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This research explored the effects of using Accentuated Cut Edges (ACE) and macerating enzymes on the aroma and sensory profile of Marquette red wines after nine months of aging. The aroma analysis was conducted using gas chromatography-mass spectrometry (GC-MS) with solid-phase microextraction (SPME). The intensity of basic sensory attributes, including color, aroma, taste, and mouthfeel, were evaluated by eight trained panelists through descriptive analysis using 15 cm line scales. ACE treatment affected the aroma compounds profile, as suggested by the increased response ratio of ethyl butanoate, ethyl 2-methylpropanoate, and ethyl 3-methylbutanoate. Statistically, it significantly intensified honey (by 1.6 times) and green apple (by 2.1 times) notes, as perceived by panelists, compared to the control during the sensory descriptive analysis. Regardless of the type of enzymes, combined ACE and enzymes treatment amplified the color intensity of wine by up to 71.4% as observed by panelists, though this was not captured by spectrophotometric measurements (p > 0.05) from the previous study. A lower concentration of ester-derived compounds was found in ACE with enzymes wines, which was associated with the lower intensity of fruity notes during the descriptive analysis. Notably, none of the treatments affected astringency perception, likely due to the low concentration and small molecular weight of condensed tannins, alongside changes in the composition of soluble polysaccharide in Marquette red wines. [ABSTRACT FROM AUTHOR]

This study investigates the molecular mechanisms underlying fruit cracking in Akebia trifoliata, a phenomenon that significantly impacts fruit quality and marketability. Through comprehensive physiological, biochemical, and transcriptomic analyses, we identified key changes in cell wall components and enzymatic activities during fruit ripening. Our results revealed that ventral suture tissues exhibit significantly elevated activities of polygalacturonase (PG) and β-galactosidase compared to dorsoventral line tissues, indicating their crucial roles in cell wall degradation and structural weakening. The cellulose content in VS tissues peaked early and declined during ripening, while DL tissues maintained relatively stable cellulose levels, highlighting the importance of cellulose dynamics in fruit cracking susceptibility. Transcriptomic analysis revealed differentially expressed genes (DEGs) associated with pectin biosynthesis and catabolism, cell wall organization, and oxidoreductase activities, indicating significant transcriptional regulation. Key genes like AKT032945 (pectinesterase) and AKT045678 (polygalacturonase) were identified as crucial for cell wall loosening and pericarp dehiscence. Additionally, expansin-related genes AKT017642, AKT017643, and AKT021517 were expressed during critical stages, promoting cell wall loosening. Genes involved in auxin-activated signaling and oxidoreductase activities, such as AKT022903 (auxin response factor) and AKT054321 (peroxidase), were also differentially expressed, suggesting roles in regulating cell wall rigidity. Moreover, weighted gene co-expression network analysis (WGCNA) identified key gene modules correlated with traits like pectin lyase activity and soluble pectin content, pinpointing potential targets for genetic manipulation. Our findings offer valuable insights into the molecular basis of fruit cracking in A. trifoliata, laying a foundation for breeding programs aimed at developing crack-resistant varieties to enhance fruit quality and commercial viability. [ABSTRACT FROM AUTHOR]

BACKGROUND: Mango fruits undergo numerous postharvest quality losses during storage. Hence, the present study aimed to increase the shelf life of mango fruits by applying hexanal‐based enhanced freshness formulations (EFF) in combination with hot water treatment (HWT). RESULTS: The findings revealed that, among all the tested applications, the combination of EFF 1.0% + HWT reduced the weight loss, decay incidence, and activity of cell wall degrading enzymes of mango fruits. Also, the combined treatment was effective in maintaining the fruit quality parameters such as soluble solid contents, titratable acidity, ascorbic acid and activity of antioxidant compounds. CONCLUSION: The present study concludes that the postharvest application of EEF 1.0% in combination with HWT can be used in extending the shelf life of mango cv. 'Langra,' fruits stored at 12° C and 85–90% relative humidity for 35 days. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

SUMMARY: Chilling stress causes banana fruit softening disorder and severely impairs fruit quality. Various factors, such as transcription factors, regulate fruit softening. Herein, we identified a novel regulator, MaC2H2‐IDD, whose expression is closely associated with fruit ripening and softening disorder. MaC2H2‐IDD is a transcriptional activator located in the nucleus. The transient and ectopic overexpression of MaC2H2‐IDD promoted "Fenjiao" banana and tomato fruit ripening. However, transient silencing of MaC2H2‐IDD repressed "Fenjiao" banana fruit ripening. MaC2H2‐IDD modulates fruit softening by activating the promoter activity of starch (MaBAM3, MaBAM6, MaBAM8, MaAMY3, and MaISA2) and cell wall (MaEXP‐A2, MaEXP‐A8, MaSUR14‐like, and MaGLU22‐like) degradation genes. DLR, Y1H, EMSA, and ChIP‐qPCR assays validated the expression regulation. MaC2H2‐IDD interacts with MaEBF1, enhancing the regulation of MaC2H2‐IDD to MaAMY3, MaEXP‐A2, and MaGLU22‐like. Overexpressing/silencing MaC2H2‐IDD in banana and tomato fruit altered the transcript levels of the cell wall and starch (CWS) degradation genes. Several differentially expressed genes (DEGs) were authenticated between the overexpression and control fruit. The DEGs mainly enriched biosynthesis of secondary metabolism, amino sugar and nucleotide sugar metabolism, fructose and mannose metabolism, starch and sucrose metabolism, and plant hormones signal transduction. Overexpressing MaC2H2‐IDD also upregulated protein levels of MaEBF1. MaEBF1 does not ubiquitinate or degrade MaC2H2‐IDD. These data indicate that MaC2H2‐IDD is a new regulator of CWS degradation in "Fenjiao" banana and cooperates with MaEBF1 to modulate fruit softening, which also involves the cold softening disorder. Significance Statement: MaC2H2‐IDD/MaEBF1 complex modulates banana fruit softening by regulating genes related to starch and cell wall degradation. Chilling stress severely represses the activation of softening‐related genes, causing fruit ripening disorder and impairing the texture quality. [ABSTRACT FROM AUTHOR]

Abstract Enzymatic degradation of algae cell wall carbohydrates by microorganisms is under increasing investigation as marine organic matter gains more value as a sustainable resource. The fate of carbon in the marine ecosystem is in part driven by these degradation processes. In this study, we observe the microbiome dynamics of the macroalga Fucus vesiculosus in 25-day-enrichment cultures resulting in partial degradation of the brown algae. Microbial community analyses revealed the phylum Pseudomonadota as the main bacterial fraction dominated by the genera Marinomonas and Vibrio. More importantly, a metagenome-based Hidden Markov model for specific glycosyl hydrolyses and sulphatases identified Bacteroidota as the phylum with the highest potential for cell wall degradation, contrary to their low abundance. For experimental verification, we cloned, expressed, and biochemically characterised two α-L-fucosidases, FUJM18 and FUJM20. While protein structure predictions suggest the highest similarity to a Bacillota origin, protein–protein blasts solely showed weak similarities to defined Bacteroidota proteins. Both enzymes were remarkably active at elevated temperatures and are the basis for a potential synthetic enzyme cocktail for large-scale algal destruction.

