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In the ethylene signalling pathway, EIN2 is an essential signal transducer linking ethylene perception on endoplasmic reticulum to transcriptional regulation in the nucleus, EIN3/EIL1 transcription...

As an inhibitor of ethylene receptors, 1-methylcyclopropene (1-MCP) can delay the ripening of papaya. However, improper 1-MCP treatment will cause a rubbery texture in papaya. Understanding of the underlying mechanism is still lacking. In the present work, a comparative sRNA analysis was conducted after different 1-MCP treatments and identified a total of 213 miRNAs, of which 44 were known miRNAs and 169 were novel miRNAs in papaya. Comprehensive functional enrichment analysis indicated that plant hormone signal pathways play an important role in fruit ripening. Through the comparative analysis of sRNAs and transcriptome sequencing, a total of 11 miRNAs and 12 target genes were associated with the ethylene and auxin signaling pathways. A total of 1741 target genes of miRNAs were identified by degradome sequencing, and nine miRNAs and eight miRNAs were differentially expressed under the ethylene and auxin signaling pathways, respectively. The network regulation diagram of miRNAs and target genes during fruit ripening was drawn. The expression of 11 miRNAs and 12 target genes was verified by RT-qPCR. The target gene verification showed that cpa-miR390a and cpa-miR396 target CpARF19-like and CpERF RAP2-12-like, respectively, affecting the ethylene and auxin signaling pathways and, therefore, papaya ripening.

Brassinosteroids act by delaying fruit ripening. The effects of different concentrations of 2,4-epibrassinolide (eBL) treatments on carambola fruit ripening were investigated. The results show that treatment of 2.8 mg L–1, eBL with 10 min effectively delays ripening and maintains the quality of carambola fruit. This is achieved by retarding color changes and firmness losses while maintaining high level of soluble protein content and vitamin C, and low organic acid content. eBL-delayed senescence may be due to the inhibition of respiration rate and enhanced antioxidant system. It is noteworthy that eBL treatment markedly reduces the content of fructose-6-phosphate (6-P-F) and enhances the activity of cytochrome oxidase (CCO), and the total activity of glucose-6-phosphate dehydrogenase (G-6-PDH) and 6-phosphate gluconate dehydrogenase (6-PGDH). eBL treatment induces the IAA and GA contents but reduces that of ABA. In general, senescence retardation and quality improvement by eBL treatment may be due to the enhanced antioxidant capacity and altered respiratory pathways.

Bromodomain-containing proteins are known readers of histone acetylation that regulate chromatin structure and transcription. Although the functions of bromodomain-containing proteins in development, homeostasis, and disease states have been well studied, their role in self-renewal of hematopoietic stem and progenitor cells (HSPCs) remains poorly understood. Here, we performed a chemical screen using nine bromodomain inhibitors and found that the bromodomain and PHD finger-containing protein 1 (Brpf1) inhibitor OF-1 enhanced the expansion of Lin−Sca-1+c-Kit+ HSPCs ex vivo without skewing their lineage differentiation potential. Importantly, our results also revealed distinct functions of Brpf1 isoforms in HSPCs. Brpf1b promoted the expansion of HSPCs. By contrast, Brpf1a is the most abundant isoform in adult HSPCs but enhanced HSPC quiescence and decreased the HSPC expansion. Furthermore, inhibition of Brpf1a by OF-1 promoted histone acetylation and chromatin accessibility leading to increased expression of self-renewal-related genes (e.g. Mn1). The phenotypes produced by OF-1 treatment can be rescued by suppression of Mn1 in HSPCs. Our findings demonstrate that this novel bromodomain inhibitor OF-1 can promote the clinical application of HSPCs in transplantation.

Calcium ions (Ca2+) is an important element for plant cells and serve as second messengers, playing an important role in the regulation of plant physiology, specifically in postharvest fruits and vegetables. The roles of calcium and calcium-sensing receptors have been exhaustively studied in plants, and some of these receptors have been found to play a role in fruit ripening as well. However, a comprehensive overview of the manner in which calcium participates in regulating fruit development, ripening and the molecular mechanisms underlying fruit physiology and ripening have not been conducted. In this study, we reviewed the comprehensive roles of calcium in fruit development and ripening, attempting to elucidate the possible physiological and molecular mechanisms in fruit ripening. The roles of calcium sensors, including calmodulin (CaM), calmodulin-like (CML) proteins, calcineurin B-like proteins (CBL), and calcium-dependent protein kinases (CDPK), are discussed in fruit development and ripening. The interaction between the calcium signal and phytohormone signal pathways in fruit development and fruit ripening was also reviewed. The integral associations among calcium, calcium sensors, and fruit ripening were highlighted. This study provides a comprehensive overview of calcium signals in fruit development and ripening and may contribute to possible areas of interest for future research.

Banana fruit is sensitive to chilling injury, which not only causes physical damage but also dramatically reduces fruit flavor. In this work, we evaluated the influence of non-chilling low temperature (NCT, 13 °C) and chilling temperature (CT, 5 °C) storage on volatiles production in banana in comparison to control conditions (20 °C) and evaluated the possible mechanisms. We found that CT storage caused chilling injury, which negatively affected the physical appearance of the fruit and dramatically reduced volatiles production, especially fruity note volatiles, such as esters. In contrast, NCT storage only reduced the production of a few specific volatiles. Both NCT and CT affected volatile-related amino acid and biosynthetic precursors of fatty acid compositions. The expression levels of the volatiles biosynthesis-related genes, MaHPL, MaLOX, and MaAAT, were repressed by low temperature (NCT and CT), particularly chilling temperature, while MaADH and MaPDC were up-regulated. These results suggest that CT significantly reduces volatiles production by regulating different key enzymes and genes involved in volatiles biosynthetic pathways and is mainly mediated via the repression of the lipoxygenase and amino acid metabolic pathways.

Inflammatory bowel disease (IBD)-related inflammation is closely associated with the initiation and progression of colorectal cancer. IBD is generally treated with 5-aminosalicylic acid and immune-modulating medication, but side effects and limitations of these therapies are emerging. Thus, the development of novel preventative or therapeutic approaches is imperative. Here, we constructed a dextran sodium sulphate (DSS)-induced IBD mouse model that was infected with monosexual Schistosoma japonicum cercariae (mSjci) at day 1 or administered dexamethasone (DXM) from days 3 to 5 as a positive control. The protective effect of mSjci on IBD mice was evaluated through their assessments of their clinical signs, histopathological lesions and intestinal permeability. To uncover the underlying mechanism, the Th1/Th2 balance and Treg cell population were also examined. Additionally, the alterations in the gut microbiota were assessed to investigate the interaction between the mSjci-modulated immune response and pathogenic microbiome. Mice treated with DSS and mSjci showed fewer IBD clinical signs and less impaired intestinal permeability than DSS-treated mice. Mechanistically, mSjci modulated the Th1/Th2 balance by repressing IFN-γ production, promoting IL-10 expression and enhancing the Treg subset population. Moreover, mSjci notably reshaped the structure, diversity and richness of the gut microbiota community and subsequently exerted immune-modulating effects. Our findings provide evidence showing that mSjci might serve as a novel and effective protective strategy and that the gut microbiota might be a new therapeutic target in IBD.

