Transcriptomic and physiological analysis reveals the possible mechanism of ultrasound inhibiting strawberry (Fragaria × ananassa Duch.) postharvest softening

Preparation of chitosan/polyvinyl alcohol antibacterial indicator composite film loaded with AgNPs and purple sweet potato anthocyanins and its application in strawberry preservation

This study incorporated purple sweet potato anthocyanin (PSPA) and silver-nanoparticles (AgNPs) into the chitosan/polyvinyl alcohol film matrix (PVA/CS) to successfully prepare a composite film, which effectively inhibited bacterial growth and indicated product freshness. The addition of AgNPs and PSPA led to a dense structure of the film, which effectively enhanced its physical properties, barrier properties and functional properties. The incorporation of PSPA made the composite film highly pH-sensitive, which exhibited distinct color changes in varying pH solutions. The PVA/CS-AgNPs-PSPA10 composite film with PSPA and AgNPs resulted the shelf life of strawberries to 13 days at 4 °C, which effectively reduced strawberry breathing during storage. Additionally, such composite film changed color from purple to yellow-purple, indicating the deterioration of strawberries. It also showed an antibacterial indication through its excellent antibacterial property and freshness indication performance, which demonstrated its significance in developing antibacterial indicator composite packaging materials for fruits and vegetables preservation.

Effects of gnotobiotic fermentation on global gene expression of germ-free vegetables

Existing research has underscored the vital interplay between host organisms and their associated microbiomes, which affects health and function. In both plants and animals, host factors critically shape microbial communities and influence growth, health, and immunity. Post-harvest plants, such as those used in kimchi, a traditional Korean dish, offer a unique avenue for exploring host-microbe dynamics during fermentation. Despite the emphasis on lactic acid bacteria (LAB) in fermentation studies, the roles of host factors remain unclear. This study aimed to investigate the influence of these factors on plant transcriptomes during kimchi fermentation. We individually inoculated nine LAB strains into germ-free kimchi to generate LAB-mono-associated gnotobiotic kimchi and performed RNA-sequencing analysis for the host vegetables during fermentation. The transcriptomes of post-harvest vegetables in kimchi change over time, and microbes affect the transcriptome profiles of vegetables. Differentially expressed gene analyses revealed that microbes affected the temporal expression profiles of several genes in the plant transcriptomes in unique directions depending on the introduced LAB strains. Cluster analysis with other publicly available transcriptomes of post-harvest vegetables and fruits further revealed that the plant transcriptome is more profoundly influenced by the environment harboring the host than by host phylogeny. Our results bridge the gap in understanding the bidirectional relationship between host vegetables and microbes during food fermentation, illuminating the complex interplay between vegetable transcriptomes, fermentative microbes, and the fermentation process in food production. The different transcriptomic responses elicited by specific LAB strains suggest the possibility of microbial manipulation to achieve the desired fermentation outcomes.

Transcriptomic and Physiological Analysis Reveals the Possible Mechanism of Inhibiting Strawberry Aroma Changes by Ultrasound after Harvest

The volatile compounds in strawberries play a significant role in the formation of strawberry aroma. However, these compounds undergo continual changes during storage, resulting in a decline in quality. In this study, a total of 67 volatile organic compounds (VOCs) were identified in strawberries through quantitative analysis. At the end of the storage period, the VOC content in the ultrasonic group was 119.02 µg/kg higher than that in the control group. The results demonstrated that the ultrasonic treatment increased the contents of terpenes and esters at the end of storage. Among these, linalool increased from 67.09 to 91.41 µg/kg, while ethyl cinnamate increased from 92.22 to 106.79 µg/kg. Additionally, the expression of the key metabolic genes closely related to these substances was significantly up-regulated. The expression of the FaNES gene, related to terpene metabolism, was up-regulated by 2.8 times in the second day, while the expression of the FaAAT gene, related to ester metabolism, was up-regulated by 1.5 times. In summary, this study provides a theoretical basis for exploring the mechanism of ultrasonic effect on strawberry flavor and quality after harvest.