Abstract Background Guava is a fruit prone to rapid spoilage following harvest, attributed to continuous and swift physicochemical transformations, leading to substantial postharvest losses. This study explored the efficacy of xanthan gum (XG) coatings applied at various concentrations (0.25, 0.5, and 0.75%) on guava fruits (Gola cultivar) over a 15-day storage period. Results The results indicated that XG coatings, particularly at 0.75%, substantially mitigated moisture loss and decay, presenting an optimal concentration. The coated fruits exhibited a modified total soluble soluble solids, an increased total titratable acidity, and an enhanced sugar-acid ratio, collectively enhancing overall quality. Furthermore, the XG coatings demonstrated the remarkable ability to preserve bioactive compounds, such as total phenolics, flavonoids, and antioxidants, while minimizing the levels of oxidative stress markers, such as electrolyte leakage, malondialdehyde, and H2O2. The coatings also influenced cell wall components, maintaining levels of hemicellulose, cellulose, and protopectin while reducing water-soluble pectin. Quantitative analysis of ROS-scavenging enzymes, including superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase, revealed significant increases in their activities in the XG-coated fruits compared to those in the control fruits. Specifically, on day 15, the 0.75% XG coating demonstrated the highest SOD and CAT activities while minimizing the reduction in APX activity. Moreover, XG coatings mitigated the activities of fruit-softening enzymes, including pectin methylesterase, polygalacturonase, and cellulase. Conclusions This study concludes that XG coatings play a crucial role in preserving postharvest quality of guava fruits by regulating various physiological and biochemical processes. These findings offer valuable insights into the potential application of XG as a natural coating to extend the shelf life and maintain the quality of guava fruits during storage.

This research explored the effects of using Accentuated Cut Edges (ACE) and macerating enzymes on the aroma and sensory profile of Marquette red wines after nine months of aging. The aroma analysis was conducted using gas chromatography-mass spectrometry (GC-MS) with solid-phase microextraction (SPME). The intensity of basic sensory attributes, including color, aroma, taste, and mouthfeel, were evaluated by eight trained panelists through descriptive analysis using 15 cm line scales. ACE treatment affected the aroma compounds profile, as suggested by the increased response ratio of ethyl butanoate, ethyl 2-methylpropanoate, and ethyl 3-methylbutanoate. Statistically, it significantly intensified honey (by 1.6 times) and green apple (by 2.1 times) notes, as perceived by panelists, compared to the control during the sensory descriptive analysis. Regardless of the type of enzymes, combined ACE and enzymes treatment amplified the color intensity of wine by up to 71.4% as observed by panelists, though this was not captured by spectrophotometric measurements (p > 0.05) from the previous study. A lower concentration of ester-derived compounds was found in ACE with enzymes wines, which was associated with the lower intensity of fruity notes during the descriptive analysis. Notably, none of the treatments affected astringency perception, likely due to the low concentration and small molecular weight of condensed tannins, alongside changes in the composition of soluble polysaccharide in Marquette red wines.

Background Guava is a fruit prone to rapid spoilage following harvest, attributed to continuous and swift physicochemical transformations, leading to substantial postharvest losses. This study explored the efficacy of xanthan gum (XG) coatings applied at various concentrations (0.25, 0.5, and 0.75%) on guava fruits (Gola cultivar) over a 15-day storage period. Results The results indicated that XG coatings, particularly at 0.75%, substantially mitigated moisture loss and decay, presenting an optimal concentration. The coated fruits exhibited a modified total soluble soluble solids, an increased total titratable acidity, and an enhanced sugar-acid ratio, collectively enhancing overall quality. Furthermore, the XG coatings demonstrated the remarkable ability to preserve bioactive compounds, such as total phenolics, flavonoids, and antioxidants, while minimizing the levels of oxidative stress markers, such as electrolyte leakage, malondialdehyde, and H2O2. The coatings also influenced cell wall components, maintaining levels of hemicellulose, cellulose, and protopectin while reducing water-soluble pectin. Quantitative analysis of ROS-scavenging enzymes, including superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase, revealed significant increases in their activities in the XG-coated fruits compared to those in the control fruits. Specifically, on day 15, the 0.75% XG coating demonstrated the highest SOD and CAT activities while minimizing the reduction in APX activity. Moreover, XG coatings mitigated the activities of fruit-softening enzymes, including pectin methylesterase, polygalacturonase, and cellulase. Conclusions This study concludes that XG coatings play a crucial role in preserving postharvest quality of guava fruits by regulating various physiological and biochemical processes. These findings offer valuable insights into the potential application of XG as a natural coating to extend the shelf life and maintain the quality of guava fruits during storage. [ABSTRACT FROM AUTHOR]

This review focuses on the pivotal role microscopy has played in diagnosing the type(s) of microbial attacks present in waterlogged ancient wooden objects, and to understand the nature and extent of deterioration of such objects. The microscopic journey began with the application of light microscopy (LM) to examine the deterioration of waterlogged woods, notably foundation piles supporting historic buildings, progressing into the use of high-resolution imaging tools (SEM and TEM) and techniques. Although bacteria were implicated in the deterioration of foundation piles, confirmation that bacteria can indeed degrade wood in its native state came when decaying wood from natural environments was examined using electron microscopy, particularly TEM, which enabled bacterial association with cell wall regions undergoing degradation to be clearly resolved. The information base has been a catalyst, stimulating numerous studies in the past three decades or so to understand the nature of microbial degradation of waterlogged archaeological wood more precisely, combining LM, SEM, and TEM with high-resolution chemical analytical methods, including chemical microscopy. The emerging information is aiding targeted developments towards a more effective conservation of ancient wooden objects as they begin to be uncovered from burial and waterlogging environments. [ABSTRACT FROM AUTHOR]

Peaches are subject to flesh softening during postharvest storage and transport, which affects the storage life of the fruit and causes huge economic losses. Previous research has demonstrated that postharvest brassinolide treatment can maintain flesh firmness, ascorbic acid and soluble solids contents, and enhance disease resistance in peach fruits. This study assessed the influence of postharvest brassinolide treatment on the expression of key genes involved in cell wall degradation and the phenylpropanoid pathway in peach fruits by real-time fluorescence quantitative polymerase chain reaction (qPCR). The results showed that brassinolide dipping inhibited the gene expression of pectate lyase 1, polygalacturonase 21 and pectin methylesterase 1, and significantly enhanced the gene expression of peroxidase, cinnamoyl-CoA reductase, phenylalanine ammonia lyase and caffeoyl-CoA-O-methyltransferase 5 in peach fruits. It also increased the gene expression levels of chaleone synthase, chaleone isomerase, dihydroflavonol-4-reductase and flavanone 3-hydroxylase at the early stage of storage. These findings imply that brassinolide can suppress the expression of key genes involved in cell wall degradation and enhance the expression of key genes involved in the phenylpropanoid pathway, thereby delaying peach fruit softening and enhancing disease resistance.

Abstract Background Microspore embryogenesis is an extraordinarily complicated process, comprehensively regulated by a composite network of physiological and molecular factors, among which hormone is one of the most crucial factors. Auxin is required for stress-induced microspore reprogramming, however, the mechanism of its regulation of microspore embryogenesis is still unclear. Results In this study, we found exogenously spraying 100 mg·L− 1 IAA on the buds of Wucai significantly increased the rate of microspore embryogenesis, and moreover accelerated the process of embryogenesis. Physiological and biochemical tests showed that the contents of amino acids, soluble total sugar, soluble protein, and starch were significantly increased after IAA treatment. Furthermore, exogenously spraying 100 mg·L− 1 IAA significantly enhanced IAA, GA4, and GA9 content, increased catalase (CAT) and malondialdehyde (MDA) activity, and reduced abscisic acid (ABA), MDA and soluble protopectin content, H2O2 and O2· − production rate in the bud with the largest population of late-uninucleate-stage microspores. Transcriptome sequencing was performed on buds respectively treated with 100 mg·L− 1 IAA and fresh water. A total of 2004 DEGs were identified, of which 79 were involved in micropores development, embryonic development and cell wall formation and modification, most of which were upregulated. KEGG and GO analysis revealed that 9.52% of DEGs were enriched in plant hormone synthesis and signal transduction pathways, pentose and glucuronic acid exchange pathways, and oxidative phosphorylation pathways. Conclusions These findings indicated that exogenous IAA altered the contents of endogenous hormone content, total soluble sugar, amino acid, starch, soluble protein, MDA and protopectin, the activities of CAT and peroxidase (POD), and the production rate of H2O2 and O2· − . Combined with transcriptome analysis, it was found that most genes related to gibberellin (GA) and Auxin (IAA) synthesis and signal transduction, pectin methylase (PME) and polygalacturonase (PGs) genes and genes related to ATP synthesis and electron transport chain were upregulated, and genes related to ABA synthesis and signal transduction were downregulated. These results indicated that exogenous IAA treatment could change the balance of endogenous hormones, accelerate cell wall degradation, promote ATP synthesis and nutrient accumulation, inhibit ROS accumulation, which ultimately promote microspore embryogenesis.