Studies have confirmed the relationship between dysregulated long noncoding RNAs and melanoma pathogenesis. However, the regulatory functions of long intergenic non-protein coding RNA 1291 (LINC01291) in melanoma remain unknown. Therefore, we evaluated LINC01291 expression in melanoma and explored its roles in regulating tumor behaviors. Further, the molecular events via which LINC01291 affects melanoma cells were investigated. LINC01291 expression in melanoma cells was analyzed using The Cancer Genome Atlas database and quantitative real-time polymerase chain reaction. Functional assays, including the Cell Counting Kit-8 assay, colony formation assay, flow cytometry, cell migration and invasion assays, and tumor xenograft models, were used to examine LINC01291’s role in melanoma cells. Additionally, bioinformatics analysis, RNA immunoprecipitation, luciferase reporter assay, and western blotting were conducted to determine the tumor-promoting mechanism of LINC01291. LINC01291 was upregulated in melanoma tissues and cell lines. Following LINC01291 knockdown, cell proliferation, colony formation, migration, and invasion were diminished, whereas apoptosis was enhanced and the cell cycle was arrested at G0/G1. In addition, loss of LINC01291 decreased the chemoresistance of melanoma cells to cisplatin. Furthermore, LINC01291 interference inhibited melanoma tumor growth in vivo. Mechanistically, LINC01291 functions as a competing endogenous RNA by sponging microRNA-625-5p (miR-625-5p) in melanoma cells and maintaining insulin-like growth factor 1 receptor (IGF-1R) expression. Rescue experiments revealed that the roles induced by LINC01291 depletion in melanoma cells could be reversed by suppressing miR-625-5p or overexpressing IGF-1R. Our study identified the LINC01291/miR-625-5p/IGF-1R competing endogenous RNA pathway in melanoma cells, which may represent a novel diagnostic biomarker and an effective therapeutic target for melanoma.

Calcium (Ca2+) is an important second messenger involved in diverse developmental and adaptive processes in plants. Calmodulin (CaM) and calmodulin-like (CML) proteins are primary Ca2+ sensors that control diverse cellular functions. In this study, 41 genes encoding CaM and CML proteins were identified in the papaya genome, three of which were CaM and others were CML. Sequence alignment, gene structural and phylogenetic analyses revealed that all CaM/CMLs contained the EF-hand, but not other functional domains, and CaM proteins were quite conservative while CML proteins exhibited sequence diversity and structural multiformity. Promoter analysis identified different types of cis-elements related to plant growth and development, hormone response, light response, stress response and transcriptional enhancement in promoter regions of CpCaM/CML genes. Gene expression analysis showed distinctive expression profiles of the CaM/CMLs in different tissue types, different fruit developmental stages and different fruit storage conditions. Several groups of CaM/CML genes were positively or negatively regulated by high and low temperature stresses, such as CML16, CML17.1, CML24 and CML36, indicating that they may play a role in temperature stress adaption. Notably, some CaM/CML genes were rigorously regulated by ethylene (ethephon and 1-MCP treatment), either in a positive or a negative manner, such as CaM7, CML15, CML16, CML17.1, CML37 and CML46. All these results indicated that CaM and CML gene families might play important roles in fruit development, in response to temperature stresses and in fruit ripening process.

Pineapple (Ananas comosus (L.) Merr.) fruit ripen and soften rapidly after harvest. This study focused on examining the effect of wax application on the ripening and storage quality of the fruit. An optimized waxing treatment (65 g L−1 for 1 min) could effectively control fruit ripening by delaying fruit color change, decreasing the respiration rate and ethylene production, decreasing content of organic acids and relieving the symptoms of internal browning of pineapple fruit. Waxing enhanced the relative level of pentose phosphate pathway of respiration and affected the enzymes involved in organic acid metabolism. Waxing also reinforced the antioxidant system and enhanced the expression levels of genes related to defense, such as PGIP. These results indicated that wax treatment could effectively improve the fruit quality, mainly through the reduction of organic acid content.

Tumor necrosis factor (TNF)-alpha-induced protein 8-like 2 (TNFAIP8L2; also termed TIPE2) has been shown to be involved in both the immune-negative modulation and cancer. We previously found that TIPE2 is lost in human gastric cancer, and TIPE2 restoration suppresses gastric cancer growth by induction of apoptosis and impairment of protein kinase B (PKB/AKT) and extracellular signal-regulated kinase-1/2 (ERK1/2) signaling. However, its correlation with epithelial-mesenchymal transition (EMT) in gastric cancer is largely elusive. In the present report, we carried out a gain-of-function study in AGS and HGC-27 human gastric cancer cells by adenovirus-mediated human TIPE2 gene transfer (AdVTIPE2). We then examined the effects of AdVTIPE2 on in vitro migration and invasion of AGS and HGC-27 tumor cells by wound-healing assay and Transwell invasion assay, respectively. We also investigated the effects of AdVTIPE2 on in vivo lung metastasis of AGS and HGC-27 tumor cells by intravenous (i.v.) injection in athymic BALB/c nude mice. We demonstrated that AdVTIPE2 remarkably suppressed the migratory, invasive and metastatic potential of AGS and HGC-27 tumor cells in vitro and in vivo in BALB/c nude mouse model. Mechanistically, AdVTIPE2 obviously upregulated E-cadherin epithelial marker in AGS and HGC-27 tumor cells, whereas it downregulated N-cadherin and Vimentin mesenchymal markers, Snail1, Snail2/Slug and Zeb1 EMT-inducing transcription factors (EMT-TFs), and tripartite motif-containing 29 (TRIM29) and phosphatase regenerating liver 3 (PRL-3) gastric cancer-specific metastasis markers. Importantly, glycogen synthase kinase-3β (GSK-3β) inhibitor VIII and 26S proteasome inhibitor MG132 assays revealed that TIPE2 downregulated Snail1 and Snail2/Slug in a GSK-3β- and proteasome-dependent manner possibly by impairing AKT signaling. Our data provided the first evidence that TIPE2 inhibits gastric cancer cell migration, invasion and metastasis very probably via reversal of EMT, revealing that TIPE2 may be a novel therapeutic target for human gastric cancer EMT and metastasis.

Wine frying status is one of the most important processes in the brewing of Chinese yellow rice wine (CYW) and has a great influence on the quality and flavor of CYW. The present work determined the ethyl carbamate (EC) concentration by gas chromatography-mass spectrometry (GC-MS) and aroma compounds by headspace solid-phase microextraction GC-MS (HS-SPME-GC-MS) during wine frying status in CYW. In addition, effects of wine frying conditions on the changes of EC and aroma compounds were also investigated. Results indicated that EC concentration increased along with the increase of wine frying temperature and time. Pearson test indicated that EC had highly significant correlation (p

In the present work, fruit quality and antioxidant property of twenty-two cultivars of mulberry (Morus sp.) from China were evaluated. The results showed that contents of total soluble solid (TSS), titratable acid (TA), phenolics and anthocyanin as well as antioxidant enzyme activity and antioxidant capacity varied with cultivars. Among the twenty-two cultivars, contents of TSS and TA ranged from 6.2 to 16.00% and 0.20 to 2.05% citric acid, with Jiguihua and Mengjian 5 showing the highest level, respectively. Most of cultivars were rich in anthocyanin and phenolics, and the highest contents were detected in Zhongshen 831. Highest activities of antioxidant enzymes, including As-POD, G-POD, CAT, GR, GSH-POD and SOD were found in Taiwanguosang, Zhenzhubai, Mengjian 4, 72C002, Da 10, and Jiguihua, respectively. Moreover, principal component analysis revealed that Zhongshen 831, Huayang novel and Zhongsang 5801 exhibited higher antioxidant capacities.

