CRISPR/Cas9-mediated SNAC9 mutants reveal the positive regulation of tomato ripening by SNAC9 and the mechanism of carotenoid metabolism regulation

NAC transcriptional regulators are crucial for tomato ripening.Virus-induced gene silencing(VIGS)of SNAC9(SlNAC19,Gene ID:101248665)affects tomato ripening,and SNAC9 is involved in ethylene and abscisic acid(ABA)metabolic pathways.However,the function of SNAC9 in pigment metabolism in tomatoes remains unclear.This work seeks to discover the mechanism of SNAC9 involvement in pigment metabolism during tomato ripening by establishing a SNAC9 knockout model using CRISPR/Cas9 technology.The results indicated that fruit ripening was delayed in knockout(KO)mutants,and SNAC9 mutation significantly affected carotenoid metabolism.The chlorophyll(Chl)degradation rate,total carotenoid content,and lycopene content decreased significantly in the mutants.The transformation rate of chloroplasts to chromoplasts in mutants was slower,which was related to the carotenoid content.Furthermore,SNAC9 changed the expression of critical genes(PSY1,PDS,CRTISO,Z-ISO,SGR1,DXS2,LCYE,LCYB,and CrtR-b2)involved in pigment metabolism in tomato ripening.SNAC9 knockout also altered the expression levels of critical genes involved in the biosynthesis of ethylene and ABA.Accordingly,SNAC9 regulated carotenoid metabolism by directly regulating PSY1,DXS2,SGR1,and CrtR-b2.This research provides a foundation for developing the tomato ripening network and precise tomato ripening regulation.

Effects of Exogenous Trehalose on the Metabolism of Sugar and Abscisic Acid in Tomato Seedlings Under Salt Stress

Salt stress a ects the growth and development of plants, which results in a decrease in crop quality and yield. In this study, we used tomato seedlings treated with salt and trehalose as experimental materials and analyzed them using the technique for order preference by similarity to ideal solution analysis to select the optimal trehalose concentration for treatment. We also determined the contents of sugar and abscisic acid (ABA) and detected the expression of genes involved in the metabolism of sugar and ABA by quantitative real-time PCR. Results showed that the optimal trehalose concentration was 2 mmol/L for tomato seedlings under salt stress. Exogenous trehalose decreased the starch content and increased the soluble sugar con- tent by a ecting the expression of genes related to the metabolism of starch and soluble sugar. Exogenous trehalose altered the accumulation and distribution of sugar by inducing the upregulation of sugar transporter genes. Furthermore, trehalose increased the ABA content to induce salt stress response by regulating the expression of genes related to the synthesis and metabolism of ABA. In conclusion, trehalose can e ectively alleviate salt stress and enhance salt tolerance of tomato. These ndings provide a novel perspective and a better resource to investigate the salt tolerance mechanism and a new method for alleviating salt stress in tomato.

Changes in Sugar Metabolism and Fruit Quality of Different Pear Cultivars During Cold Storage

This study evaluated the changes in sugar metabolism and fruit quality of diff erent pear cultivars during cold storage using seven major commercial pear cultivars belonging to diff erent Pyrus species, such as P. bretschneideri Rehd.("Huangguan,""Yali"), P. pyrifolia Nakai.("Wonhwang,""Hosui"), P. ussuriensis Maxim.("Jingbai,""Nanguo"), and P. communis L.("Bartlett"). The fi rmness, respiration rate, titratable acidity, total soluble solids, sugar content, and enzyme activity of the seven pear cultivars were investigated. SPSS was used for analyzing the signifi cance of diff erent indexes. Results showed that fructose was the dominant sugar, accounting for > 60% of total sugars, followed by glucose and sucrose. The respiration peak of almost all cultivars appeared within 60 days. The levels of fructose, glucose, sucrose, and total soluble solids increased within 90 days and then generally decreased. Acid invertase showed the highest activity among all pear cultivars, followed by neutral invertase, sucrose synthetase, and sucrose phosphate synthetase during storage.