Green tea residue (GTR) contains a high protein content. However, the protein in GTR can't be effectively extracted using traditional methods. Thus, a novel method using ethylenediamine tetraacetic acid (EDTA), ammonium oxalate, or Celluclast® 1.5 L were used to disperse leaf tissues and to collect mesophyll cells to enrich the protein. Compared with EDTA or ammonium oxalate treatment, Celluclast® 1.5 L treatment achieved the highest amounts of mesophyll cells, about 2.7 × 106 g−1 of GTR. The number of collected mesophyll cells was positively and linearly correlated with the extraction rate of glucose and xylose, indicating that cellulose and hemicellulose were key components influencing cell collection. Celluclast® 1.5 L treatment enriched the protein content by 1.65 times in collected mesophyll cells to 50% protein content with a protein recovery of 88%, providing a novel scheme to obtain high-quality leaf protein for the food industry.

In this study, spruce wood was modified by ring-opening polymerization of ε-caprolactone to graft poly (ε-caprolactone) into wood cell wall by impregnation of 30%, 50%, and 70% monomer concentrations and further polymerization in DMF solution. The biodegradability of the modified wood by the wood-decaying fungi was investigated by means of weight losses, and the chemical and morphological background of the degradation process was analyzed through FTIR and SEM analysis, respectively. For this purpose, modified samples were exposed to brown rot fungi Coniophora puteana and Postia placenta, and white rot fungi Trametes versicolor and Pleurotus ostreatus attacks to determine the optimum concentration level of ε-caprolactone monomer for sufficient decay resistance on media inoculated with malt-extract agar and soil, according to principles of CEN EN 113 and ASTM D 1413, respectively. A leaching test was conducted in order to evaluate any loss in effectiveness in decay resistance. Results showed that all concentrations of PCL exhibited superior decay resistance in samples after the decay test was conducted on agar media. However, modified samples gave high weight losses in soil contact decay testing. P. placenta and P. ostreatus attacks were found to be more aggressive in modified samples than other fungi attacks. 70% ε-caprolactone concentration was found more efficacious in suppressing brown rot fungi attacks than lower concentrations, whilst lower concentration levels were found to be more efficacious in suppressing white rot fungi attacks than 70% concentration level. SEM and FTIR findings proved that weight losses were due to both cell wall degradations and polymer digestion by fungal enzymes. SEM study revealed that cell wall modification inhibits the consumption of cell wall polymers compared to controls. [ABSTRACT FROM AUTHOR]

Background: Microspore embryogenesis is an extraordinarily complicated process, comprehensively regulated by a composite network of physiological and molecular factors, among which hormone is one of the most crucial factors. Auxin is required for stress-induced microspore reprogramming, however, the mechanism of its regulation of microspore embryogenesis is still unclear. Results: In this study, we found exogenously spraying 100 mg·L− 1 IAA on the buds of Wucai significantly increased the rate of microspore embryogenesis, and moreover accelerated the process of embryogenesis. Physiological and biochemical tests showed that the contents of amino acids, soluble total sugar, soluble protein, and starch were significantly increased after IAA treatment. Furthermore, exogenously spraying 100 mg·L− 1 IAA significantly enhanced IAA, GA4, and GA9 content, increased catalase (CAT) and malondialdehyde (MDA) activity, and reduced abscisic acid (ABA), MDA and soluble protopectin content, H2O2 and O2·− production rate in the bud with the largest population of late-uninucleate-stage microspores. Transcriptome sequencing was performed on buds respectively treated with 100 mg·L− 1 IAA and fresh water. A total of 2004 DEGs were identified, of which 79 were involved in micropores development, embryonic development and cell wall formation and modification, most of which were upregulated. KEGG and GO analysis revealed that 9.52% of DEGs were enriched in plant hormone synthesis and signal transduction pathways, pentose and glucuronic acid exchange pathways, and oxidative phosphorylation pathways. Conclusions: These findings indicated that exogenous IAA altered the contents of endogenous hormone content, total soluble sugar, amino acid, starch, soluble protein, MDA and protopectin, the activities of CAT and peroxidase (POD), and the production rate of H2O2 and O2·−. Combined with transcriptome analysis, it was found that most genes related to gibberellin (GA) and Auxin (IAA) synthesis and signal transduction, pectin methylase (PME) and polygalacturonase (PGs) genes and genes related to ATP synthesis and electron transport chain were upregulated, and genes related to ABA synthesis and signal transduction were downregulated. These results indicated that exogenous IAA treatment could change the balance of endogenous hormones, accelerate cell wall degradation, promote ATP synthesis and nutrient accumulation, inhibit ROS accumulation, which ultimately promote microspore embryogenesis. [ABSTRACT FROM AUTHOR]

Fresh Hericium erinaceus is susceptible to softening after harvest, 1.0 kGy electron-beam generated X-ray (EBGX) irradiation could alleviate this phenomenon. To clarify the possible mechanism of EBGX regulated the softening of H. erinaceus , we explored its effects on membrane lipid and cell wall metabolism. Results showed that 1.0 kGy irradiation enhanced cell membrane stability, as evidenced by higher levels of phosphatidic acid, phosphatidylcholine, phosphatidylinositol, and the ratio of unsaturated fatty acids to saturated fatty acids (U/S), whereas lower levels of ROS, lipoxygenase, phospholipase D, and lipase activities compared to the control. More importantly, 1.0 kGy-treated samples exhibited a minimum of chitinase (4.12 U mg−1), cellulase (16.34 U mg−1), β-glucanase (13.28 U mg−1), and PAL (10.17 U mg−1) activities at 9d, but retained higher chitin, cellulose, β-glucan, and lignin contents, thus suppressed the disassembly of cell wall structure. Utilizing comparative transcriptomic data, the differentially expressed genes (DEGs) from starch and sucrose metabolism, amino sugar and nucleotide sugar metabolism, and lipid degradation metabolism were related to softening in H. erinaceus with control or irradiation treatments. Additionally, the relative abundance of DEGs-related transcripts like HeLOX , HePLD , HeLPS , HeCHI , HeCEL , HeGLU1 , HeGLU2 , and HePAL were prominently downregulated in the irradiation treatment. Overall, 1.0 kGy EBGX irradiation could retard the postharvest softening process of H. erinaceus by regulating the gene expression of membrane lipids and cell wall metabolic pathways. [Display omitted] • kGy-treated H. erinaceus maintained membrane metabolic homeostasis to resist lipid oxidation. • kGy treatment retained higher cell wall components in H. erinaceus. • kGy treatment reduced the peak activity of cell wall metabolic enzymes during storage. • EBGX irradiation delayed cell wall degradation via regulating softening related pathway. • EBGX irradiation downregulated the transcription levels of genes involved in softening. [ABSTRACT FROM AUTHOR]