Tissue-resident memory T cells (TRMs) have a key role in mediating the host defense against tuberculosis (TB) in mice, but their human counterparts have not been well characterized. In this article, we recruited patients with TB and determined TRM frequency, trafficking, activation marker expression, and cytokine production by flow or mass cytometry at different infection sites, including peripheral blood, pleural fluid, bronchoalveolar lavage fluid, and lung. We found a high frequency of TRMs at all infection sites apart from the peripheral blood. These TRMs exhibited a memory phenotype, were highly activated (based on CD38 and HLA-DR expression), and expressed high levels of trafficking (CCR5 and CXCR6) and exhaustion (PD-1) markers. When stimulated with Mycobacterium tuberculosis, TRMs secreted cytokines, including IFN-γ, TNF-α, and IL-2, and exhibited a multifunctional phenotype. TRMs limited intracellular M. tuberculosis replication in macrophages. These data inform our current understanding of immunosurveillance at different infection sites in patients with TB.

Background: Tuberculosis (TB) continues to be a critical global health problem, which killed millions of lives each year. Certain circulating cell subsets are thought to differentially modulate the host immune response towards Mycobacterium tuberculosis (Mtb) infection, but the nature and function of these subsets is unclear. Methods: Peripheral blood mononuclear cells (PBMC) were isolated from healthy controls (HC), latent tuberculosis infection (LTBI) and active tuberculosis (TB) and then subjected to single-cell RNA sequencing (scRNA-seq) using 10 × Genomics platform. Unsupervised clustering of the cells based on the gene expression profiles using the Seurat package and passed to tSNE for clustering visualization. Flow cytometry was used to validate the subsets identified by scRNA-Seq. Findings: Cluster analysis based on differential gene expression revealed both known and novel markers for all main PBMC cell types and delineated 29 cell subsets. By comparing the scRNA-seq datasets from HC, LTBI and TB, we found that infection changes the frequency of immune-cell subsets in TB. Specifically, we observed gradual depletion of a natural killer (NK) cell subset (CD3-CD7+GZMB+) from HC, to LTBI and TB. We further verified that the depletion of CD3-CD7+GZMB+ subset in TB and found an increase in this subset frequency after anti-TB treatment. Finally, we confirmed that changes in this subset frequency can distinguish patients with TB from LTBI and HC. Interpretation: We propose that the frequency of CD3-CD7+GZMB+ in peripheral blood could be used as a novel biomarker for distinguishing TB from LTBI and HC. Fund: The study was supported by Natural Science Foundation of China (81770013, 81525016, 81772145, 81871255 and 91942315), National Science and Technology Major Project (2017ZX10201301), Science and Technology Project of Shenzhen (JCYJ20170412101048337) and Guangdong Provincial Key Laboratory of Regional Immunity and Diseases (2019B030301009). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Keyword: Tuberculosis, Single-cell RNA sequencing, CD3-CD7+GZMB+, NK cells

Low-temperature storage is a common strategy for preserving and transporting vegetables and fruits. However, many fruits are hypersensitive to chilling injury, including bananas. In the present study, storage conditions of 11 &deg, C delayed the ripening of Fenjiao (Musa ABB Pisang Awak) banana, and the pulp could be softened after ethephon treatment. Storage conditions of 7 &deg, C prevented fruit from fully softening, and fruit contained a significantly higher starch content and lower soluble sugar content. MaEBF1, a critical gene component in the ethylene signaling pathway, was repressed during ripening after fruit had been stored for 12 days at 7 &deg, C. The expression of a series of starch degradation-related genes and a MaNAC67-like gene were also severely repressed. Both MaEBF1 and MaNAC67-like genes were ethylene-inducible and localized in the nucleus. MaNAC67-like protein was able to physically bind to the promoter of genes associated with starch degradation, including MaBAM6, MaSEX4, and MaMEX1. Yeast two-hybrid, GST-pull down, and BiFC assays showed that MaEBF1 interacted with the MaNAC67-like protein, and their interaction further activated the promoters of MaBAM6 and MaSEX4. The current study indicates that MaNAC67-like is a direct regulator of starch degradation and potential for involvement in regulating chilling-inhibited starch degradation by interacting with the ethylene signaling components in banana fruit. The present work paves the way for further functional analysis of MaEBF1 and MaNAC67-like in banana, which will be useful for understanding the regulation of banana starch metabolism and fruit ripening.

Background Ethylene promotes fruit ripening whereas 1-methylcyclopropene (1-MCP), a non-toxic antagonist of ethylene, delays fruit ripening via the inhibition of ethylene receptor. However, unsuitable 1-MCP treatment can cause fruit ripening disorders. Results In this study, we show that short-term 1-MCP treatment (400 nL•L− 1, 2 h) significantly delays papaya fruit ripening with normal ripening characteristics. However, long-term 1-MCP treatment (400 nL•L− 1, 16 h) causes a “rubbery” texture of fruit. The comparative transcriptome analysis showed that a total of 5529 genes were differently expressed during fruit ripening compared to freshly harvested fruits. Comprehensive functional enrichment analysis showed that the metabolic pathways of carbon metabolism, plant hormone signal transduction, biosynthesis of amino acids, and starch and sucrose metabolism are involved in fruit ripening. 1-MCP treatment significantly affected fruit transcript levels. A total of 3595 and 5998 differently expressed genes (DEGs) were identified between short-term 1-MCP, long-term 1-MCP treatment and the control, respectively. DEGs are mostly enriched in the similar pathway involved in fruit ripening. A large number of DEGs were also identified between long-term and short-term 1-MCP treatment, with most of the DEGs being enriched in carbon metabolism, starch and sucrose metabolism, plant hormone signal transduction, and biosynthesis of amino acids. The 1-MCP treatments accelerated the lignin accumulation and delayed cellulose degradation during fruit ripening. Considering the rubbery phenotype, we inferred that the cell wall metabolism and hormone signal pathways are closely related to papaya fruit ripening disorder. The RNA-Seq output was confirmed using RT-qPCR by 28 selected genes that were involved in cell wall metabolism and hormone signal pathways. Conclusions These results showed that long-term 1-MCP treatment severely inhibited ethylene signaling and the cell wall metabolism pathways, which may result in the failure of cell wall degradation and fruit softening. Our results reveal multiple ripening-associated events during papaya fruit ripening and provide a foundation for understanding the molecular mechanisms underlying 1-MCP treatment on fruit ripening and the regulatory networks. Electronic supplementary material The online version of this article (10.1186/s12870-019-1904-x) contains supplementary material, which is available to authorized users.

