreover, gene gains or losses might be associated with the speciation of these Penicillium species. In addition, the molecular basis of host-plant specificity during the infection of Valencia orange (Citrus sinensis) by P. italicum was also elucidated by transcriptomic and metabolomics analysis. The data presented herein may be useful for further elucidating the molecular basis of the evolution of host specificity of Penicillium species and for illustrating the host-plant specificity during the infection of Valencia orange by P. italicum.

Silencing Dicer-Like Genes Reduces Virulence and sRNA Generation in Penicillium italicum, the Cause of Citrus Blue Mold.

The Dicer protein is one of the most important components of RNAi machinery because it regulates the production of small RNAs (sRNAs) in eukaryotes. Here, Dicer1-like gene (Pit-DCL1) and Dicer2-like gene (Pit-DCL2) RNAi transformants were generated via pSilent-1 in Penicillium italicum (Pit), which is the causal agent of citrus blue mold. Neither transformant showed a change in mycelial growth or sporulation ability, but the pathogenicity of the Pit-DCL2 RNAi transformant to citrus fruits was severely impaired, compared to that of the Pit-DCL1 RNAi transformant and the wild type. We further developed a citrus wound-mediated RNAi approach with a double-stranded fragment of Pit-DCL2 generated in vitro, which achieved an efficiency in reducing Pi-Dcl2 expression and virulence that was similar to that of protoplast-mediated RNAi in P. italicum, suggesting that this approach is promising in the exogenous application of dsRNA to control pathogens on the surface of citrus fruits. In addition, sRNA sequencing revealed a total of 69.88 million potential sRNAs and 12 novel microRNA-like small RNAs (milRNAs), four of which have been predicated on target innate immunity or biotic stress-related genes in Valencia orange. These data suggest that both the Pit-DCL1 and Pit-DCL2 RNAi transformants severely disrupted the biogenesis of the potential milRNAs, which was further confirmed for some milRNAs by qRT-PCR or Northern blot analysis. These data suggest the sRNAs in P. italicum that may be involved in a molecular virulence mechanism termed cross-kingdom RNAi (ck-RNAi) by trafficking sRNA from P. italicum to citrus fruits.

Effect of Ozone Treatment on Flavonoid Accumulation of Satsuma Mandarin (Citrus unshiu Marc.) during Ambient Storage.

This study aimed to compare the flavonoid accumulation between ozone-treated and untreated Satsuma mandarin (Citrusunshiu Marc.) fruits. The fruits exposed to gaseous ozone were found to have higher antioxidant activities and content of flavonoid during the storage period by ultra-high performance liquid chromatography (UPLC). To reveal the molecular regulation of flavonoid accumulation by ozone, chalcone synthase (CHS), chalcone isomerase (CHI), ß-1,3-glucanase (GLU), chitinase (CHT), phenylalanine ammonia-lyase (PAL), and peroxidase (POD) were identified and their expression was examined by quantitative real-time polymerase chain reaction (q-PCR). These results support the promising application of ozone treatment as a safe food preservation technique for controlling postharvest disease and extending shelf-life of harvested Satsuma mandarin.

Cytosporone B as a Biological Preservative: Purification, Fungicidal Activity and Mechanism of Action against Geotrichum citri-aurantii.

To prevent citrus decay caused by Geotrichum citri-aurantii, 12 natural products were isolated from two endophytic fungi, in which cytosporone B was shown to have excellent bioactivity for control of G. citri-aurantii with median effect concentration (EC50) of 26.11 µg/mL and minimum inhibitory concentration (MIC) of 105 µg/mL, and also significantly reduced the decay of sugar orange during the in vivo trials. In addition, cytosporone B could alter the morphology of G. citri-aurantii by causing distortion of the mycelia and loss of membrane integrity. Differentially expressed genes (DEGs) between cytosporone B-treated and -untreated samples were revealed by Illumina sequencing, including 3540 unigenes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that most DEGs were related to metabolic production and cell membrane. These findings suggest cytosporone B is a promising biological preservative to control citrus decay and reveal the action mechanism of cytosporone B in relation to the destruction of the fungal cell membrane at both morphological and molecular levels.

Mechanism of Cell Wall Polysaccharides Modification in Harvested 'Shatangju' Mandarin (Citrus reticulate Blanco) Fruit Caused by Penicillium italicum.

Modification of cell wall polysaccharide in the plant plays an important role in response to fungi infection. However, the mechanism of fungi infection on cell wall modification need further clarification. In this study, the effects of Penicillium italicum inoculation on 'shatangju' mandarin disease development and the potential mechanism of cell wall polysaccharides modification caused by P. italicum were investigated. Compared to the control fruit, P. italicum infection modified the cell wall polysaccharides, indicated by water-soluble pectin (WSP), acid-soluble pectin (ASP), hemicellulose and lignin contents change. P. italicum infection enhanced the activities of polygalacturonase (PG), pectin methylesterase (PME), and the expression levels of xyloglucanendotransglucosylase/hydrolase (XTH) and expansin, which might contribute to cell wall disassembly and cellular integrity damage. Additionally, higher accumulation of reactive oxygen species (ROS) via decreasing antioxidant metabolites and the activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) also contributed to the cell wall polysaccharides modification. Meanwhile, the gene expression levels of hydroxyproline-rich glycoprotein (HRGP) and germin-like protein (GLP) were inhibited by pathogen infection. Altogether, these findings suggested that cell wall degradation/modification caused by non-enzymatic and enzymatic factors was an important strategy for P. italicum to infect 'shatangju' mandarin.