Gene Expression and Activity of Enzymes Involved in Sugar Metabolism and Accumulation During “Huangguan” and “Yali” Pear Fruit Development

Since the carbohydrate content affects pear flavor during the process of growth, it is necessary to determine the sugar components that accumulate in the fruit. We analyzed the fruit carbohydrate content, and the gene expression and activity ofacid invertase(AI), neutral invertase(NI), sucrose synthase(SS), and sucrose phosphate synthase(SPS) during the development of "Huangguan" and "Yali" pears. The results demonstrate that during development, the fruit sugar metabolism of the "Huangguan" pear follows a typical sorbitol–starch-soluble sugars middle model, whereas the "Yali" pear fruit follows a typical sorbitol–sucrose–starch-soluble sugars middle model. In the "Huangguan" pear, we found the AI and NI gene expressions, as well as AI( P < 0.05) and NI( P < 0.01) enzyme activities, to be positively correlated, whereas we found the NI gene expression and NI enzyme activity of "Yali" pear to be negatively correlated( P < 0.01). We observed the high levels oflate-stage AI and early-stage SS during development to roughly correspond with the gene expression found in the late and early stages, respectively, suggesting their potential regulatory roles in "Huangguan" pear fruit development. Our results indicate that the primary function of SPS during the early developmental stage is to accumulate sucrose, whereas the primary function of AI is to promote hexose accumulation during the late developmental stage ofmature "Yali" pear fruit.

Radical-scavenging activity,ACE-inhibiting capability and identification of rapeseed albumin hydrolysate

Albumin derived from rapeseed was hydrolyzed sequentially using alcalase and flavorzyme to produce antioxidant peptides.To identify antioxidant peptides,rapeseed albumin hydrolysate(RAH)was fractionated using size exclusion chromatography(G-25).The antioxidant activity and angiotensin I-converting enzyme(ACE)inhibiting activity of rapeseed peptides(RSP)purified from RAH were evaluated.The results revealed that RSP-4 had the highest ABTS radical-scavenging activity(TEAC value=0.24)and ACE-inhibiting capacity(IC50=0.19 mg/mL)compared to other fractions.Moreover,RSP-4 was identified as PFDSYFVC(977 D)by electrospray ionization(ESI)mass spectrometry and tandem mass spectrometry(MS/MS).©2013 Beijing Academy of Food Sciences.Production and hosting by Elsevier B.V.All rights reserved.

Low-Rank and Sparse Representation with Adaptive Neighborhood Regularization for Hyperspectral Image Classification

Low-Rank and Sparse Representation(LRSR)method has gained popularity in Hyperspectral Image(HSI)processing.However,existing LRSR models rarely exploited spectral-spatial classification of HSI.In this paper,we proposed a novel Low-Rank and Sparse Representation with Adaptive Neighborhood Regularization(LRSR-ANR)method for HSI classification.In the proposed method,we first represent the hyperspectral data via LRSR since it combines both sparsity and low-rankness to maintain global and local data structures simultaneously.The LRSR is optimized by using a mixed Gauss-Seidel and Jacobian Alternating Direction Method of Multipliers(M-ADMM),which converges faster than ADMM.Then to incorporate the spatial information,an ANR scheme is designed by combining Euclidean and Cosine distance metrics to reduce the mixed pixels within a neighborhood.Lastly,the predicted labels are determined by jointly considering the homogeneous pixels in the classification rule of the minimum reconstruction error.Experimental results based on three popular hyperspectral images demonstrate that the proposed method outperforms other related methods in terms of classification accuracy and generalization performance.

Biochanin A and CPe-Ⅲ Peptide Improved Hepatic Infl ammation by Regulating the Hepatic Lipid Metabolic Pathways in Diet-Induced Obese Mice

Biochanin A(BCA) and CPe-Ⅲ peptide, which both exist in chickpea(Cicer arietinum L.), possess significant antihyperlipidemic properties. However, the actualmechanisms ofthose compounds in inhibiting the dysregulation oflipid metabolism and complicated inflammation have not been wellcharacterized. This study investigated the effects ofBCA, CPe-Ⅲ peptide, and combined BCA and CPe-Ⅲ peptide(BC) on the expression ofgenes involved in hepatic lipid and inflammation metabolism. Results demonstrated that BCA, CPe-Ⅲ peptide, and BC significantly attenuated hepatitis and hyperlipidemia by downregulating those genes involved in pro-inflammatory cytokines(TNF-α), hepatic fatty acid(FA) synthesis(ACC1 and FAS), cholesterolmetabolism(SREBP2, HMGCR, and PCSK9), and upregulating key regulators involved in FA oxidation(PPARα and FABP1), lipolysis(ATGL), LDLR, reverse cholesteroltransport(ABCA1, SR-B1, and LXRα), and cholesterolcatabolism(CYP7 A1). Moreover, they also altered the expression oflipid metabolism-related proteins, including SREBP2, PCSK9, LDLR, ABCA1, and CYP7 A1. Finally, these results revealed that the combination treatment ofBCA and CPe-Ⅲ peptide resulted in greater antihyperlipidemic activity compared with individualcompounds.