Ethylene plays a pivotal role in climacteric fruit ripening; whereas 1-MCP, a non-toxic antagonist of ethylene, prevents ethylene-dependent responses and fruit ripening. In this study, a short-term treatment (1 h) with 400 nL L−1 1-MCP delayed the ripening of harvested papaya. However, long-term application of 1-MCP (400 nL L−1, 16 h) resulted in abnormal fruit ripening, with the fruits exhibiting normal yellowing without softening, significantly higher cellulose and lignin contents, and intact cell walls (CW). Furthermore, we found that long-term treatment with 1-MCP significantly inhibited the expression of CpEBF1, an EIN3-binding F-box-1 gene. A protein interaction analysis using yeast two-hybrid, BiFC and GST pull-down assays showed that CpEBF1 interacts with the CpMADS1/3 and CpEIL1 proteins. The interaction of CpEBF1 with CpMADS1/3 further activated the activities of CW-degradation gene promoters. Subcellular localization showed that these proteins were localized in the nucleus. Additionally, the expression levels of CpMADS1/3, CpEIL1, and several CW-degradation-related genes were significantly downregulated by long-term 1-MCP treatment. Therefore, we propose that the inhibited expression of CpEBF1 and CpMADS1/3 resulted in the repressed activation of CW-degradation-related genes via their interaction, thereby resulting in fruit softening disorders., Papaya: Anti-ripening treatment prevents degradation of cell wall Long-term treatment with an anti-ripening agent inhibits the expression of regulatory genes that normally break down the cell wall of the papaya fruit. A team from Guangzhou’s South China Agricultural University led by Xueping Li and Weixin Chen applied a hormone inhibitor to papayas at the breaker stage of fruit ripening. 1 h of treatment delayed ripening, whereas 16 h of treatment caused the fruit to become rubbery, with significantly higher levels of cellulose and lignin, both structural components of the cell wall. The researchers identified two genes with reduced expression following extended hormone-blocking treatment. Both normally encode proteins that aid in degrading the cell wall to promote fruit ripening. The findings thus offer a molecular explanation for why misuse of anti-ripening agents on papaya fruits can lead to undesirable characteristics.

Benzothiadiazole (BTH) works as a plant activator. The effects of different BTH treatments and fungicides SPORGON on fruit ripening and disease incidence were investigated. The results showed that BTH treatment significantly delayed fruit ripening, maintained fruit firmness, color, and good fruit quality, and dramatically reduced the incidence of disease. BTH effectively inhibited the invasion and development of pathogenic bacteria and controlled the occurrence of disease. BTH treatment enhanced the activities of defense-related enzymes, including chitinase, phenylalanine ammonia-lyase, peroxidase, and polyphenol oxidase, increased the content of hydrogen peroxide and total antioxidant capacity, and reduced malondialdehyde content. Cellular structure analysis after inoculation confirmed that BTH treatment effectively maintained the cell structural integrity. SPORGON did not provide benefits for delaying fruit ripening or for the resistance system, while it can control the disease only during the earlier stage and not at later stages.

1-Methylcyclopropene (1-MCP) has been widely used to manipulate fruit ripening. However, inappropriate treatment with 1-MCP may cause ripening disorders. In this study, we observed that the appropriate concentration of 1-MCP (400 nl L−1, 6 h) (1-MCP400) significantly delayed the ripening of Fenjiao banana. However, a high concentration of 1-MCP (3200 nl L−1, 6 h) (1-MCP3200) resulted in abnormal Fenjiao banana that ripened with softened fruit that had a green peel. An RNA sequencing analysis showed that a large number of differentially expressed genes (DEGs) in the fruit peel and pulp were screened out from fruit that were ripened as controls. A KEGG analysis revealed that the metabolic pathways of plant hormone signal transduction, starch and sucrose metabolism, phenylpropanoid biosynthesis, photosynthesis and biosynthesis of amino acids were significantly enriched during fruit ripening. The fruit transcript level of fruit was markedly altered by 1-MCP treatment. Large numbers of DEGs were also detected between high and appropriate concentrations of 1-MCP in the peel and pulp. A comprehensive functional enrichment analysis showed that most of the DEGs involved in photosynthesis, cysteine and methionine metabolism, phenylpropanoid biosynthesis, amino sugar and nucleotide sugar metabolism, plant hormone signal transduction, starch and sucrose metabolism were enriched. RT-qPCR verified the RNA-Seq results, which indicated that 1-MCP3200 severely repressed the expression of genes involved in ethylene (MaACS1, MaACO1, MaETR2-like, MaERF003, MaERF012 and MaERF113), auxin (MaARF19-like, MaSAUR71-like and MaSAUR72-like) and abscisic acid (MaPYL3-like and MaABI5-like) signaling pathways, chlorophyll and cell wall degradation, and starch and sucrose metabolism but induced the expression of genes in lignin synthesis. These genes were consistently expressed in the pulp and peel following control and 1-MCP400 treatment, but their expression was inconsistent following 1-MCP3200 treatment, which may result in the failure of the peel to turn yellow in the 1-MCP3200 group.

Fenjiao (Musa ABB Pisang Awak) is a popular banana cultivar due to its good taste and stress resistance, but it has a short shelf-life and deteriorates rapidly post-harvest. The effects of 1-methylcyclopropene (1-MCP) treatment on fruit physiology and quality and transcriptomic profiles are investigated in this study. The results showed that 1-MCP significantly delayed fruit ripening by repressing fruit softening and inhibiting the respiratory rate and ethylene production. The 1-MCP treatment delayed sugar accumulation and influenced the content of the precursors of the biosynthesis of aroma volatiles. 1-MCP reduced the production of flavor-contributing volatile esters isoamyl isobutyrate, isoamyl acetate and trans-2-hexenal and hexanal, but dramatically increased the hexyl acetate production at the full-ripening stage. The transcriptomic analysis showed that 1-MCP dramatically affected the transcript profiles during fruit ripening, especially the KEGG pathways involved in amino acid metabolism, biosynthesis of other secondary metabolites, carbohydrate metabolism, lipid metabolism, signal transduction, and translation classes. The key genes and the corresponding enzyme activities involved in the volatile and ethylene synthesis were severely repressed due to the 1-MCP treatment. The 1-MCP treatment effectively delayed Fenjiao fruit ripening, but affected volatile production by reducing the precursor production and expression level of genes involved in the metabolism pathways of ethylene, auxin and volatiles.

Background H3K27me3 modification inactivates gene transcription by resulting in condensed chromatin. However, the landscape and biological functions of H3K27me3 in breast cancer remain unclear. Methods Fluorescence enzyme assay was used to analyze the cell proliferation. Transwell assay was used to test the ability of migration and invasion in MDA-MB-231 cells with designed treatment. Transfection of exogenous plasmid was used to intervene specific gene expression. Nude mouse tumor xenograft model was employed to detect the effect of GSKJ-4 in vivo. ChIP-Seq analyzed the modification state of H3K27me3 around the TSS of the gene CEMIP. RNA-Seq was used to analyze the mRNA levels after treating with GSKJ-4 in MDA-MB-231 cells. Results Loss of H3K27me3 is specific for aggressive subtypes of breast cancer and may be a useful diagnostic marker. Epigenetic chemical screening identified histone H3K27me3 demethylation inhibition as a therapeutic strategy for triple-negative breast cancer (TNBC). Functional studies and RNA-seq/ChIP-seq data revealed that inactivation of the protein CEMIP (which is translated by oncogene KIAA1199) by increasing H3K27me3 leads to decreased tumor cell growth and migration. Moreover, survival analysis showed that CEMIP was associated with poor outcome in TNBC. Conclusions Our data suggest H3K27me3 loss as an important event in CEMIP mediated breast cancer carcinogenesis and progression. Loss of H3K27me3 is specific for aggressive subtypes of breast cancer and may be a useful diagnostic marker.

