Chilling stress reduced protein translation by the ubiquitination of ribosomal proteins in Volvariella volvacea

Synergizing postharvest physiology and nanopackaging for edible mushroom preservation

The cultivation of edible mushrooms is increasing because of their widely recognized nutritional benefits. Advancements in cultivation techniques have facilitated large-scale mushroom production, meeting the growing consumer demand. This rise in cultivation has led to an increasingly urgent demand for advanced postharvest preservation methods to extend the shelf life of these mushrooms. The postharvest preservation of fresh edible mushrooms involves complex physiological changes and metabolic activities closely associated with gas composition, microbial presence, moisture content, ambient temperature, and enzymatic activity. Preserving edible mushrooms through various preservation strategies (physical, chemical, biological, and nanopackaging approaches) relies on regulating postharvest factors. Nanopackaging can preserve mushrooms' sensory and nutritional qualities due to the specific characteristics of nanomaterials, such as antimicrobial properties and gas/moisture barriers. Furthermore, the review explores current trends, fundamental mechanisms, and upcoming challenges in utilizing nanomaterials, particularly their capacity to enhance the "cell wall" integrity of edible mushrooms by regulating postharvest factors.

Potential Role of Lysine Acetylation and Autophagy in Brown Film Formation and Postripening of Lentinula edodes Mycelium

Lentinula edodes is one of the most widely cultivated edible mushrooms in the world. When cultivated in sawdust, the surface mycelium of L. edodes needs a long postripening stage wherein it forms a brown film (BF) by secreting and accumulating pigments. BF formation is critical for the high quality and yield of fruiting bodies. Protein lysine acetylation (KAC) is an important post-translational modification that regulates growth and development. Previous studies have shown that deacetylase levels are significantly increased during BF formation in the postripening stage of L. edodes. The aim of this study was to assess the role of protein acetylation during BF formation. To this end, we compared the acetylome of L. edodes mycelia before and after BF formation using anti-acetyl antibody-based label-free quantitative proteomics. We identified 5,613 acetylation sites in 1,991 proteins, and quantitative information was available for 4,848 of these sites in 1,815 proteins. Comparative acetylome analysis showed that the modification of 699 sites increased and that of 562 sites decreased during BF formation. Bioinformatics analysis of the differentially acetylated proteins showed significant enrichment in the tricarboxylic acid (TCA) cycle and proteasome pathways. Furthermore, functional assays showed that BF formation is associated with significant changes in the activities of proteasome, citrate synthase, and isocitrate dehydrogenase. Consistent with this hypothesis, the lysine deacetylase inhibitor trichostatin (TSA) delayed autophagy and BF formation in L. edodes. Taken together, KAC and autophagy play important roles in the mycelial BF formation and postripening stage of L. edodes. IMPORTANCE Mycelial BF formation and postripening of L. edodes affects the quality and quantity of its edible fruiting bodies. In this study, we explored the role of protein KAC in this biological process, with the aim of optimizing the cultivation and yield of L. edodes.

VyUSPA3, a universal stress protein from the Chinese wild grape Vitis yeshanensis, confers drought tolerance to transgenic V. vinifera

VyUSPA3 from the Chinese wild grape Vitis yeshanensis interacts with ERF105, PUB24 and NF-YB3, and overexpression of the VyUSPA3 gene in V. vinifera cv. 'Thompson Seedless' confers drought tolerance. Drought is a major abiotic stress factor that seriously affects the growth and yield of grapevine. Although many drought-related genes have been identified in Arabidopsis and other plants, the functions of only a few of their counterparts have been revealed in grape. Here, a universal stress protein (USP) A from the Chinese wild grape Vitis yeshanensis, VyUSPA3, was identified and its function was subsequently characterized by overexpressing or silencing the VyUSPA3 gene in V. vinifera cv. 'Thompson Seedless' via Agrobacterium-mediated genetic transformation. After 21 d of the drought treatment, most leaves of the untransformed (UT) 'Thompson Seedless' lines wilted, yet UT lines were less damaged compared to the RNAi-VyUSPA3 lines, nonetheless, the OE-VyUSPA3 lines were mostly unaffected. Meanwhile, OE-VyUSPA3 lines showed smaller stomatal aperture, more developed roots, higher leaf relative water content, proline content, and antioxidant enzyme activities, as well as lower malondialdehyde, H₂O₂ and O₂^•- accumulation than UT lines, but this response pattern was reversed in the RNAi-VyUSPA3 lines. Besides, the transcript levels of four drought-related genes (RD22, RD29B, DREB2A, and NCED1) in OE-VyUSPA3 lines were greater than those in the RNAi-VyUSPA3 and UT lines. In addition, a yeast two-hybrid assay and a bimolecular fluorescence complementation assay confirmed that VyUSPA3 interacted with ERF105, PUB24, and NF-YB3, respectively. This study revealed that VyUSPA3 improved drought tolerance in transgenic grapevines possibly through interaction with the hormone signaling, ubiquitination system, ethylene-responsive element binding factor and nuclear factors.