Asparagus is prone to weight loss and aging after harvest. 2,4-Epibrassinolide (EBR), a brassinosteroid hormone, is widely involved in plant growth, development, and stress response. This study investigated the effects of different EBR treatments (0, 2.5, 5, 7.5, 10, and 15 μmol L−1) on the sensory quality and biochemical substance content of asparagus stored at 4°C for 5, 10, 15, 20, and 25 d. The results showed that EBR application effectively mitigates weight loss and quality deterioration during storage. This effect was evidenced by higher firmness, total chlorophyll content, soluble protein, total saponins, mechanical tissue thickness, and lower lignin content and malondialdehyde levels. Moreover, EBR enhances the antioxidant capacity of asparagus by regulating the enzymatic antioxidant system (superoxide dismutase, catalase, peroxidase, and polyphenol oxidase activities) and the non-enzymatic antioxidant system (DPPH free radical scavenging ability, vitamin C, total phenol, total flavonoids, rutin, amino acids, and proline content), thus, reducing oxidative damage. Furthermore, transcriptome analysis revealed that the softening and aging of asparagus are closely related to phenylpropanoid biosynthesis and starch and sucrose metabolism. 2,4-Epibrassinolide inhibits lignification by reducing the expression of lignin synthesis-related genes (PAL , C4H , 4CL , COMT , CCR , CAD , and POD). Additionally, EBR delays asparagus softening by suppressing cell wall degradation-related genes (Egase , β-BGL , PE , and PG). Weighted Gene Co-expression Network Analysis (WGCNA) identified 12 lignification-related candidate genes and five softening-related candidate genes. Additionally, the RT-qPCR expression of the 17 candidate genes was consistent with the transcriptome results. Altogether, this study provides a basis for EBR application in asparagus storage and preservation and offers insights into the molecular mechanisms by which EBR delays lignification and softening in asparagus. • EBR can inhibit the softening and lignification in asparagus during storage. • EBR treatment can delay the loss of greenness and firmness reduction in asparagus during storage. • EBR treatment can increase the antioxidant capacity of asparagus. • EBR treatment (7.5 μmol L −1) is most effective in delaying lignification and softening of asparagus. [ABSTRACT FROM AUTHOR]

Synaptotagmins (SYTs), initially identified as calcium sensors for regulating synaptic vesicle exocytosis and endocytosis in mammalian neurons, play crucial role in biotic and abiotic stresses in plants. However, the function of SYTs in fruit ripening is unclear. In this study, a tomato Synaptotagmins gene, SlSYTF , was found to accelerate tomato fruit ripening. SlSYTF encodes an endoplasmic reticulum localized protein whose transcription is continuously enhanced during fruit ripening. Overexpression SlSYTF in tomato resulted in accelerated ripening progress, increased carotenoid content as well as decreased the firmness of tomato fruit, whereas the mutant slsytf-c exhibited the opposite phenotype. Importantly, SlSYTF could increase ethylene production by activating the expression of ethylene synthesis genes and prompt cell wall degradation by increasing pectinase and cellulase activities. Nevertheless, the accelerated cell wall degradation and thinned cuticle due to SlSYTF results in reduced shelf life and pathogen resistance. Collectively, we revealed a new SYTs gene that plays a dual role in tomato fruit ripening and pathogen response. This finding may shed new light on the relationship between maturation and immunity. • A Synaptotagmins gene SlSYTF was found to accelerate tomato fruit ripening. • SlSYTF activates transcription of ethylene synthesis genes to increase the production. • SlSYTF prompts cell wall degradation by increasing pectinase and cellulase activities. • SlSYTF reduces fruits shelf life and disease resistance. [ABSTRACT FROM AUTHOR]

Green macroalgae, e.g., Ulva lactuca, are valuable bioactive sources of nutrients; but algae recalcitrant cell walls, composed of a complex cross-linked matrix of polysaccharides, can compromise their utilization as feedstuffs for monogastric animals. This study aimed to evaluate the ability of pre-selected Carbohydrate-Active enZymes (CAZymes) and sulfatases to degrade U. lactuca cell walls and release nutritive compounds. A databank of 199 recombinant CAZymes and sulfatases was tested in vitro for their action towards U. lactuca cell wall polysaccharides. The enzymes were incubated with the macroalga, either alone or in combination, to release reducing sugars and decrease fluorescence intensity of Calcofluor White stained cell walls. The individual action of a polysaccharide lyase family 25 (PL25), an ulvan lyase, was shown to be the most efficient in cell wall disruption. The ulvan lyase treatment, in triplicate measures, promoted the release of 4.54 g/L (P 0.05), proteins (P = 0.861) or pigments (P > 0.05) was found. These results highlight the capacity of a single recombinant ulvan lyase (PL25 family) to incompletely disrupt U. lactuca cell walls. This enzyme could enhance the bioaccessibility of U. lactuca bioactive products with promising utilization in the feed industry.

Heat stress in summer causes softening disorder in papaya but the molecular mechanism is not clear. In this study, papaya fruit stored at 35 °C showed a softening disorder termed rubbery texture. Analysis of the transcriptome and metabolome identified numerous differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) between the fruit stored at 25 °C and 35 °C. The DEGs and DAMs related to lignin biosynthesis were upregulated, while those related to ethylene biosynthesis, sucrose metabolism, and cell wall degradation were downregulated under heat stress. Co-expression network analysis highlighted the correlation between the DEGs and metabolites associated with lignin biosynthesis, ethylene biosynthesis, and cell wall degradation under heat stress. Finally, the correlation analysis identified the key factors regulating softening disorder under heat stress. The study's findings reveal that heat stress inhibited papaya cell wall degradation and ethylene production, delaying fruit ripening and softening and ultimately resulting in a rubbery texture. [Display omitted] • Heat stress inhibit the ethylene production and delayed the fruit ripening. • Heat stress reduced the enzymes activities related to cell wall (CW) degradation. • Heat stress induced large number of DEGs in cell wall degradation related pathways. • Heat stress induced lignification and inhibit CW degradation, leads to rubbery texture. • Heat stress inhibited the metabolites related to CW degradation. [ABSTRACT FROM AUTHOR]

Wood colonizing fungi are specialists that exploit the lignocellulose of cell wall components in host wood cylinders as a carbon sources. Some of these specialized fungi, including Fomitiporia mediterranea (Fmed) and Phaeomoniella chlamydospora (Pch), cause the disease Esca of grapevine. This disease complex includes grapevine leaf stripe disease (GLSD) of canopies and white rot and black wood streaking in trunks. The present study gained insights into the activity of Esca pathogens in host xylem of the trunk tissues at an anatomical level. Lesions with white rot and brown wood streaking were microscopically analyzed, and the structures of affected tissues were compared with intact xylem. In trunks with white rot, demarcation zones separated intact tissues from the lesions. Immediately adjacent to the demarcation zones, cell wall decomposition initiated in the xylem. At this initial stage, cavities appeared in the secondary cell walls of libriform fibres, which expanded and closely resembled the degradation pattern of soft rot. In the advanced stage, the fibre cell walls were completely decomposed, and the vessels were attacked with a degradation pattern similar to white rot. Only remnants of the xylem elements remained, forming amorphous matrices. These decomposition patterns occurred in field samples and in wood cores artificially infected with Fmed. The obvious compartmentalization of the tissue affected by Fmed indicated a defense reaction in the xylem, according to the CODIT model. In contrast, brown wood streaking affected only small groups of vessels, adjacent libriform fibres and parenchyma. Dark inclusions in cells and tyloses in vessels indicate a defense reaction against the pathogens causing brown wood streaking. Artificial inoculation of sterile wood cores with Pch confirmed the contribution of this pathogen to brown wood streaking. This research provides insights into the structural and functional anatomy of intact and infected tissues of grapevines, which clarify the etiology of Esca, and provide new knowledge for developing new approaches to control of this disease complex. [ABSTRACT FROM AUTHOR]

Puccinia striiformis f. sp. tritici ( Pst ) secretes a plethora of cell wall-degrading enzymes (CWDEs) to facilitate fungal invasion during infection. However, the functions and molecular mechanisms of the CWDEs from Pst remain unclear. In this study, we identified a secreted xylanase, named PstXyn1, with the GH10 domain. PstXyn1 was significantly up-regulated at the early infection stage of Pst. The signal peptide of PstXyn1 was confirmed to be functional. The purified PstXyn1 showed detectable xylanase activity. In addition, we found that PstXyn1 -silenced wheat plants exhibited broad-spectrum resistance against multiple Pst pathotypes. Colloidal gold labeling and transcriptome sequencing analyses revealed that PstXyn1 contributed to xylan degradation in host cell walls and suppressed the expression of defense-related genes. Conclusively, our results indicate that PstXyn1 is secreted as an important virulence factor to overcome host cell wall barriers and compromise immune responses for fungal invasion, providing potential targets for improving wheat resistance to stripe rust.

