Low Temperature (15 °C) Reduces Bacterial Diversity and Prolongs the Preservation Time of Volvariella volvacea

Long non-coding RNAs and their potential function in response to postharvest senescence of Sparassis latifolia during cold storage

Long non-coding RNAs (lncRNAs) have been shown to play crucial roles in response to aging processes. However, how lncRNAs regulate postharvest senescence of Sparassis latifolia (S. latifolia) with oriented polypropylene (OPP) film packing during cold storage remains unclear. In this study, we performed RNA-seq using the fruiting bodies of S. latifolia stored at 4 ℃ for 0, 8, 16 and 24 days after harvest, and profiled the lncRNA and mRNA transcriptome, respectively. In total, 1003 putative lncRNAs were identified, and there were 495, 483 and 162 differentially expressed (DE) lncRNAs, and 3680, 3941 and 1870 differentially expressed mRNAs after 8, 16 and 24 days of storage, respectively, compared to 0 day of storage. Target genes of differentially expressed lncRNAs were found to significantly associate with carbon and energy metabolism, response to abiotic stimulus, amino acid biosynthesis and metabolism, and protein synthesis and transcription. In addition, DE-lncRNA-mRNA co-expression networks in response to aging stress were also constructed. Taken together, these results confirm the regulatory role of lncRNAs in postharvest senescence of S. latifolia and will facilitate for improving preservation method.

Review of postharvest processing of edible wild-grown mushrooms

Edible wild-grown mushrooms, plentiful in resources, have excellent organoleptic properties, flavor, nutrition, and bioactive substances. However, fresh mushrooms, which have high water and enzymatic activity, are not protected by cuticles and are easily attacked by microorganisms. And wild-grown mushroom harvesting is seasonal the harvest of edible wild-grown mushrooms is subject to seasonality, so their market availability is challenging. Many processing methods have been used for postharvest mushroom processing, including sun drying, freezing, packaging, electron beam radiation, edible coating, ozone, and cooking, whose effects on the parameters and composition of the mushrooms are not entirely positive. This paper reviews the effect of processing methods on the quality of wild and some cultivated edible mushrooms. Drying and cooking, as thermal processes, reduce hardness, texture, and color browning, with the parallel that drying reduces the content of proteins, polysaccharides, and phenolics while cooking increases the chemical composition. Freezing, which allows mushrooms to retain better hardness, color, and higher chemical content, is a better processing method. Water washing and ozone help maintain color by inhibiting enzymatic browning. Edible coating facilitates the maintenance of hardness and total sugar content. Electrolytic water (EW) maintains total phenol levels and soluble protein content. Pulsed electric field and ultrasound (US) inhibit microbial growth. Frying maintains carbohydrates, lipids, phenolics, and proteins. And the mushrooms processed by these methods are safe. They are the focus of future research that combines different methods or develops new processing methods, molecular mechanisms of chemical composition changes, and exploring the application areas of wild mushrooms.

Dynamic Microbiome Changes Reveal the Effect of 1-Methylcyclopropene Treatment on Reducing Post-harvest Fruit Decay in "Doyenne du Comice" Pear

Pathogen-induced decay is one of the most common causes of fruit loss, resulting in substantial economic loss and posing a health risk to humans. As an ethylene action inhibitor, 1-methylcyclopropene (1-MCP) can significantly reduce fruit decay, but its effect on fruit pathogens remains unclear. Herein, the change in microbial community structure was analyzed using the high-throughput sequencing technology, and characteristics related to fruit quality were determined after 1-MCP (1.0 M l L-1) treatment in "Doyenne du Comiceis" pear fruit during storage at ambient temperature. Overall, 1-MCP was highly effective in reducing disease incidence and induced multiple changes of the fungal and bacterial microbiota. At day 15, the microbial diversity of fungi or bacteria was reduced significantly in the control fruit (non-treated with 1-MCP), which had the most severe decay incidence. For fungi, in addition to Alternaria being the most abundant in both 1-MCP treatment (59.89%) and control (40.18%), the abundances of Botryosphaeria (16.75%), Penicillium (8.81%), and Fusarium (6.47%) increased significantly with the extension of storage time. They became the primary pathogens to cause fruit decay in control, but they were markedly decreased in 1-MCP treatment, resulting in reduced disease incidence. For bacteria, the abundance of Gluconobacter (50.89%) increased dramatically at day 15 in the control fruit, showing that it also played a crucial role in fruit decay. In addition, Botryosphaeria, Fusarium fungi, and Massilia, Kineococcus bacteria were identified as biomarkers to distinguish 1-MCP treatment and control using Random Forest analysis. The redundancy analysis (RDA) result showed that the amount of Botryosphaeria, Penicillium, and Fusarium were positively correlated with disease incidence and respiration rate of pear fruits while negatively correlated with fruit firmness. This investigation is the first comprehensive analysis of the microbiome response to 1-MCP treatment in post-harvest pear fruit, and reveals the relationship between fruit decay and microbial composition in pear fruit.

Microflora and umami alterations of different packaging material preserved mushroom (Flammulina filiformis) during cold storage

In order to clarify the effect of nanocomposite-based packaging (NP) on umami and microflora characteristics of F. filiformis during cold storage, the contents of umami amino acids and 5'-nucleotides, equivalent umami concentration (EUC), and microflora succession were investigated. Results showed that NP could delay the degradation of umami components and inhibit bacterial growth in F. filiformis. At the initial stage, the dominant bacteria were Lactobacillus, Thermus and Acinetobacter. After 15 days of storage, the bacteria count in NP reached 7.63 lg cfu/g, which was significantly (P < 0.05) lower than that in control, and the major bacterial communities of packaged F. filiformis were Ewingella, Serratia and Pseudomonas. Moreover, the correlation analysis showed that Lactobacillus, Brevibacillus and Okibacterium were negatively correlated with AMP and IMP 5-nucleotides. Present work suggested that NP could enhance the umami flavor formation and improve the microbial community structure of F. filiformis, resulting in a better commercial quality. The results provided theoretical basis for large-scale applications of NP.