Backgroud: Beijing was hyper-endemic for hepatitis A until the 1990s and has been vaccinating against hepatitis A since 1994. The objective is to study the epidemiology and changes of antibody level of hepatitis A from 1990 to 2017. Methods: A multistage randomized cluster sampling serological cross-sectional study was conducted in individuals over one year old in 1992, 2006 and 2014 in Beijing. Venous blood samples were collected to test anti-HAV antibody. The incidence data of hepatitis A were obtained from National Notifiable Disease Reporting System (NNDRS) and CDC statistics in Beijing. The vaccination data of hepatitis A immunization were acquired from Beijing Immune Information System. Results: From 1990 to 2017, the reported incidence rate of HAV in Beijing declined from 59.41/100,000 in 1990 to 0.80/100,000 in 2017. The average age of HAV infection was postponed from individuals under 20 years old to individuals over 20 years old. After hepatitis A vaccine was introduced to Beijing, the outbreak of hepatitis A decreased sharply. Adjusted anti-HAV positive rate in general population was 68.23%, 81.73% and 82.47% respectively in 1992, 2006 and 2014. Due to hepatitis A vaccination conducted in children, the anti-HAV positive rate in individuals under 20 years old increased from 1992 to 2014, while in individuals over 20, this rate was barely changed. The coverage rate in target population was higher than 99% after hepatitis A vaccine was integrated into Expanded Program on Immunization (EPI). Conclusion: Incidence rate of hepatitis A in Beijing has decreased dramatically from 1990 to 2017. Hepatitis A vaccine plays an important role in protecting individuals under 20 years old. A higher proportion of adults will be susceptible to hepatitis A virus due to the decay of antibodies as they grow up from childhood to adulthood, which may result in possible outbreak of hepatitis A.

This study aimed to evaluate the potential impacts of an introduced clam Mercenaria mercenaria on estuarine ecosystem, and implications for the niche competition with a native clam Meretrix meretrix. The biodeposition, respiration, and excretion rates of M. mercenaria were determined seasonally using a sediment trap and a closed respirator in field. The biodeposition rates of M. mercenaria were 0.06–0.37 g/ (ind.·d), and the respiration rates were 0.31–14.66 mg/(ind.·d). The ammonia and phosphate excretion rates were 0.18–36.70 and 1.44–14.87 μg/(ind.·d), respectively. The hard clam M. mercenaria may discharge dry deposits up to 2.1×105 t, contribute 18.3 t ammonia and 9.0 t phosphate to culture ponds, and consume 7.9×103 t O2 from ponds annually. It suggested that the hard clam M. mercenaria might play an important role in pelagic-benthic coupling in pond ecosystem through biodeposition and excretion. A comparison of the key physiological parameters of the introduced clam M. mercenaria and the native clam Meretrix meretrix suggested that M. mercenaria had a niche similar to that of Meretrix meretrix in Shuangtaizi estuary and might have a potential competition with Meretrix meretrix for habitat and food if M. mercenaria species escaped from the culture pond or artificially released in estuarine ecosystem.

Banana fruits harvested at the mature green stage were treated with 60 μL L −1 nitric oxide (NO) for 3 h at 22 °C, and then stored at 7 ± 1 °C with 90% RH for 15 days. The results showed that the application of NO at 60 μL L −1 was most effective in reducing chilling injury in banana fruit. The treatment reduced increases in electrolyte leakage and malondialdehyde content, and delayed increases in both superoxide anion (O 2 − ) production rate and H 2 O 2 content. Fruit treated with NO exhibited higher activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX), and significantly higher expression of MaSOD , MaCAT , MaPOD and MaAPX genes than control fruit during storage. These results indicate that NO treatment might enhance chilling tolerance of banana fruit via improving the activities of antioxidant enzymes and inducing the expression of antioxidant-related genes.

Templated from the bristles on Papilio maacki wings, single porous SnO2 microtubes (SPSMs) have been synthesized by soaking and sintering. The delicate microstructure and morphology of SPSMs were characterized by SEM and TEM. Silver electrodes were precisely contacted on the two ends of an SPSM for gas-sensing measurement in reducing gases. The SPSMs were highly sensitive to trace ammonia, formaldehyde, and ethanol at room temperature. They also exhibited low working temperature and short response/recovery times. The average response and recovery times were only about 3 s and 30 s. Compared with the non-porous structure and the filled structure, the SPSMs showed higher sensitivity. The fascinating biomorphic structure of the SPSMs will open a new way for the design and application of sensor devices for the detection of harmful and toxic gases.

Objective It has been found that ulinastatin (UTI) can attenuate hepatic injury in a rat model of ischemia reperfusion (IR), but the specific mechanism is unclear. This study aims to investigate possible pathomechanism of ulinastatin in reducing the inflammatory response after hepatic IR. Methods A male sprague-dawley(SD) rat model of hepatic ischemia reperfusion injury was used. The rats were randomly divided into 4 groups on average, which were 0.9% saline and IR group as control, ulinastatin preconditioning (UPC) group, UPC+rHMGB1 (recombinant HMGB1) group and UPC +anti-HMGB1 group. Serum aminotransferases, TNF-α, IL-1 and Myeloperoxidase (MPO) levels were measured. Histopathology examination and apoptotic cell detection and the different expression of HMGB1 protein were also assessed. Results Serum levels of aminotransferases, cytokines and hepatic MPO in UPC and UPC+anti-HMGB1 groups were significantly lower than those in control group (p

Harvested papaya fruit are perishable due to rapid ripening and softening and susceptibility to biotic or abiotic stresses. Hot water treatment (HWT) can preserve fruit quality by reducing decay. The present study investigated effects of HWT on controlling fungal pathogens of papaya fruit and the possible mechanism by which HWT induced disease resistance. HWT (54 °C, 4 min) of papaya fruit had a pronounced effect on reducing the carrier rate of Colletotrichum gloeosporioides ( C. gloeosporioides ) in fruit peel, significantly inhibited the incidence of anthracnose and stem-end rot, effectively delayed fruit softening, but slightly promoted the rate of fruit coloring. HWT reduced the anthracnose index and fruit ripeness to a certain extent and induced changes in the wax arrangement on the surface of treated fruit, causing the wax to melt. The cracks and most stomata appeared to be partially or completely plugged by the melted wax, thereby providing a mechanical barrier against wound pathogens. HWT induced the expression of CpPGIP and promptly induced the expression of CpNPR1 , and then regulated the expression of the CpPR1 gene, which may enhance the resistance of the fruit to anthracnose disease and reduce the decay rate. Together, these results confirm that HWT could reduce disease incidence and induce resistance, and thus maintain postharvest quality during storage and prolong the shelf-life of papaya fruit.