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The ascomycete Neofusicoccum parvum, one of the causal agents of Botryosphaeria dieback, is a destructive wood-infecting fungus and a serious threat to grape production worldwide. The capability to colonize woody tissue, combined with the secretion of phytotoxic compounds, is thought to underlie its pathogenicity and virulence. Here, we describe the repertoire of virulence factors and their transcriptional dynamics as the fungus feeds on different substrates and colonizes the woody stem. We assembled and annotated a highly contiguous genome using single-molecule real-time DNA sequencing. Transcriptome profiling by RNA sequencing determined the genome-wide patterns of expression of virulence factors both in vitro (potato dextrose agar or medium amended with grape wood as substrate) and in planta. Pairwise statistical testing of differential expression, followed by co-expression network analysis, revealed that physically clustered genes coding for putative virulence functions were induced depending on the substrate or stage of plant infection. Co-expressed gene clusters were significantly enriched not only in genes associated with secondary metabolism, but also in those associated with cell wall degradation, suggesting that dynamic co-regulation of transcriptional networks contributes to multiple aspects of N. parvum virulence. In most of the co-expressed clusters, all genes shared at least a common motif in their promoter region, indicative of co-regulation by the same transcription factor. Co-expression analysis also identified chromatin regulators with correlated expression with inducible clusters of virulence factors, suggesting a complex, multi-layered regulation of the virulence repertoire of N. parvum.

Rapid softening is one of the major concerns for the postharvest storage of kiwiberry (Actinidia arguta), which leds to quality deterioration and reduced commercial value. Understanding the mechanisms of kiwiberry ripening and softening at the molecular level becomes urgent as it could help to create kiwiberry varieties with favorable storage properties. This study analyzed the postharvest ripening process of kiwiberry and revealed that solubilization of pectin and depolymerization of hemicellulose mainly contributed to fruit softening. Based on the RNA-seq data and weighted gene co-expression network analysis (WGCNA), four cell wall degradation-related genes AaPG1 , AaXTH28 and AaPME1 / 2 were revealed. Moreover, a bHLH transcription factor AaBIM1, which functioned as a transcriptional repressor of cell wall degradation-related genes was identified via dual-luciferase assay and yeast one-hybrid, and its expression profile showed a downward trend during postharvest ripening. Transient overexpression of AaBIM1 in kiwiberry core tissue delayed fruit softening and decreased the expression of downstream structural genes. These findings supported the critical role of AaBIM1 in regulating cell wall metabolism and provided insights into understanding kiwiberry softening for further improvement by breeding. [Display omitted] • Rapid softening poses a major challenge in preserving kiwiberry (Actinidia arguta). • Degradation of pectin and hemicellulose mainly contributed to kiwiberry softening. • Four cell wall degradation-related genes were involved in cell wall metabolism. • AaBIM1 plays a role in regulating cell wall degradation and kiwiberry softening. [ABSTRACT FROM AUTHOR]

[Display omitted] • Accentuated Cut Edges (ACE) and enzymes applied simultaneously to 'Marquette' grapes. • ACE promoted phenolic compounds diffusion at crushing. • Macerating enzyme had less pronounced effect on phenolic extraction compared to ACE. • Cold-hardy interspecific grape cultivars may require intensive skin degradation. One of the challenges of cold-hardy grape cultivars is their typical low content of tannins, alongside the presence of anthocyanin diglucoside and high acidity, which can lead to unbalanced red wines. This study hypothesized that the combination of Accentuated Cut Edges (ACE) and macerating enzymes would improve phenolics extraction from grape skins after disruption. The effects of those two winemaking techniques, either used separately or together, on red wine quality characteristics were investigated at crushing, bottling, and after six or nine months of aging. Overall, the combination of treatments improved the concentration of monomeric phenolics (20 %) and tannins (21 %) after nine months of aging. ACE or enzyme treatment separately applied had little impact on phenolics extraction in finished wines. This study exhibited a potential strategy to modify phenolics profile through the synergistic effect of ACE and macerating enzymes by causing cellular breakdown in a cold-hardy red grape cultivar. [ABSTRACT FROM AUTHOR]

Drought significantly impacts cotton square (flower buds with bracts) shedding, directly affecting yield. To address the internal physiological mechanisms of drought affecting cotton square shedding, a polyethylene glycol-simulated drought study was conducted with Dexiamian 1 and Yuzaomian 9110 to investigate cell wall degradation changes in the base of pedicel where the detachment of cotton square takes place, and its relationship with cotton square shedding. Results revealed significant decreases in cellulose, hemicellulose, and pectin contents in the base of square pedicel, leading to cell wall degradation and consequent square shedding. Furthermore, drought stress exacerbated the hydrolysis of cellulose and pectin in the base of pedicel, although not hemicellulose, resulting in more noticeable alterations in the morphology and structure of the base of pedicel, such as more significant degradation in the epidermis, cortex, and phloem. Regarding the cellulose hydrolysis, drought mainly increased the expression of genes β-glucosidase (GhBG1) and endoglucanase (GhEG1), and the activity of β-glucosidase and endoglucanase in the base of pedicel, promoting the conversion of cellulose to cellobiose, and eventually glucose. Regarding the pectin hydrolysis, drought significantly enhanced the expression of the gene pectin methylase (GhPE1), thereby accelerating pectin hydrolysis to generate polygalacturonic acid. Additionally, drought increased the expression of genes pectin lyase (GhPL1) and polygalacturonase (GhPG1), as well as the activity of pectin lyase, which further accelerated the hydrolysis of polygalacturonic acid into galacturonic acid. These findings suggest that drought mainly promotes cellulose and pectin hydrolysis in the base of pedicel, hastening cell wall degradation and final cotton square shedding. • Cell wall degradation in the base of pedicel leads to square shedding. • Drought boosts cell wall degradation in the base of pedicel. • Drought accelerates the hydrolysis of cellulose and pectin, not hemicellulose. [ABSTRACT FROM AUTHOR]

Low R/FR irradiation can promote dodder haustorium formation on the host plant; however, the mechanisms underlying the process are still unknown. In this study, we compared the transcriptomic data during the formation of haustorium of Cuscuta chinensis on host plant Arabidopsisthaliana under low (R/FR = 0.1) versus high (R/FR = 0.2) R/FR irradiation at 12 h, 24 h and 72 h time points. The results show that low R/FR radiation significantly promoted the entanglement and haustorium formation. Transcriptome analysis showed that during the early stage of haustorium formation, low R/FR radiation significantly up-regulated ARR-A related genes and down-regulated peroxidase related genes compared with high R/FR radiation. Meanwhile, during the middle stage of haustorium formation, low R/FR treatment significantly increased the expression of genes related to pectinesterase (PE), polygalacturonase (PG) and pectin lyase (Pel) production, while, during the late stage of haustorium formation, peroxidase (Prx)-related genes were differentially expressed under different R/FR treatments. Overall, our findings show that a low R/FR ratio promotes the parasitism of C. chinensis through plant hormone signal transduction and cell wall degradation pathways. This study provides a basis for the control of parasitic plants. [ABSTRACT FROM AUTHOR]