Effects of Edible Coatings on Quality and Antioxidant Activity of Zizyphus Jujuba Miller cv. Dongzao During Storage

The development of edible coatings has been lauded with respect to their safety and effectiveness.In this study,we researched the effects of edible coatings(2%CaCl_2,1%chitosan and 1%pullulan) on the nutrient content and antioxidant abilities of jujube(Zizyphus jujuba Miller cv.Dongzao).Using the new analysis technique for order of preference by similarity to ideal solution(TOPSIS),we evaluated the effects of these coatings.Compared with the control fruit group,test results showed that coating treatment significantly delayed fruit senescence.Specifically,CaCl_2 treatment not only maintained fruit storage quality and antioxidant activity but also restrained the production and accumulation of malondialdehyde in jujube.Chitosan treatment delayed decreases in secondary metabolites and superoxide dismutase and catalase activity.Pullulan coatings performed better in terms of proanthocyanidin and cyclic adenosine monophosphate(cAMP).We also used TOPSIS to evaluate the preservation effect of different film coatings and found 2%CaCl_2 to be the best treatment for jujube,followed by 1%chitosan and 1%pullulan.Based on the appropriate materials and concentration of the film coatings,edible coatings have the potential to retain the quality and antioxidant capacity of the Chinese jujube cv.Dongzao.

Investigating Interaction Between Biochanin A and Human Serum Albumin by Multi-spectroscopic and Molecular Simulation Methods

Biochanin A(BCA), the most abundant isoflavone in chickpeas, presents a wide range of biological activities, such as hypolipidaemic, anti-oxidative, antiproliferative, and estrogen-like effects. We investigated the interaction between BCA and human serum albumin(HSA) via several techniques. UV–Vis absorption spectroscopy verified the conformational variation of HSA after BCA addition, and fluorescence spectroscopy revealed the relevant binding parameters. Circular dichroism spectroscopy was used to estimate the secondary structural changes of HSA with and without BCA. Molecular docking and dynamics simulations were then applied to study the characteristics of HSA with BCA. Energy decomposition analysis was used to prove that Trp214 in subdomain ⅡA of HSA is the most likely binding site of BCA. Van der Waals forces and hydrophobic interactions may play important roles during the binding process. All of our results showed that BCA presents significant binding affinity to HSA, thus confirming that the role of HSA has as an efficient transporter of biomolecules.

Transcriptome Profiling of Abscisic Acid-Related Pathways in SNAC4/9-Silenced Tomato Fruits

The NAC(NAM,ATAF,and CUC)family is considered one of the largest families of plant transcription factor,and its members are involved in fruit ripening.Abscisic acid(ABA)has been demonstrated to modulate the fruit ripening process.By applying the virus-induced gene silencing method and next-generation sequencing technology,we conducted a compara-tive analysis of the eff ects of SNAC4(SlNAC48,accession number:NM 001279348.2)and SNAC9(SlNAC19,accession number:XM 004236996.2)on tomato fruit ripening.The results of high-throughput sequencing identified 1262 significant(p<0.05)diff erentially expressed genes(DEGs)in SNAC4-silenced fruit compared to control fruit,while 655 DEGs were identified in SNAC9-silenced fruit.In addition,we selected 26 and 30 significant DEGs(p<0.05 and log 2-fold change>1.0)related to ABA in SNAC4-silenced and SNAC9-silenced tomatoes,respectively,for further analysis.The XET gene and two other genes(E8 and EXP1)were significantly down and upregulated in SNAC4-silenced tomatoes,respectively.However,the PYL9 gene and four other genes(PP2C,CYP707A2,EXPA6,and ACS6)were significantly down and upregulated in SNAC9-silenced tomatoes,respectively.In addition,ten DEGs were selected for use in tests to confirm the accuracy of the transcriptomic results by quantitative real-time polymerase chain reaction(qRT-PCR).Our results highlight the relationship between SNAC4/9 and ABA in the regulation of tomato ripening,which may help provide a theoretical basis for further research on the mechanisms of tomato fruit ripening and senescence.