Fruit softening is an ethylene-dependent ripening event. 1-Methylcyclopropene (1-MCP), a synthetic plant growth regulator structurally related to the natural plant hormone ethylene, is used to slow down the fruit ripening. However, inappropriate 1-MCP treatment tends to cause the elastic texture in papaya fruit. Constitutive triple response 1 (CTR1), a downstream protein of the ethylene receptors, acts as a negative regulator of ethylene signaling. To elucidate the signal transduction pathway involved in the ethylene regulation during papaya ripening and softening, four genes homologous to Arabidopsis CTR1 were isolated from papaya fruit and designated as CpCTR1–4. Their molecular and biochemical properties were characterized, and their expression patterns in papaya fruit after treatments with 1-MCP were investigated. Four CTR1-like genes differ in sequence length and molecular size, and have a relative distance relationship in the evolutionary tree analysis. However, sequences analysis showed that the C-terminus of CpCTR1–4 proteins contained the highly conserved kinase domains, including a protein kinase ATP-binding signature (IGAGSFGTVH) and a serine/threonine protein kinase active site signature (IVHRDLKSPNLLV). Their N-terminus contains the conserved motifs (CN box) that exist in all CTR1-like proteins. CpCTR1–4 proteins were predicted to be located differently in either chloroplast or nuclei or both. Gene expression analysis showed that 1-MCP treatment significantly repressed the expression of CpCTRs and high concentration of 1-MCP treatment had a more significant effect. These results suggested that CpCTR1–4 genes may play different roles in papaya fruit ripening and softening and that the rubbery fruit might be relate to the expression of CpCTRs genes.

Papaya fruits ( Carica papaya L. cv ‘Sui you 2’) harvested with

Δ1-Pyrroline-5-carboxylate synthetase (P5CS) catalyzes the rate-limiting step in proline biosynthesis in plants. In the present study, a full-length cDNA, denominated as CpP5CS2 for Δ1-pyrroline-5-carboxylate synthetase (P5CS), was cloned from papaya using in silico cloning and 3′- or 5′-rapid amplification of cDNA ends (RACE). The full-length cDNA of CpP5CS2 was 2583 bp, with a 2151 bp open reading frame (ORF) encoding a 717 amino acid polypeptide. Sequence analysis showed that CpP5CS2 contained several substrate-binding and catalytic domains and had high homology to other plant P5CSs. The expression pattern of CpP5CS2 in papaya under low (7 °C) and high temperature (35 °C) stresses was examined using real-time quantitative PCR. The results showed that both stresses induced CpP5CS2 expression during the storage period, and the increased expression of CpP5CS2 preceded proline accumulation. In addition, the high temperature caused a more significant induction of CpP5CS2 expression and a higher level of accumulated proline than low temperature.

The present study was performed to investigate the effect of nitric oxide (NO) fumigation on fruit ripening of harvested “Sui you 2” Carica papayas in relation to postharvest quality and soluble sugar content. Fruits were fumigated for 3 h with 60 μL/L NO and stored at 20C and 75% relative humidity for 20 days. NO treatment effectively suppressed ethylene formation and respiratory rate (CO2 levels), reduced weight loss, maintained firmness and delayed changes in peel color and soluble solid contents during 20 days of storage. The level of vitamin C initially increased and then declined slightly during storage at a slower rate in the NO-treated fruits than in controls. Exposure to 60 μL/L NO resulted in significant decreases in fructose and sucrose content. Glucose content in NO-treated fruits was higher than that in controls. Our results indicate that NO gas can be used to prolong fruit storage life and delay changes in soluble sugar content in papaya fruit. Practical Applications Nitric oxide (NO) gas, a highly reactive free radical, is being studied to resist vegetative stress and senescence of horticultural products. NO was initially regarded as an environmental pollutant, but since 1996, when emission of NO from plants was reported by Leshem and Haramaty, it has drawn much worldwide attention. The present study was performed to investigate the effect of NO fumigation on fruit ripening of harvested “Sui you 2” Carica papaya in relation to the postharvest quality and content of soluble sugars. Our results indicate that NO gas can be potentially applied for prolonging the storage life and delaying soluble sugar change of papaya fruit.

BACKGROUND: Biological control is a potential strategy to reduce post-harvest decay in several fruits. Little research has been carried out on the effects of endophytic bacterium on post-harvest blight caused by Phytophthora nicotianae in papaya. In this work, the biocontrol activity of Pseudomonas putida MGP1 on this disease and its possible mechanisms, including changes of defensive enzyme activities, total phenolic content and mRNA levels of two important genes, were investigated. RESULTS: Fruits treated with MGP1 showed a significant lower disease index and demonstrated increases in chitinase, β-1,3-glucanase, phenylalanine ammonia-lyase, peroxidase, polyphenol oxidase and catalase activities and total phenolic content. In addition, the expression levels of pathogenesis related protein 1 gene (PR1) and non-expressor of PR1 gene (NPR1) in papaya fruits were elevated by MGP1 treatment. CONCLUSION The results indicated that papaya fruits were responsive to the endophytic bacterium Ps. putida, which could activate defensive enzymes and genes and thereby induce host disease resistance. © 2012 Society of Chemical Industry

The plant-specific NAC (NAM, ATAF1/2, and CUC2) transcription factors (TFs) play important roles in plant growth, development, and stress responses. However, the precise role of NAC TFs in relation to fruit ripening is poorly understood. In this study, six NAC genes, designated MaNAC1–MaNAC6, were isolated and characterized from banana fruit. Subcellular localization showed that MaNAC1–MaNAC5 proteins localized preferentially to the nucleus, while MaNAC6 was distributed throughout the entire cell. A transactivation assay in yeast demonstrated that MaNAC4 and MaNAC6, as well as their C-terminal regions, possessed trans-activation activity. Gene expression profiles in fruit with four different ripening characteristics, including natural, ethylene-induced, 1-methylcyclopropene (1-MCP)-delayed, and a combination of 1-MCP with ethylene treatment, revealed that the MaNAC genes were differentially expressed in peel and pulp during post-harvest ripening. MaNAC1 and MaNAC2 were apparently upregulated by ethylene in peel and pulp, consistent with the increase in ethylene production. In contrast, MaNAC3 in peel and pulp and MaNAC5 in peel were constitutively expressed, and transcripts of MaNAC4 in peel and pulp and MaNAC6 in peel decreased, while MaNAC5 or MaNAC6 in pulp increased slightly during fruit ripening. Furthermore, the MaNAC2 promoter was activated after ethylene application, further enhancing the involvement of MaNAC2 in fruit ripening. More importantly, yeast two-hybrid and bimolecular fluorescence complementation analyses confirmed that MaNAC1/2 physically interacted with a downstream component of ethylene signalling, ethylene insensitive 3 (EIN3)-like protein, termed MaEIL5, which was downregulated during ripening. Taken together, these results suggest that MaNACs such as MaNAC1/MaNAC2, may be involved in banana fruit ripening via interaction with ethylene signalling components.