This review provides information on the advances made leading to an understanding of the micromorphological patterns produced during microbial degradation of lignified cell walls of buried and waterlogged archaeological woods. This knowledge not only serves as an important diagnostic signature for identifying the type(s) of microbial attacks present in such woods but also aids in the development of targeted methods for more effective preservation/restoration of wooden objects of historical and cultural importance. In this review, an outline of the chemical and ultrastructural characteristics of wood cell walls is first presented, which serves as a base for understanding the relationship of these characteristics to microbial degradation of lignocellulosic cell walls. The micromorphological patterns of the three different types of microbial attacks—soft rot, bacterial tunnelling and bacterial erosion—reported to be present in waterlogged woods are described. Then, the relevance of understanding microbial decay patterns to the preservation of waterlogged archaeological wooden artifacts is discussed, with a final section proposing research areas for future exploration. [ABSTRACT FROM AUTHOR]

Plant cell wall acts as a primary barrier for microbial pathogens during infection. A cell wall-degrading enzyme thus may be a crucial virulence factor, as it may aid the pathogen in successful host invasion. Nine genes coding for feruloyl esterases (Fae), likely involved in plant cell wall degradation, have been annotated in the genome of the cereal-blast fungus Magnaporthe oryzae. However, role of any Fae in pathogenicity of M. oryzae remains hitherto under explored. Here, we identified FAE1 gene (MGG_08737) that was significantly upregulated during host penetration and subsequent colonisation stages of infection. Accordingly, while deletion of FAE1 in M. oryzae did not affect the vegetative growth and asexual development, the fae1Δ mutant showed significantly reduced pathogenesis on rice plants, mainly due to impaired host invasion and colonisation. Very few (< 10%) fae1Δ appressoria that formed the primary invasive hyphae failed to elaborate from the first invaded cell to the neighbouring plant cells. Interestingly, exogenously added glucose, as a simple carbon source, or ferulic acid, a product of the Fae activity, significantly supported the invasive growth of the fae1Δ mutant. We show that the Fae1-based feruloyl esterase activity, by targeting the plant cell wall, plays an important role in accumulating ferulic acid and/or sugar molecules, as a likely energy source, to enable host invasion and colonisation by M. oryzae. Given its role in plant cell wall digestion and host colonisation, M. oryzae Fae1 could be a potential candidate for a novel antifungal strategy and a biotechnological application in biofuel production. [ABSTRACT FROM AUTHOR]

Flesh softening is closely related to the quality of postharvest produces. Although the use of calcium chloride (CaCl 2) has been shown to inhibit fruit softening, the underlying molecular mechanisms have remained unclear. In our present investigation, CaCl 2 treatment resulted in an enhancement of cytosolic free Ca2+ and polysaccharide contents, firmness, and the integrity of the cell wall structure, particularly evident in the denser middle lamella of fresh-cut cantaloupe. CaCl 2 treatment also inhibited the cell wall degrading enzyme activities and gene expressions. Moreover, CmCAMTA2 could identify and bind to the CG-box structure of CmCellulase , Cmα-Gal3 , and Cmβ-Glu12 , thereby suppressing their transcription. In conclusion, current findings illustrated that CaCl 2 treatment triggered CmCAMTA2-mediated transcriptional suppression on cell wall degrading genes, inhibited the polysaccharide component degradation, and maintained better structure integrity of the cell wall, thereby delaying the flesh softening of fresh-cut cantaloupe. • CaCl 2 application delayed flesh softening of fresh-cut cantaloupe. • CaCl 2 maintained the structure integrity of cell wall in fresh-cut cantaloupe. • CaCl 2 lessened the polysaccharide component degradation of fresh-cut cantaloupe. • CaCl 2 treatment stimulated Ca2+ accumulation and the expression of CmCAMTA2. • Cell wall degradation was negatively modulated by Ca2+-CAMTA2 signal pathway. [ABSTRACT FROM AUTHOR]

Melatonin plays an important role in maintaining the postharvest quality of fresh fruit. This study focused on the effect of exogenous melatonin on fruit softening and ROS metabolism in green pepper fruit under storage at 20℃. Our results indicated that melatonin treatment reduced the transcript levels of genes encoding polygalacturonase, β-glucanase (associated with hydrolysis of cell wall components), lipoxygenase and phospholipase enzymes, associated with membrane stability, thereby preserving the firmness of harvested green pepper fruits; the decreased transcription of the phospholipase gene was associated with melatonin-induced downregulation of expression of a corresponding transcription factor gene. In addition, melatonin treatment induced the transcription of genes encoding the antioxidant enzymes catalase and peroxidase, upregulated the activities of the same enzymatic antioxidants and increased the ratios of glutathione-to-glutathione disulfide and of ascorbic acid to dehydroascorbic acid. As a consequence, the concentrations of intracellular superoxide anions, H 2 O 2 and malondialdehyde were decreased, reducing the accumulation of reactive oxygen species and the lipid peroxidation of cell membranes. In summary, this work proved that exogenous melatonin application delays the softening of pepper fruits postharvest and hence extends their storage period and shelf life. • Melatonin treatment preserves firmness of green pepper fruits (Capsicum annuum L.). • Melatonin treatment reduces CaPG , CaEG , CaPLDα4 and CaLOX genes transcript levels. • Melatonin treatment reduces the concentrations of intracellular O2-, H 2 O 2 and MDA. • Melatonin treatment increases CAT and POD activities, GSH/GSSG and AsA/DHA ratio. [ABSTRACT FROM AUTHOR]

BACKGROUND Monascus fermentation byproduct (MFB) is a biowaste generated after food colorants are extracted. Using MFB to produce probiotics (Bacillus subtilis) is a sustainable way for the entire production to be used as food or animal feed additives. However, due to the rigidity of the Monascus mycelium cell wall, B. subtilis cannot sufficiently utilize the nutrients in MFB, leading to low biomass production efficiency. We studied the effects of ultrasonic treatment, papain, β‐glucanase, and chitosanase, and their combinations on improving the levels of soluble components from MFB. The effects of these treatments on mycelium cell walls were visualized using scanning electron microscopy, and their influence on B. subtilis production was analyzed. RESULTS: Ultrasonic treatment increased the soluble components by 210 g kg−1, including 50 g kg−1 protein and 120 g kg−1 carbohydrates. An enzyme mixture increased the soluble components by 160 g kg−1, including 30 g kg−1 protein and 90 g kg−1 carbohydrates. The combination of the two methods achieved the highest increase of soluble components (up to 400 g kg−1) leading to a maximum B. subtilis production of 1 × 1011 colony‐forming unit mL−1. This yield was about 20 times greater than that using untreated MFB and about eight times greater than treatments using only ultrasonic or enzymatic methods. CONCLUSION: The productivity of B. subtilis production using MFB as the sole medium can be greatly improved by ultrasound or enzymes, which cause the release of intercellular components or cell wall components. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background Lentinula edodes is one of the most popular edible mushroom species in the world and contains useful medicinal components, such as lentinan. The light-induced formation of brown film on the vegetative mycelial tissues of L. edodes is an important process for ensuring the quantity and quality of this edible mushroom. To understand the molecular mechanisms underlying this critical developmental process in L. edodes, we characterized the morphological phenotypic changes in a strain, Chamaram, associated with abnormal brown film formation and compared its genome-wide transcriptional features. Results In the present study, we performed genome-wide transcriptome analyses of different vegetative mycelium growth phenotypes, namely, early white, normal brown, and defective dark yellow partial brown films phenotypes which were exposed to different light conditions. The analysis revealed the identification of clusters of genes specific to the light-induced brown film phenotypes. These genes were significantly associated with light sensing via photoreceptors such as FMN- and FAD-bindings, signal transduction by kinases and GPCRs, melanogenesis via activation of tyrosinases, and cell wall degradation by glucanases, chitinases, and laccases, which suggests these processes are involved in the formation of mycelial browning in L. edodes. Interestingly, hydrophobin genes such as SC1 and SC3 exhibited divergent expression levels in the normal and abnormal brown mycelial films, indicating the ability of these genes to act in fruiting body initiation and formation of dikaryotic mycelia. Furthermore, we identified the up-regulation of glycoside hydrolase domain-containing genes in the normal brown film but not in the abnormal film phenotype, suggesting that cell wall degradation in the normal brown film phenotype is crucial in the developmental processes related to the initiation and formation of fruiting bodies. Conclusions This study systematically analysed the expression patterns of light-induced browning-related genes in L. edodes. Our findings provide information for further investigations of browning formation mechanisms in L. edodes and a foundation for future L. edodes breeding.

