Geographical origin identification of winter jujube(Ziziphus jujuba Dongzao')by using multi-element fingerprinting with chemometrics

Winter jujube(Ziziphus jujuba'Dongzao')is greatly appreciated by consumers for its excellent quality,but brand infringement frequently occurs in the market.Here,we first determined a total of 38 elements in 167 winter jujube samples from the main winter jujube producing areas of China by inductively coupled plasma mass spectrometer(ICP-MS).As a result,16 elements(Mg,K,Mn,Cu,Zn,Mo,Ba,Be,As,Se,Cd,Sb,Ce,Er,Tl,and Pb)exhibited significant differences in samples from different producing areas.Supervised linear discriminant analysis(LDA)and orthogonal projection to latent structures discriminant analysis(OPLS-DA)showed better performance in identifying the origin of samples than unsupervised principal component analysis(PCA).LDA and OPLS-DA had a mean identification accuracy of 87.84 and 94.64%in the testing set,respectively.By using the multilayer perceptron(MLP)and C5.0,the prediction accuracy of the models could reach 96.36 and 91.06%,respectively.Based on the above four chemometric methods,Cd,Tl,Mo and Se were selected as the main variables and principal markers for the origin identification of winter jujube.Overall,this study demonstrates that it is practical and precise to identify the origin of winter jujube through multi-element fingerprint analysis with chemometrics,and may also provide reference for establishing the origin traceability system of other fruits.

Lipidomic and transcriptomic analysis reveals reallocation of carbon flux from cuticular wax into plastid membrane lipids in a glossy“Newhall”navel orange mutant

Both cuticle and membrane lipids play essential roles in quality maintenance and disease resistance in fresh fruits.Many reports have indicated the modification of alternative branch pathways in epicuticular wax mutants;however,the specific alterations concerning lipids have not been clarified thus far.Here,we conducted a comprehensive,timeresolved lipidomic,and transcriptomic analysis on the“Newhall”navel orange(WT)and its glossy mutant(MT)“Gannan No.1”.The results revealed severely suppressed wax formation accompanied by significantly elevated production of 36-carbon plastid lipids with increasing fruit maturation in MT.Transcriptomics analysis further identified a series of key functional enzymes and transcription factors putatively involved in the biosynthesis pathways of wax and membrane lipids.Moreover,the high accumulation of jasmonic acid(JA)in MT was possibly due to the need to maintain plastid lipid homeostasis,as the expression levels of two significantly upregulated lipases(CsDAD1 and CsDALL2)were positively correlated with plastid lipids and characterized to hydrolyze plastid lipids to increase the JA content.Our results will provide new insights into the molecular mechanisms underlying the natural variation of plant lipids to lay a foundation for the quality improvement of citrus fruit.

Integrated multi-omics analysis of developing‘Newhall’orange and its glossy mutant provide insights into citrus fragrance formation

Sesquiterpene valencene is dominant in flavedo tissues of sweet oranges and imparts a unique woody aroma.However,the interaction between the biosynthetic pathways of valencene and other nutritional compounds is less studied.Sesquiterpenoids were significantly accumulated in a previously reported glossy mutant of orange(MT)than the wild type(WT),especially valencene and caryophyllene.In addition,we identified several other pathways with variations at both the transcriptional and metabolic levels in MT.It’s interesting to found those upregulated metabolites in MT,such as eukaryotic lipids,kaempferol and proline also showed strong positive correlation with valencene along with fruit maturation while those down-regulated metabolites,such as phenylpropanoid coumarins and most of the modified flavonoids exhibited negative correlation.We then categorized these shifted pathways into the‘sesquitepenoid-identical shunt’and the sesquitepenoid-opposite shunt’and confirmed the classification result at transcriptional level.Our results provide important insights into the connections between various fruit quality-related properties.

Identification of key gene networks controlling monoterpene biosynthesis during grape ripening by integrating transcriptome and metabolite profiling

Monoterpenes are typical aroma components of muscat grape cultivars,providing pleasant floral and fruity aromas to grapes and wines.However,the molecular mechanism of monoterpene biosynthesis between muscat and non-muscat grape remains unclear.Here,the muscat grape cultivar‘Jumeigui’and the non-muscat grape cultivar‘Kyoho’were chosen as plant materials for a comprehensive transcriptome and metabolite analysis.The gas chromatography-mass spectrometry(GC-MS)analysis demonstrated that a total of 27 and 23 monoterpene compounds were identified and quantified in the‘Jumeigui’and‘Kyoho’grape,respectively.‘Jumeigui’grape accumulated significantly higher concentrations of monoterpenes than‘Kyoho’grape.Furthermore,geraniol,linalool,geranic acid,and β-citronellol might be important odorants contributing to the floral character of the‘Jumeigui’grape due to the high levels odor activity values(OAVs).Transcriptome analysis demonstrated that the expression profiles of VvDXS,VvGGPPS.SSU1,Vv TPS-b/g showed a positive correlation with monoterpene accumulation in grapes.In addition,the expression patterns of the genes involved in jasmonic acid(JA)synthesis and signal were also positively correlated with monoterpene accumulation.All these results will help guide the functional verification of candidate genes related to monoterpene biosynthesis,as well as identify the master transcriptional and hormonal regulators of this pathway in grapes.

Transcription factor CsESE3 positively modulates both jasmonic acid and wax biosynthesis in citrus

PLIP lipases can initiate jasmonic acid(JA)biosynthesis.However,little is known about the transcriptional regulation of this process.In this study,an ERF transcription factor(CsESE3)was found to be co-expressed with all necessary genes for JA biosynthesis and several key genes for wax biosynthesis in transcriptomes of‘Newhall’navel orange.CsESE3 shows partial sequence similarity to the well-known wax regulator SHINEs(SHNs),but lacks a complete MM protein domain.Ectopic overexpression of CsESE3 in tomato(OE)resulted in reduction of fruit surface brightness and dwarf phenotype compared to the wild type.The OE tomato lines also showed significant increases in the content of wax and JA and the expression of key genes related to their biosynthesis.Overexpression of CsESE3 in citrus callus and fruit enhanced the JA content and the expression of JA biosynthetic genes.Furthermore,CsESE3 could bind to and activate the promoters of two phospholipases from the PLIP gene family to initiate JA biosynthesis.Overall,this study indicated that CsESE3 could mediate JA biosynthesis by activating PLIP genes and positively modulate wax biosynthesis.The findings provide important insights into the coordinated control of two defense strategies of plants represented by wax and JA biosynthesis.