Pineapple (Ananas comosus (L.) Merr. cv. 'Paris') is sensitive to low temperature and highly susceptible to blackheart during cold storage, which causes serious fruit decay. This work investigated the effect of wax treatment (Sta-Fresh 2952, 60 g/L) on blackheart of pineapple under chilling stress. Wax treatment significantly reduced blackheart symptoms after 14 days of storage and markedly delayed changes in firmness and flesh color during the whole period of storage. The weight loss of wax-treated fruit (2.6%) was less than the control (3.1%) at the 24th day of storage. The treatment decreased the activities of PG and EGase for maintaining cell wall stability during the later period of storage. In the control fruit, the structure of flesh cells was significantly damaged under chilling stress, with looser cell wall, absence of middle lamella, loss of membrane integrity, and many cells near the vascular tissue collapsed. The subcellular elements could be barely observed in the control after storage. These destructive symptoms were significantly alleviated in the wax-treated fruit. The results suggest that wax treatment could reduce blackheart of pineapple under chilling stress via maintenance of cell integrity.

MYC2, a basic helix-loop-helix (bHLH) transcription factor, is a key regulator in the activation of jasmonate (JA) response. However, the molecular details of MYC2 involving in methyl jasmonate (MeJA)-induced chilling tolerance of fruit remain largely unclear. In the present work, two MYC2 genes, MaMYC2a and MaMYC2b, and one homolog of the inducer of the C-repeat-binding factor (CBF) gene, MaICE1 were isolated and characterized from banana fruit. MaMYC2s and MaICE1 were found to be all localized in the nucleus. In addition, the proline-rich domain (PRD) and the acidic domain (AD) in the N-terminus were important for the transcriptional activation of MaMYC2 in yeast cells. Unlike MaICE1's constitutive expression, MaMYC2a and MaMYC2b were induced rapidly following MeJA treatment during cold storage. Moreover, protein-protein interaction analysis confirmed that MaMYC2s interacted with MaICE1. The expression of ICE-CBF cold-responsive pathway genes including MaCBF1, MaCBF2, MaCOR1, MaKIN2, MaRD2 and MaRD5 was also significantly induced by MeJA. Taken together, our work provides strong evidence that MaMYC2 is involved in MeJA-induced chilling tolerance in banana fruit through physically interacting and likely functionally coordinating with MaICE1, revealing a novel mechanism for ICE1 in response to cold stress as well as during development of induced chilling tolerance.

An endophytic bacterium named Pseudomonas putida MGY2 was isolated from papaya fruit. The effect of MGY2 on reducing anthracnose caused by Colletotrichum gloeosporioides infection in harvested papaya fruit and the possible mechanisms involved were investigated. Fruit treated with MGY2 showed a significant lower disease index, disease incidence, and lesion diameter than the control. MGY2 reduced the decrease in firmness and delayed the peak of ethylene production of harvested papaya fruit stored at 25 °C. MGY2 also significantly enhanced the activities of phenylalanine ammonia-lyase (PAL), catalase (CAT), and peroxidase (POD) and increased the phenolic content. The expression levels of PAL1 , CAT1 , and POD genes were obviously elevated in MGY2-treated fruit. These results suggested that papaya fruit is capable of responding to the endophyte P. putida MGY2, which could activate defensive enzymes and genes and thereby induce host disease resistance.

BACKGROUND: Little attention has been paid to characterising the ethylene-signalling pathway genes in relation to abnormal ripening of harvested banana fruit during storage at high temperature. The aim of the present study was to investigate banana fruit abnormal ripening and the expression of ten genes associated with the ethylene-signalling pathway, namely MaACS1, MaACO1, MaERS1–4 and MaEIL1–4, at high temperature. Changes in these parameters of banana fruit at high temperature in response to 1-MCP pretreatment were also investigated. RESULTS: High temperature accelerated the decline in fruit firmness, increased ethylene production and inhibited degreening in banana fruit, resulting in fruit abnormal ripening. In addition, the expression of MaACS1, MaACO1, MaERS2, MaERS3, MaERS4, MaEIL1, MaEIL3 and MaEIL4 was enhanced in banana fruit stored at high temperature. However, application of 1-MCP prior to high temperature storage delayed fruit abnormal ripening and simultaneously suppressed the expression of MaACS1, MaERS2, MaERS3, MaEIL1, MaEIL3 and MaEIL4. CONCLUSION: The findings of this study suggested that the expression of genes associated with the ethylene-signalling pathway might be involved in banana fruit abnormal ripening at high temperature. Application of 1-MCP suppressed the expression of genes associated with the ethylene-signalling pathway, which may be attributed at least partially to 1-MCP delaying fruit abnormal ripening at high temperature. Copyright © 2010 Society of Chemical Industry

Three full-length cytosol small heat shock protein (sHSP) genes, including two class I sHSP (CI sHSP) and one class II sHSP (CII sHSP) cDNAs, termed Ps-CI sHSP1 , Ps-CI sHSP2 and Ps-CII sHSP1 respectively, were isolated and characterized from plum fruit at harvest. Their expression in relation to heat shock and cold acclimation-induced chilling tolerance were investigated. Heat shock treatment by dipping the fruit in water at 55 °C hot for 2 min and cold acclimation by conditioning the fruit at 8 °C for 5 d prior to storage at 2 °C could effectively reduce malondialdehyde (MDA) content and alleviate chilling injury. Furthermore, accumulation of Ps-CII sHSP1 mRNA transcripts in the fruit during the subsequent storage at 2 °C was remarkably enhanced by heat shock and cold acclimation treatments. These data suggest that heat shock and cold acclimation treatments induced the expression of Ps-CII sHSP1 , which may be involved in chilling tolerance of the fruit caused by these treatments.

BACKGROUND: Traditional approaches to the control of diseases of papaya fruit rely on the use of synthetic chemicals, which can cause serious human health and environmental problems. Endophytes might be used as an alternative to chemicals to effectively control diseases of harvested papaya fruit. RESULTS: MGP1 was one of the biological control agents that was selected from the pericarp of papaya and identified as Pseudomonas putida biovar A. The bacterium was able to colonise in the lamina, leafstalk, pericarp and pulp of papaya and strongly inhibit ten kinds of phytopathogen. Positive control effects were achieved when fruits were challenged with Phytophthora nicotianae at 24 and 48 h after MGP1 treatment. The control effect of MGP1 on anthracnose of harvested papaya fruit reached 54%. The application of MGP1 at five preharvest stages of papaya significantly reduced the disease index of anthracnose, with the best control effect reaching 63% after application at the florescence stage. However, the rate of latent infection of Colletotrichum gloeosporioides was significantly reduced only after application at the florescence stage. CONCLUSION: The results indicated the powerful ability of MGP1 as a biological agent. Copyright © 2009 Society of Chemical Industry

Background: C-repeat binding factors (CBFs) are transcription factors that regulate the expression of a number of genes related to abiotic stresses. Few CBF genes have been cloned from other plants but no report in papaya. In present study, a full-length cDNA, designated as CpCBF2 , was cloned from papaya using in silico cloning and 5’- rapid amplification cDNA ends (RACE). Sequence analysis was performed to understand the gene function. The expression pattern of CpCBF2 in papaya under low (7°C) and high temperature (35°C) stresses was examined using real-time quantitative polymerase chain reaction (RT-qPCR). Results: The full-length cDNA of CpCBF2 was 986-bp, with a 762-bp open reading frame (ORF) encoding a 254 amino acid polypeptide. CpCBF2 contained several major highly conserved regions including the CBF-family signature PKRRAGRKKFQETRHP and FADSAW in its amino acid sequence. Phylogenetic tree and three-dimensional structure analysis showed that CpCBF2 had a relatively close relationship with other plant CBFs. Gene expression analysis showed that high temperature stress had little effect on the expression of CpCBF2 but low temperature repressed CpCBF2 expression. Conclusion: The results showed that CpCBF2 may involve in different roles in temperature stress tolerance. This study provided a candidate gene potentially useful for fruit temperature stress tolerance, although its function still needs further confirmation.