The human pathogen Pseudomonas aeruginosa harbors three paralogous zinc proteases annotated as AmpD, AmpDh2, and AmpDh3, which turn over the cell wall and cell wall‐derived muropeptides. AmpD is cytoplasmic and plays a role in the recycling of cell wall muropeptides, with a link to antibiotic resistance. AmpDh2 is a periplasmic soluble enzyme with the former anchored to the inner leaflet of the outer membrane. We document, herein, that the type VI secretion system locus II (H2‐T6SS) of P. aeruginosa delivers AmpDh3 (but not AmpD or AmpDh2) to the periplasm of a prey bacterium upon contact. AmpDh3 hydrolyzes the cell wall peptidoglycan of the prey bacterium, which leads to its killing, thereby providing a growth advantage for P. aeruginosa in bacterial competition. We also document that the periplasmic protein PA0808, heretofore of unknown function, affords self‐protection from lysis by AmpDh3. Cognates of the AmpDh3‐PA0808 pair are widely distributed across Gram‐negative bacteria. Taken together, these findings underscore the importance of their function as an evolutionary advantage and that of the H2‐T6SS as the means for the manifestation of the effect. [ABSTRACT FROM AUTHOR]

Recycling biomass is indispensable these days not only because fossil energy sources are gradually depleted, but also because pollution of the environment, caused by the increasing use of energy, must be reduced. This article intends to overview the results of plant biomass processing methods that are currently in use. Our aim was also to review published methods that are not currently in use. It is intended to explore the possibilities of new methods and enzymes to be used in biomass recycling. The results of this overview are perplexing in almost every area. Advances have been made in the pre-treatment of biomass and in the diversity and applications of the enzymes utilized. Based on molecular modeling, very little progress has been made in the modification of existing enzymes for altered function and adaptation for the environmental conditions during the processing of biomass. There are hardly any publications in which molecular modeling techniques are used to improve enzyme function and to adapt enzymes to various environmental conditions. Our view is that using modern computational, biochemical, and biotechnological methods would enable the purposeful design of enzymes that are more efficient and suitable for biomass processing. [ABSTRACT FROM AUTHOR]

Breaking cell wall is a key step for extracting intracellular components such as proteins and lipids from microalgae. This study investigated an alternative way to disrupt microalgae cell structure by controlling pH during anaerobic digestion. The undigested lipid fractions from microalgae was preserved as long chain fatty acids (LCFAs) through pH control at alkaline condition. The optimum anaerobic hydrolysis was observed under alkaline condition at pHs 10 and 11; a maximum concentration of LCFAs (1150 mg/L) was observed at pH 11.0 on the fourth day of anaerobic digestion, which mainly consisted of palmitic acid and palmitoleic acid. Under alkaline condition, no methane was produced because of the inhibition of methanogenesis. However, the efficiency of organics hydrolysis was significantly enhanced as more soluble chemical oxygen demand (SCOD) was detected at pH 10 (11,170 mg/L SCOD) and pH 11 (12,273 mg/L SCOD), which was nearly twice higher than neutral pH. Also, confocal and transmission electron microscopy images illustrated the damage of microalgae cell wall and distribution of released LCFAs. The results provide insight for developing low-cost options for harvesting lipids from algal biomass. • The effects of pH on hydrolase activity during anaerobic digestion was studied. • The highest concentration and yield of LCFAs were at pH 11. • The highest concentration and yield of VFAs and biogas were at pH 7. • The degradation of microalgae cell wall was verified at TEM. [ABSTRACT FROM AUTHOR]

BACKGROUND Hydrogen sulfide (H2S) is a known signaling molecule in plants, which has the ability to delay fruit ripening. Our previous studies have shown that H2S treatment could delay the maturation of kiwifruits by inhibiting ethylene production, improving protective enzyme activities, and decreasing the accumulation of reactive oxygen species to protect the cell membrane during storage. The mechanism related to the way in which H2S affected kiwifruit maturation was still unclear. We performed transcriptome sequencing to explore the influences of H2S on the softening of kiwifruit. RESULTS: The firmness and the soluble solids content (SSC) of the kiwifruit were significantly better maintained with H2S treatment compared to the control during the storage period (P < 0.05). Transmission electron microscopy (TEM) showed that degradation of the cell wall was inhibited after H2S treatment. Based on transcriptome data analysis and quantitative real‐time polymerase chain reaction (qRT‐PCR), expression levels of endo‐1,4‐β‐glucanase (β‐glu), β‐galactosidase (β‐gal) and pectinesterase (PME) decreased whereas pectinesterase inhibitor (PMEI) significantly increased in response to H2S. The members of the signal transduction pathway involved in ethylene were also identified. Hydrogen sulfide inhibited the expression of ethylene receptor 2 (ETR2), ERF003, ERF5, and ERF016, and increased the expression of ethylene‐responsive transcription factor 4 (ERF4) and ERF113. CONCLUSION: Hydrogen sulfide could delay the ripening and senescence of kiwifruit by regulating the cell‐wall degrading enzyme genes and affecting ethylene signal transduction pathway genes. Our results revealed the effect of H2S treatment on the softening of kiwifruit at the transcription level, laying a foundation for further research. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The BZR serves as a key transcription factor in brassinolide signal transduction, while ethylene is known to facilitate kiwifruit softening. However, the precise mechanism by which BZR mediates the interplay between ethylene and brassinolide in fruit softening remains unclear. In this study, we identified 8 BZR transcription factors within the kiwifruit genome and conducted an analysis of their expression profiles during fruit development, post-harvest storage, and in various tissues. Subsequently, the AdBZR1.1 and AdBZR1.4 which were induced by ethylene and brassinolide respectively, were screened and identified. Subcellular localization determined that AdBZR1.1 and AdBZR1.4 were localized the nucleus. Applying four machine learning methods, we further screened for cell wall degradation genes potentially involved in fruit softening. The dual-luciferase assays revealed that AdBZR1.1 and AdBZR1.4 do not directly regulate ethylene synthesis or the screened cell wall-related genes. However, transient overexpression analysis demonstrated that AdBZR1.1 and AdBZR1.4 can promote softening of the kiwifruit. The findings from our research provide a foundation for subsequent analysis of the transcriptional regulatory networks linked to AdBZR1.1 and AdBZR1.4. • Machine learning for predicting softening gene. • AdBZR1.1 and AdBZR1.4 regulated the softening in kiwifruit. • The expression of AdBZR1.1 and AdBZR1.4 were induced by ethylene and brassinolide. [ABSTRACT FROM AUTHOR]