PseAraUbi: predicting arabidopsis ubiquitination sites by incorporating the physico-chemical and structural features

We makes three kinds of important features from Arabidopsis thaliana: protein secondary structure based on the Chou-Fasman parameter, amino acids hydrophobicity and polarity information, and analyze their properties. Ubiquitination modification is an important post-translational modification of proteins, which participates in the regulation of many important life activities in cells. At present, ubiquitination proteomics research is mostly concentrated in animals and yeasts, while relatively few studies have been carried out in plants. It can be said that the calculation and prediction of Arabidopsis thaliana ubiquitination sites is still in its infancy. Based on this, we describe a calculation method, PseAraUbi (Prediction of Arabidopsis thaliana ubiquitination sites using pseudo amino acid composition), that can effectively detect ubiquitination sites on Arabidopsis thaliana using support vector machine learning classifiers. Based on protein sequence information, extract features from the Chou-Fasman parameter, amino acids hydrophobicity features, polarity information and selected for classification with the Boruta algorithm. PseAraUbi achieves promising performances with an AUC score of 0.953 with fivefold cross-validation on the training dataset, which are significantly better than that of the pioneer Arabidopsis thaliana ubiquitination sites method. We also proved the ability of our proposed method on independent test sets, thus gaining a competitive advantage. In addition, we also in-depth analyzed the physicochemical properties of amino acids in the region adjacent to the ubiquitination site. To facilitate the community, the source code, optimal feature subset, ubiquitination sites dataset in the Arbidopsis proteome are available at GitHub ( https://github.com/HNUBioinformatics/PseAraUbi.git ) for interest users.

Multi-Approach Analysis Reveals Pathways of Cold Tolerance Divergence in Camellia japonica

Understanding the molecular mechanism of the cold response is critical to improve horticultural plant cold tolerance. Here, we documented the physiological, transcriptome, proteome, and hormonal dynamics to cold stress in temperate genotype (Tg) and subtropical genotype (Sg) populations of Camellia japonica. Tg C. japonica suffered minimal osmotic and oxidative damage compared to Sg C. japonica under the same cold treatment. Transcriptional and translational differences increased under the cold treatment, indicating that Tg C. japonica was affected by the environment and displayed both conserved and divergent mechanisms. About 60% of the genes responding to cold had similar dynamics in the two populations, but 1,896 transcripts and 455 proteins differentially accumulated in response to the cold between Tg and Sg C. japonica. Co-expression analysis showed that the ribosomal protein and genes related to photosynthesis were upregulated in Tg C. japonica, and tryptophan, phenylpropanoid, and flavonoid metabolism were regulated differently between the two populations under cold stress. The divergence of these genes reflected a difference in cold responsiveness. In addition, the decrease in the abscisic acid (ABA)/gibberellic acid (GA) ratio regulated by biosynthetic signal transduction pathway enhanced cold resistance in Tg C. japonica, suggesting that hormones may regulate the difference in cold responsiveness. These results provide a new understanding of the molecular mechanism of cold stress and will improve cold tolerance in horticultural plants.

Transcriptome analysis of genes associated with autolysis of Coprinus comatus

Coprinus comatus, widely known as "Jituigu", is an important commodity and food in China. The yield of C. comatus, however, is substantially reduced by the autolysis of the fruiting bodies after harvest. To gain insight into the molecular mechanism underlying this autolysis, we divided the growth of C. comatus fruiting bodies into four stages: infant stage (I), mature stage (M), discolored stage (D), and autolysis stage (A). We then subjected these stages to de novo transcriptomic analysis using high-throughput Illumina sequencing. A total of 12,946 unigenes were annotated and analyzed with the Gene Ontology (GO), Clusters of Orthologous Groups of proteins (COG), and Kyoto Encyclopedia of Genes and Genomes (KEGG). We analyzed the differentially expressed genes (DEGs) between stages I and M, M and D, and D and A. Because the changes from M to D are thought to be related to autolysis, we focused on the DEGs between these two stages. We found that the pathways related to metabolic activity began to vary in the transition from M to D, including pathways named as autophagy-yeast, peroxisome, and starch and sucrose metabolism. This study also speculates the possible process of the autolysis of Coprinus comatus. In addition, 20 genes of interest were analyzed by quantitative real-time PCR to verify their expression profiles at the four developmental stages. This study, which is the first to describe the transcriptome of C. comatus, provides a foundation for future studies concerning the molecular basis of the autolysis of its fruiting bodies.

The cold - resistance mechanism of a mutagenic Volvariella volvacea strain VH3 with outstanding traits revealed by transcriptome profiling

Background

The straw mushroom (Volvariella volvacea) is one of the important vegetables that is popular for its delicious taste. However, the straw mushroom is sensitive to low temperature, resulting in economic loss during transportation and storage. We obtained a novel straw mushroom strain, named VH3, via ultraviolet mutagenesis.