Effects of atrazine on movement, metabolism and gene expression in Pelophylax nigromaculatus larvae under global warming

Global warming and environmental pollutants both pose a threat to the behavior and physiology of animals, but research on the combined effects of the two is limited. Atrazine, a widely used herbicide, has toxic effects on organisms. In this study, the effects of environmental concentrations of atrazine exposure (100 μg/L) for seven days on the movement, metabolism and gene expression related to motility of Pelophylax nigromaculatus larvae (GS8) were investigated under global warming. The results showed that compared to the optimal growth temperature (18 °C), atrazine treatment under global warming (21 °C) significantly increased the average speed (about 11.2 times) and maximum acceleration (about 1.98 times) of P. nigromaculatus larvae, altered the relative abundance of 539 metabolites, including Formyl-5-hydroxykynurenamine, 2,4-Dihydroxybenzophenone, and FAPy-adenine, and changed the nucleotide metabolism, pyrimidine metabolism, glycerophospholipid metabolism, and purine metabolism, as well as increased the gene expression of SPLA2 (about 6.46 times) and CHK (about 3.25 times). In summary, atrazine treatment under global warming caused metabolic disorders in amphibian larvae and increased the expression of some movement-related genes in the brain, resulting in abnormally active.

Effect of exogenous melatonin on antioxidant properties and fruit softening of 'Fengtang' plum fruit (Prunus salicina Lindl.) during storage at room temperature

'Fengtang' plums soften quickly and lose flavor after harvest. This study comprehensively evaluated the effect of exogenous melatonin on the fruit quality of 'Fengtang' plums. According to our findings, exogenous melatonin prevented plum fruit from losing water, delayed the decline in firmness, and preserved a high TSS/TA level. Additionally, exogenous melatonin also enhanced the activity of antioxidant enzymes and increased the non-enzymatic antioxidants, thereby further increasing the antioxidant capacity of plum fruit. Notably, exogenous melatonin delayed the degradation of covalent soluble pectin (CSP), cellulose, and hemicellulose, as well as the rise in water-soluble pectin (WSP) concentration and the activity of cell wall degrading enzymes. Further investigation using atomic force microscopy (AFM) revealed that the chain-like structure of ionic-soluble pectin (ISP) and the self-assembly network structures of CSP were depolymerized, and melatonin treatment retarded the depolymerization of pectin structures. Our results showed that exogenous melatonin preserved the postharvest quality of plum fruits by controlling fruit softness and antioxidant capacity during storage.

Phased gap-free genome assembly of octoploid cultivated strawberry illustrates the genetic and epigenetic divergence among subgenomes

The genetic and epigenetic mechanisms underlying the coexistence and coordination of the four diverged subgenomes (ABCD) in octoploid strawberries (Fragaria × ananassa) remains poorly understood. In this study, we have assembled a haplotype-phased gap-free octoploid genome for the strawberry, which allowed us to uncover the sequence, structure, and epigenetic divergences among the subgenomes. The diploid progenitors of the octoploid strawberry, apart from subgenome A (Fragaria vesca), have been a subject of public controversy. Phylogenomic analyses revealed a close relationship between diploid species Fragaria iinumae and subgenomes B, C, and D. Subgenome A, closely related to F. vesca, retains the highest number of genes, exhibits the lowest content of transposable elements (TEs), experiences the strongest purifying selection, shows the lowest DNA methylation levels, and displays the highest expression level compared to the other three subgenomes. Transcriptome and DNA methylome analyses revealed that subgenome A-biased genes were enriched in fruit development biological processes. In contrast, although subgenomes B, C, and D contain equivalent amounts of repetitive sequences, they exhibit diverged methylation levels, particularly for TEs located near genes. Taken together, our findings provide valuable insights into the evolutionary patterns of subgenome structure, divergence and epigenetic dynamics in octoploid strawberries, which could be utilized in strawberry genetics and breeding research.