Harvested jujube fruit are prone to rapid ripening and softening during postharvest storage. In this work, jujube fruit were coated with xanthan gum (0.3%) and compared with uncoated control during storage at 20 ± 1 ºC for 15 d. Xanthan gum coating suppressed disease incidence (DI) and reduced fruit weight loss (FWL) of coated jujubes. Similarly, coating delayed reddening index development and suppressed relative ion leakage (RIL), malondialdehyde (MDA), superoxide anion (O 2 –•) and hydrogen peroxide (H 2 O 2) concentrations. The coated jujubes exhibited suppressed respiration and ethylene production rates along with higher antioxidative enzymes activity. On the other side, xanthan gum coating preserved higher firmness and showed lower water-soluble pectin (WSP) along with conserved concentrations of Na 2 CO 3 -soluble pectin (SSP), cellulose (CS), hemicellulose (HCS) and chelate-soluble pectin components (CSP) owing to suppressed activities of polygalacturonase (PG), cellulase (CX), pectin methylesterase (PME) and β -galactosidase (β -gal) enzymes. The coated jujubes showed reduced total soluble solids increase and exhibited higher ascorbic acid content. So, xanthan gum coating could be applied as an eco-friendly postharvest treatment for the quality preservation of fresh jujube fruit. • Xanthan gum (0.3%) delayed softening and reduced quality degradation of jujube fruit. • Coated fruit had higher chlorophyll and reduced reddening index and metabolic activities. • Treated fruit showed reduced oxidative stress and had higher antioxidant system activity. • Coated fruit had higher cell wall components and reduced softening enzyme activity. • Xanthan gum coating delayed senescence and showed better overall quality of jujube fruit. [ABSTRACT FROM AUTHOR]

Plant homeobox domain (PHD)-type transcription factors (TFs) are involved in a variety of biological processes. However, its involvement in commercially important fruit ripening process remains largely unclear. In the present work, the characterization of a PHD-type TF termed MaPHD1 from banana fruit is reported. Multiple alignments of the deduced amino acid sequence revealed that MaPHD1 showed a high homology with Arabidopsis thaliana Alfin1-like proteins belonging to plant-specific sub-family of PHD finger proteins. MaPHD1 was found localized in the nucleus and exhibited trans-repression ability. It was down-regulated by ethylene and ripening. Electrophoretic Mobility Shift Assay (EMSA) and transient expression analysis demonstrated that MaPHD1 directly bound to the G-rich motifs in the promoter of MaXTH6, which is associated with cell wall degradation, and subsequently repressed its expression. These findings suggest that MaPHD1 may be negatively associated with banana fruit ripening, at least in part, by the direct suppression of MaXTH6. Taken together, these findings provide new insights into the transcriptional regulatory networks of banana fruit ripening.

This study investigated the chemical composition (proximate and Van Soest analysis) and in vitro gas production parameters of maize leaves and stems separately, and related the in vitro gas production parameters with the chemical composition, of thirteen maize cultivars. After harvest in September 2016, all plants were separated into two morphological fractions: leaves and stems. The crude protein (CP) content was greater, and the ratio of acid detergent lignin (ADL) to potentially rumen degradable fibre (calculated as the difference between neutral detergent fibre and ADL; ADL:pRDF) was lower in the leaves than in the stems in all 13 cultivars. For the leaves, the cumulative gas production between 3 and 20 hr (A2), representing cell wall fermentation in the rumen fluid, and the cumulative 72‐hr gas production (GP72), representing total organic matter (OM) degradation, were moderately to weakly correlated with the chemical composition, including hemicellulose, cellulose, ADL and CP content (R2 < 0.40), whilst the best relationship between the half‐time value (B2), representing the rate of cell wall degradation, and chemical composition had an R2 of 0.63. For the stems, the best relationship between A2, B2 and GP72 with chemical composition was greater (R2 ≥ 0.74) and the best relationship included hemicellulose (A2 only), cellulose and ADL (GP72 and A2 only) contents. In conclusion, maize leaves and stems differed in chemical composition, in particular CP content and ADL:pRDF. The A2 and GP72 of the stems, but not of the leaves, were highly correlated with the chemical composition, indicating that the cell wall and OM degradation of maize stems can be better predicted by its chemical composition. [ABSTRACT FROM AUTHOR]

Plangoor Marian plum (Bouae burmanica) has a short harvesting period and usually harvested at fully ripe fruit stage. Therefore, the jelly-seed often occurred inside the fruit. The jelly-seed is a physiological disorder and causes fruit softening and wilting. This symptom will affect the storage period and shelf-life of the fruit. Jelly-seed also found after harvesting. This study was determined the activities of two important cell wall degradation enzymes which werepolygalacturonase (PG) and pectin methyl esterase (PME) from 3 harvesting stages of plan go fruits 75, 85 and 95 days after full bloom) DAFB. (Fruits were storage at 10 and 25°C. It was found that the jelly-seed symptom only occurred in the 95 DAFB fruits after harvest and storage at 25°C. This fruits also had the highest activity of PG. The PG activity also increased with the ripening stages and storage period. The activity of PG and PME were delayed when storage at 10°C compared with those of the fruit kept at 25°C. [ABSTRACT FROM AUTHOR]

Highlights • Chitosan and salicylic acid graft copolymer treatment reduced the green mold in fruit. • The graft copolymer application delayed fruit softening, and not impaired the fruit quality. • The graft copolymer treatment inhibited the activity and gene expression of cell wall enzymes. • The graft copolymer treatment maintained higher cell wall components in grapefruit. Abstract This study was to evaluate the effect of graft copolymer (CTS-g-SA) of chitosan (CTS) and salicylic acid (SA) on the storability of grapefruit fruits during postharvest storage. Results indicate that the graft copolymer treatment significantly depressed green mold caused by Penicillium digitatum. The graft copolymer application kept fruit firmness without impairing the fruit quality. Moreover, the graft copolymer treatment inhibited the activity and gene expression of cell wall-modifying enzymes such as polygalacturonase, cellulase, pectin methylesterase, α- l -arabinofuranosidase, β-galactosidase, and suppressed the modification of cell wall components including covalently bound polysaccharide (sodium carbonate soluble pectin, 24% KOH-soluble fraction), which were associated with fruit softening. These results suggested that graft copolymer application can be recognized as a postharvest technique to suppress rotting and delay softening through inhibiting solubilization of cell wall polysaccharides. [ABSTRACT FROM AUTHOR]

Highlights • Integrative features of cell-wall modification in berry fruit firmness were revealed. • Blackberry fruit firmness lied in levels of hydrolases and degradation of cell walls. • Blackberry fruits of similar ripening time exhibited similar initiation of softening. • Cellluase and PG played critical roles at late stages of blackberry fruit softening. Abstract Fruit flesh firmness plays a critical role in controlling blackberry (Rubus spp.) postharvest shelf life. This work aimed to identify the underlying characteristics in pericarp morphology, cell wall hydrolase activity and cell wall composition that account for flesh firmness in soft-fruited 'Boysen' and firm-fruited 'Arapaho' cultivars that have a similar ripening time of 39 days after flowering (DAF). The fruit firmness of both fruits decreased noticeably at the onset of color change, and this decrease hastened from 33 DAF to ripening despite considerable differences in their temporal changes. The evaluation of pericarp cellular morphology revealed that the disassembly of the cell wall in both fruits was likely initiated at 33 DAF, followed by extreme degradation at 39 DAF. Cell wall hydrolase activity assays indicated that increases in polygalacturonase (PG) and cellulase activity also dramatically occurred in the late softening stages of both fruits. Notably, appreciably higher levels of cellulase, and significant increases in pectin methylesterase (PME), α-L-arabinofuranosidase (α-L-Af) and xyloglucan endotransglycosylase (XET) were only detected in the late ripening stages of 'Boysen'. In terms of cell wall components, the levels of cell wall material (CWM), cellulose and hemicellulose declined similarly during ripening in both fruits. Comparatively, lower levels of CWM, chelator soluble pectin (CSP), sodium carbonate soluble pectin (SSP), and hemicellulose as well as higher levels of water soluble pectin (WSP) were found in 'Boysen' than those in 'Arapaho' during maturation and ripening. Overall, the loss of fruit firmness during ripening in blackberry fruit is correlated closely with biochemical changes in cell wall fractions that involve hydrolytic processes, resulting in the breakdown of cell-wall polymers. The low firmness of 'Boysen', as determined by cell wall degradation, could be of particular relevance to the function of cell wall degrading enzymes and to the more drastic degradation of cell wall components than that in the firm cv. 'Arapaho'. [ABSTRACT FROM AUTHOR]