A Non-Liner Decision Model for Green Crowdfunding Project Success: Evidence from China.

Green growth and environmental sustainability have become a significant focus in today's living. We believe that green crowdfunding project can make an important contribution to the creation and evaluation of environmental systems. This study aims to investigate the determinants of green crowdfunding project success. Contrary to the linear relationship in previous literature, we propose a non-liner decision model that includes three determinants, funds pledge, goal setting, and project duration to predict project success. The quantitative approach method was employed. We crawl data on 1389 green crowdfunding projects from Tencent Lejuan, a crowdfunding platform in China. By using ordinary least square method to conduct data analysis, we find that the effect of goal setting on project success is non-linear as low and moderate levels of goal setting are not always likely to have a significant impact on project success, but the presence of a higher goal is likely to exert a positive effect on project success. Moreover, results show that the effect of project duration on project success is non-linear as short and moderate levels of duration is not always certain to have significant impact on project success, but the presence of a long duration is likely to exert a positive effect on project success. This study has implications for fund-seekers for green crowdfunding projects and managers of crowdfunding platforms.

Three-dimensional reduced graphene oxide aerogel modified electrode for the sensitive quercetin sensing and its application.

Quercetin belongs to flavonoid drug that has favorable properties such as antiviral, anticancer, anti-allergic and anti-tumor. Therefore a sensitive method is highly required for quercetin determination. In this paper, a three-dimensional reduced graphene oxide aerogel (3D-rGA) with excellent porous framework was synthesized via one-step hydrothermal technique. The characteristics and performances of 3D-rGA were checked by SEM, TEM, BET, XRD, Raman, FT-IR, XPS and electrochemical methods, which exhibited good properties including unique porous structure, large surface area and excellent conductivity. 3D-rGA was further used as the modifier on carbon ionic liquid electrode (CILE) to construct a modified electrode, which was applied to sensitive and selective determination of quercetin. Electrochemical responses of quercetin were accelerated with a pair of symmetrical cyclic voltammetric peaks in good shape appeared and the electrochemical parameters were calculated. The sensitive oxidation response of quercetin from differential pulse voltammetry was verified. Under the selected conditions, electroanalysis of quercetin was established by plotting the oxidation peak currents against quercetin concentrations with linear regression analysis. A wider linear range from 0.1 µmol/L to 100.0 µmol/L was obtained with a detection limit of 0.065 µmol/L (3S0/S). This as-explored approach could be successfully utilized for quercetin detection in Ginkgo tablets.

Complete genome sequencing of the luminescent bacterium, Vibrio qinghaiensis sp. Q67 using PacBio technology.

Vibrio qinghaiensis sp.-Q67 (Vqin-Q67) is a freshwater luminescent bacterium that continuously emits blue-green light (485 nm). The bacterium has been widely used for detecting toxic contaminants. Here, we report the complete genome sequence of Vqin-Q67, obtained using third-generation PacBio sequencing technology. Continuous long reads were attained from three PacBio sequencing runs and reads >500 bp with a quality value of >0.75 were merged together into a single dataset. This resultant highly-contiguous de novo assembly has no genome gaps, and comprises two chromosomes with substantial genetic information, including protein-coding genes, non-coding RNA, transposon and gene islands. Our dataset can be useful as a comparative genome for evolution and speciation studies, as well as for the analysis of protein-coding gene families, the pathogenicity of different Vibrio species in fish, the evolution of non-coding RNA and transposon, and the regulation of gene expression in relation to the bioluminescence of Vqin-Q67.

Synthesis and characterization of hyperbranched poly(ester-amine) by Michael addition polymerization.

A series of tertiary amine-based hyperbranched poly(amine-ester)s have been synthesized by Michael addition polymerization of trifunctional monomer, TMEA and difunctional monomer, diacylates in chloroform, and the resultant polymers were subsequently treated with mercaptoethenol or 1-dodecanethiol for improving stability in storage. The caption efficiency of mercaptoethanol is much better than that of 1-dodecanthiol. Kinetic study reveals that the thiol group is consumed faster than the acrylate group when the polymerization with feed molar ratio of diacrylate/TMEA = 2/1 was carried out. At initial polymerization, monomer conversion increases fast, but the molecular weights increase slowly and sharp increase of the molecular weight occurs at the final polymerization. The hyperbranched polymers were well characterized by 1H NMR spectra and TD-SEC, and DBs of the polymers obtained are between 0.6 and 0.82, as well as the molar ratios of diacrylate/TMEA in the hyperbranched polymers are between 1.60 and 1.82. The fluorescence efficiency and quantum yields of HypET20, HypHT24 and HypDT24 has the following sequence: HypET20 > HypHT24 > HypDT24.