Basic helix-loop-helix(bHLH)transcription factor MdbHLH3 negatively affects the storage performance of postharvest apple fruit

The storage period of fleshy fruits greatly affects their quality and selection,and is largely controlled by genetic factors.Therefore,it is imperative to elucidate how genetic factors affect fruit ripening and its storage.Here,we evaluated the postharvest storage properties of the basic helix-loop-helix(bHLH)transcription factor MdbHLH3-overexpressing transgenic Royal gala apple fruits.During storage,the contents of starch,malic acid,fructose,glucose,and sucrose in fruits of three MdbHLH3 transgenic lines were always higher than those of the wild-type(WT)control.Interestingly,the sugar-acid ratio also showed the same trend during fruit storage.Additionally,the fruit firmness decreased with increasing storage time,and the contents of cell wall components such as water-soluble pectin and cellulose in transgenic fruits were higher than those in control fruits,while the firmness of transgenic fruits was lower than that in WT control fruits.Though the ethylene release rate in both showed the same trend(firstly increasing,then decreasing,and finally peaking)in 90-day stored fruits,transgenic apples had higher ethylene levels than the WT control throughout storage.Furthermore,the activities of membrane peroxidase,antioxidant enzymes,and fruit ripening enzymes in all transgenic fruits were significantly higher than those in the WT control.Thus,our findings show how MdbHLH3 negatively regulates and reduces apple storage time.This may prove useful for not only developing biotechnological strategies,but also support traditional breeding programs,to help improve the storage time of fleshy fruits.

Effect of Modified Atmosphere Packaging (MAP) on the Stability of Anthocyanins and Degradation of Phenolic Compounds during Postharvest Storage of Pomegranate Fruit

Effects of storage temperature, packaging material, elevated CO2 and reduced O2 contents in the package headspace, and their interaction effects on the total content of anthocyanins and degradation of phenolic compounds during long storage of “Malase Torsh Saveh” pomegranate were studied. The study findings showed that only storage temperature and its duration had significant effects on the degradation of phenolic compounds. The content of anthocyanins was affected by the single effect of storage time and its 3-way interaction effect with the storage temperature and the fruit’s surrounding gas composition. Higher contents of both total anthocyanins and browning pigments were recorded at 2°C storage temperature. The Browning Index (BI) of the pomegranate extracts showed to change quadratically with the variations in the total anthocyanins content but linearly with the variations in the content of browning compounds. Thermal dipping treatment and its interaction with the storage time also had significant effect on the BI values of the extracts obtained from modified atmosphere packaged pomegranates stored at 6 °C.

Elicitation-Based Modulation of Shelf Life in Fruits: Physiological and Molecular Insights

The process of ripening involves physiological and biochemical events that become a concern during postharvest storage.We have documented different approaches for the preservation and maintenance of fruit quality during the postharvest period that are biocompatible and fully safe for consumption.Chemical residues that sustain sensory characteristics,such as color,flavor,aroma,and texture,are considered.In fruit ripening,both physical and chemical elicitors are described that regulate ethylene biosynthesis or its signaling for gene expression.The key regulatory enzymes,such as ACC synthase and ACC oxidase,for ethylene biosynthesis,are important for both climacteric and non-climacteric fruits.Anti-oxidizing genes that retain sensory characteristics are concerns in this respect.Chemical elicitors,including chitosan,polyamine,phenolics,lipopolysaccharide,silver derivatives,and nanocomposites,are described.Gas pressure,light wavelengths,relative humidity,cooling,and other environmental factors are important for improved postharvest storage.These elicitors maintain redox status by inhibiting the generation of reactive oxygen species(ROS)or their lysis.Growth regulators,including abscisic acid,auxin,brassinosteroids,jasmonic acid,and salicylic acid,are important for the regulation of ripening.Mechanical injuries,ionic imbalances,temperature variations,and tissue dehydration can occur irrespective of ripening cate-gories.The use of synthetic physiochemically active compounds is discussed in terms of physiological,metabolic,cellular,and molecular functions.Ethylene-induced autocatalytic processes,antioxidant cascades,epigenetic regulation,and homeodomain gene expression are discussed.Sugar–acid metabolism,dissolution of the cell wall,and direct or indirect production of secondary metabolites related to postharvest storage are mentioned regarding chilling storage.Elicitors and agrochemicals that trigger plant defense to increase secondary metabolite production are discussed for reducing fruit senescence during postharvest storage.

Effects of nitric oxide treatment on flavour compounds and antioxidant enzyme activities of button mushroom (Agaricus bisporus) during storage

Button mushroom(Agaricus bisporus)is sold well for its unique flavour and nutritional benefits.However,the mushroom flavour deteriorates quickly during storage because of its delicate structure and high moisture.In this study,the effects of nitric oxide(NO)application on flavour compounds and antioxidant enzyme activities of stored button mushrooms were investigated.The button mushrooms were immersed in the NO donor sodium nitroprusside(15μmol/L)for 3 min and then stored under the condition of 4℃,90%relative humidity for 12 days.Results showed that the treated mushrooms have reduced weight loss rate,uniform white colour,and higher firmness during storage.Compared to the control,the ketones,alcohols,esters,and aldehydes in the NO-treated button mushroom increased sharply at 3 days of storage and then showed a continuing decline trend,except ester compounds which reached the peak value at 6 days of storage.In addition,NO treatment increased the total phenolics and catalase activity and inhibited the polyphenol oxidase activity in the stored button mushroom.These results indicated that NO treatment is an alternative storage technology to enhance antioxidant capacity and maintain flavour and consumer acceptance of stored button mushroom.

Integrative Analysis of Transcriptome and Phenolic Compounds Profile Provides Insights into the Quality of Soursop (Annona muricata L.) Fruit

Soursop(Annona muricata L.)is a tropical fruit highly valued for its uniqueflavor,nutritional value,and health-promoting properties.The ripening process of soursop involves complex changes in gene expression and metabo-lite accumulation,which have been studied using various omics technologies.Transcriptome analysis has provided insights into the regulation of key genes involved in ripening,while metabolic compound analysis has revealed the presence of numerous bioactive compounds with potential health benefits.However,the integration of transcrip-tome and metabolite compound data has not been extensively explored in soursop.Therefore,in this paper,we present a comprehensive analysis of the transcriptome and phenolic compound profiles of soursop during ripen-ing.The integration analysis showed that the genes and phenolic compounds were mainly involved in the starch and sucrose metabolism pathways during soursop ripening.Further,the phenolic compounds Kaempferol 3-Q-galactoside,Procyanidin C1,Procyanidin trimmer C1,and m-Coumaric,as well as the genes Ubiquitin-like protein 5(UBL5_ARATH),ATP-dependent zinc metalloprotease FTSH8(FTSH8_ORYSJ),Zinc transporter 4(ZIP4_AR-ATH),Thioredoxin-like 3-1(TRL31_ORYSJ),Mitogen-activated protein kinase YODA(YODA_ARATH),R-man-delonitrile lyase-like(MGL_ARATH),26s protease regulatory subunit 6A homolog(PRS6_SOLLC),Cytochrome P45072A13(C7A13ARATH),Cytochrome P45084A1(C84A1_ARATH)and Homoserine O-trans-acetylase(MET2-ORYSJ)were correlated and differentially accumulated and expressed,respectively.Our study provides new insights into the molecular mechanisms underlying soursop ripening and may contribute to the development of strategies for improving the nutritional quality and shelf life of this important fruit.