Results

Our study revealed that VH3 exhibited high cold resistance compared to an ordinary straw mushroom cultivar, V23. We found that the electrolyte leakages of VH3 were always significantly lower than that of V23 treated with 4 °C for 0 h, 2 h,4 h, 8 h, 16 h, and 24 h. Before cold treatment (0 h), there were no difference of MDA contents, SOD activities, and CAT activities between VH3 and V23. At the late stage (8 h, 26 h, and 24 h) of cold treatment, the MDA contents of VH3 were lower while both the SOD and CAT activities were higher than those of V23. To investigate the potential mechanisms of VH3 cold resistance, we performed transcriptome sequencing to detect the transcriptome profiling of VH3 and V23 after 0 h and 4 h cold treatment. Transcriptome sequencing revealed that 111 differentially expressed genes (DEG) between V23 (0 h) and VH3 (0 h) (V23–0_vs_VH3–0), consisting 50 up-regulated and 61 down-regulated DEGs. A total of 117 DEGs were obtained between V23 (4 h) and VH3(4 h) (V23–4_vs_VH3–4), containing 94 up-regulated and 23 down-regulated DEGs. Among these DEGs, VVO_00021 and VVO_00017 were up-regulated while VVO_00003, VVO_00004, VVO_00010, and VVO_00030 were down-regulated in V23–0_vs_VH3–0 and VH3–4_vs_V23–4. KEGG and GO analysis revealed that the 6 DEGs were annotated to pathways related to cold stress. Besides, the GA3 content was also decreased in VH3.

Conclusions

Collectively, our study first revealed that the increased cold resistance of VH3 might be caused by the expression change of VVO_00003, VVO_00004, VVO_00017, VVO_00021, and VVO_00030, and decreased GA₃.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02396-8.

Molecular characterization of ubiquitin-conjugating enzyme gene ube2h and siRNA-mediated regulation on targeting p53 in turbot, Scophthalmus maximus

Ubiquitin-conjugating enzymes are key factors in the ubiquitin proteasome pathway (UPP), which play key roles in ubiquitination. These enzymes affect the efficiency of UPP during stress conditions. P53 has important control of cell cycle arrest and apoptosis in response to cellular stress; these modifications are critical for the stability and transcriptional activity of p53 as the protein activates downstream target genes that dictate the cellular response. However, few studies have investigated the effects of thermal stress in turbot (Scophthalmus maximus), specifically the UPP signaling pathway, and the crosstalk between the ube2h and p53. In this study, the rapid amplification of cDNA ends was used to obtain a full-length cDNA of the turbot UBE2H gene (Sm-ube2h) and perform bioinformatics analysis. Our results showed that the cDNA of the Sm-ube2h was 718 bp in length, encoding a 189 amino acid protein, with a theoretical isoelectric point of 4.77. It also contained a catalytic (UBCc) domain. Expression of Sm-ube2h in different tissues was detected and quantified by qPCR, which was highest in the spleen and lowest in the liver. We also investigated the Sm-ube2h expression profiles in the liver and heart after thermal stress, and changes in Sm-ube2h and p53 under thermal stress, upon RNA interference. Our data speculated that Sm-ube2h and p53 exhibited antagonistic effects under normal temperature conditions after ube2h interference, but displayed synergistic effects under thermal stress, suggesting the crosstalk between UPP and p53 signaling pathway. Our results improved our understanding of the underlying molecular mechanism of thermal tolerance in turbot.

Chilling Stress Triggers VvAgo1-Mediated miRNA-Like RNA Biogenesis in Volvariella volvacea

In Volvariella volvacea, an important species of edible mushroom, cryogenic autolysis is a typical phenomenon that occurs during abnormal metabolism. Analysis of gene expression profiling and qPCR showed that chilling stress (CS) significantly and continuously upregulated only one type of Argonaute in V. volvacea, i.e., VvAgo1. Structural and evolutionary analysis revealed that VvAgo1 belongs to the Ago-like family, and its evolution has involved gene duplication, subsequent gene loss, and purifying selection. Analysis of its interaction network and expression suggested that CS triggers VvAgo1-mediated miRNA-like RNA (milRNA) biogenesis in V. volvacea V23 but not in VH3 (a composite mutant strain from V23 with improved CS resistance). Small RNA sequencing and qPCR analysis confirmed that CS triggered the increased milRNA expression in V23 and not in VH3. The predicted target genes of the increased milRNAs were enriched in several pathways, such as signal transduction and ubiquitination. Heatmap analysis showed that CS altered the expression profile of milRNAs with their target genes related to signal transduction and ubiquitination in V23. Combined analysis of transcriptome and proteome data confirmed that most of the target genes of the increased milRNAs were not translated into proteins. Our observations indicate that CS might trigger VvAgo1-mediated RNAi to facilitate the cryogenic autolysis of V. volvacea.