Spatio-temporal analysis of phenology in Yangtze River Delta based on MODIS NDVI time series from 2001 to 2015

Phenology has become a good indicator for illustrating the long-term changes in the natural resources of the Yangtze River Delta.However,two issues can be observed from previous studies.On the one hand,existing time-series classification methods mainly using a single classifier,the discrimination power,can become deteriorated due to fluctuations characterizing the time series.On the other hand,previous work on the Yangtze River Delta was limited in the spatial domain (usually to 16 cities)and in the temporal domain (usually 2000-2010).To address these issues,this study attempts to analyze the spatiotemporal variation in phenology in the Yangtze River Delta (with 26 cities,enlarged by the state council in June 2016), facilitated by classifying the land cover types and extracting the phenological metrics based on Moderate Resolution Imaging Spectrometer (MODIS)Normalized Difference Vegetation Index (NDVI)time series collected from 2001 to 2015.First,ensemble learning (EL)-based classifiers are used for land cover classification,where the training samples (a total of 201,597)derived from visual interpretation based on GlobelLand30 are further screened using vertex component analysis (VCA),resulting in 600 samples for training and the remainder for validating. Then,eleven phenological metrics are extracted by TIMESAT (a package name)based on the time series, where a seasonal-trend decomposition procedure based on loess (STL-decomposition)is used to remove spikes and a Savitzky-Golay filter is used for filtering.Finally,the spatio-temporal phenology variation is analyzed by considering the classification maps and the phenological metrics.The experimental results indicate that:1)random forest (R.F)obtains the most accurate classification map (with an overall accuracy higher than 96%);2)different land cover types illustrate the various seasonalities;3)the Yangtze River Delta has two obvious regions,i.e.,the north and the south parts,resulting from different rainfall, temperature,and ecosystem conditions;4)the phenology variation over time is not significant in the study area;5)the correlation between gross spring greenness (GSG) and gross primary productivity (GPP)is very high, indicating the potential use of GSG for assessing the carbon flux.

Antioxidant and antitumor effects and immunomodulatory activities of crude and purified polyphenol extract from blueberries

The antioxidant and antitumor effects as well as the immunomodulatory activities of crude and purified polyphenol extract from blueberries were investigated. The antioxidant and antitumor effects of the polyphenol extract were measured both in vitro and in vivo, and their effect on the immune systems of CD-1 tumor-bearing mice were also analyzed. In vitro assays demonstrated that blueberry purified polyphenol extract （BBPP） exhibited higher antioxidant activities than blueberry crude polyphenol extract （BBCP）, but the opposite effect was observed in vivo. Both the in vitro and in vivo antitumor activity and the immunity assay showed that BBCP not only inhibited tumor growth, but also significantly improved the immunity of the mice. According to physical and histological studies, the CD-1 tumor-bearing mice treated with the polyphenol extract, especially high doses of BBCP experienced a higher quality of life than the positive control group （treated with cyclophosphamide）. These results indicate that BBCP has significant antioxidant and antitumor activities and that it can enhance the immunity of CD-1 tumor-bearing mice.

EXTRACTION AND EVALUATION OF EDIBLE OIL FROM SCHIZOCHYTRIUM SP.USING AN AQUEOUS ENZYMATIC METHOD

Schizochytrium sp.,a marine microalga,is a potential source of edible oil due to its short growth cycle and rapid lipid accumulation,especially of docosahexaenoic acid.An approach to isolate edible microalgal oil from Schizochytrium sp.using aqueous enzymatic extraction(AEE)was developed.Parameters were optimized by single-factor experiments followed by Box-Behnken design.Proteases were effective in extracting oil.The maximum free oil recovery(49.7%±0.58%)and total oil recovery(68.1%±0.94%)were obtained under optimum conditions of liquid-to-solid ratio of 4.8:1,a 2.5%enzyme concentration of papain and an extraction time of 2.2 h.There was a significant difference(P<0.05)in polyunsaturated fatty acid composition between microalgal oil obtained by AEE and by Soxhlet extraction,with the former having superior physiochemical properties and higher concentrations of bioactive components including total phenolic compounds and total tocopherols.These findings indicate a potential application of AEE for extraction of oil from Schizochytrium sp.