Ethylene response factors (ERFs) play important roles in fruit development, ripening, defense responses and stress signaling pathways. After harvest, climacteric fruit such as papaya are subject to a range of problems associated with postharvest handling and storage treatments. There have been few attempts to evaluate the role of ERFs in fruit's responses to environmental stimuli. To investigate the transcriptional mechanisms underlying fruit developmental, ripening and stresses, we cloned four ERFs from papaya. The deduced amino acid sequence of CpERFs contained the conserved apetalous (AP2)/ERF domain, which shared high similarity with other reported AP2/ERF domains. The phylogeny, gene structures, and putatively conserved motifs in papaya ERF proteins were analyzed, and compared with those of Arabidopsis. Expression patterns of CpERFs were examined during fruit development, under 1-MCP treatment, ethephon treatment, biotic stress (temperature stress) and pathogen stress. CpERFs displayed differential expression patterns and expression levels under different experimental conditions. CpERF2 and CpERF3 showed a close association with fruit ripening and CpERFs had a high expression level in the earlier stages during the fruit development period. The expression of CpERFs strongly associated with stress response. These results support the role for papaya ERFs in transcriptional regulation of ripening-related or stress-respond genes and thus, in the regulation of papaya fruit-ripening processes and stress responses.

The wide angular range of the treelike structure in Morpho butterfly scales was investigated by finite-difference time-domain (FDTD)/particle-swarm-optimization (PSO) analysis. Using the FDTD method, different parameters in the Morpho butterflies' treelike structure were studied and their contributions to the angular dependence were analyzed. Then a wide angular range was realized by the PSO method from quantitatively designing the lamellae deviation (Δy), which was a crucial parameter with angular range. The field map of the wide-range reflection in a large area was given to confirm the wide angular range. The tristimulus values and corresponding color coordinates for various viewing directions were calculated to confirm the blue color in different observation angles. The wide angular range realized by the FDTD/PSO method will assist us in understanding the scientific principles involved and also in designing artificial optical materials.

Real-time reverse transcription PCR (RT-qPCR) is a preferred method for rapid and accurate quantification of gene expression studies. Appropriate application of RT-qPCR requires accurate normalization though the use of reference genes. As no single reference gene is universally suitable for all experiments, thus reference gene(s) validation under different experimental conditions is crucial for RT-qPCR analysis. To date, only a few studies on reference genes have been done in other plants but none in papaya. In the present work, we selected 21 candidate reference genes, and evaluated their expression stability in 246 papaya fruit samples using three algorithms, geNorm, NormFinder and RefFinder. The samples consisted of 13 sets collected under different experimental conditions, including various tissues, different storage temperatures, different cultivars, developmental stages, postharvest ripening, modified atmosphere packaging, 1-methylcyclopropene (1-MCP) treatment, hot water treatment, biotic stress and hormone treatment. Our results demonstrated that expression stability varied greatly between reference genes and that different suitable reference gene(s) or combination of reference genes for normalization should be validated according to the experimental conditions. In general, the internal reference genes EIF (Eukaryotic initiation factor 4A), TBP1 (TATA binding protein 1) and TBP2 (TATA binding protein 2) genes had a good performance under most experimental conditions, whereas the most widely present used reference genes, ACTIN (Actin 2), 18S rRNA (18S ribosomal RNA) and GAPDH (Glyceraldehyde-3-phosphate dehydrogenase) were not suitable in many experimental conditions. In addition, two commonly used programs, geNorm and Normfinder, were proved sufficient for the validation. This work provides the first systematic analysis for the selection of superior reference genes for accurate transcript normalization in papaya under different experimental conditions.

Three analytical methods, including headspace solid-phase microextraction (HS-SPME), liquid–liquid extraction (LLE) and steam distillation extraction (SDE), were utilized to investigate the aroma profile characteristics of Xinjiang oblate-peach fruit during storage, and the characterizing compounds were detected by gas chromatography mass spectrometry (GC-MS). Silica fiber coated with (DVB-CAR-PDMS) was found to be more efficient for collecting the SPME headspace volatile compounds, and the extraction time of 40 min was preferred in this study. The SPME headspace volatile constituents present in oblate-peach before and after 4 weeks of cold storage (4±1°C) have been analysed, while some physical characteristics such as fruitweight, firmness, soluble solids content (SSC), and titratable acid were monitored during storage. The results show that the volatile compounds displayed different composition during storage, a total of 58 volatiles were identified, 52 prior to storage and 45 after 4 week’s storage, the content of lactones and esters, characteristic compounds of peach aroma, were much lower after 4 weeks of storage. Thirteen of the pre-storage volatiles were not found after storage. Key words: Oblate-peaches, aroma, gas chromatography mass spectrometry (GC–MS),headspace solid-phase microextraction (HS-SPME), liquid–liquid extraction (LLE), steam distillation extraction (SDE).

Papaya (Carica papaya L.) is sensitive to low temperature and easy to be subjected to chilling injury, which causes fruit ripening disorder. This study aimed to investigate the relationship between the expression of genes related to ethylene and fruit ripening disorder caused by chilling injury. Papaya fruits were firstly stored at 7°C and 12°C for 25 and 30 days, respectively, then treated with exogenous ethylene and followed by ripening at 25°C for 5 days. Chilling injury symptoms such as pulp water soaking were observed in fruit stored at 7°C on 20 days, whereas the coloration and softening were completely blocked after 25 days, Large differences in the changes in the expression levels of twenty two genes involved in ethylene were seen during 7°C-storage with chilling injury. Those genes with altered expression could be divided into three groups: the group of genes that were up-regulated, including ACS1/2/3, EIN2, EIN3s/EIL1, CTR1/2/3, and ERF1/3/4; the group of genes that were down-regulated, including ACO3, ETR1, CTR4, EBF2, and ERF2; and the group of genes that were un-regulated, including ACO1/2, ERS, and EBF1. The results also showed that pulp firmness had a significantly positive correlation with the expression of ACS2, ACO1, CTR1/4, EIN3a/b, and EBF1/2 in fruit without chilling injury. This positive correlation was changed to negative one in fruit after storage at 7°C for 25 days with chilling injury. The coloring index displayed significantly negative correlations with the expression levels of ACS2, ACO1/2, CTR4, EIN3a/b, ERF3 in fruit without chilling injury, but these correlations were changed into the positive ones in fruit after storage at 7°C for 25 days with chilling injury. All together, these results indicate that these genes may play important roles in the abnormal softening and coloration with chilling injury in papaya.