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A comparative study was carried out on the chemical composition and nutritional value of six cultivated Lentinula edodes strains that are widely appreciated in China. The results demonstrated that all investigated L. edodes were good sources of protein (14.87%-27.13%), carbohydrates (62.03%-75.56%), and dietary fiber (35.88%-42.49%) and had low ash (5.24%-6.38%) and low fat (0.80%-1.70%) content. There were significant differences among different cultivars. Shenxiang 215 had high crude protein and dietary fiber contents. Potassium was the most abundant mineral element, followed by phosphorus. Different cultivars exhibited distinct fatty acid compositions and free amino acid profiles. Shenxiang 215 had high essential amino acid content. Polyunsaturated fatty acids were predominant in cultivars 0912, Huxiang F4, and Huxiang F2; however, monounsaturated fatty acids were predominant in other strains. Cultivar 0912 had a better mineral and polyunsaturated fatty acid profile. The amino acid profile and protein quality were systematically investigated referring to the latest version of international amino acid reference patterns, including the amino acid score, ratio coefficient of amino acid, ratio coefficient score of amino acid, essential amino acid index, and protein digestibility - corrected amino acid score. The results demonstrated that Shenxiang 18 had better protein quality. These findings provide a reference for breeders to select parents for directional quality breeding.

Polysaccharides separated from Lentinula edodes are well known for their medicinal properties. However, the precise molecular mechanisms of polysaccharide biosynthesis in L. edodes remain unclear. In this study, the fruiting bodies of L. edodes in four developmental stages with significant differences in polysaccharide yield were collected, and the characteristics of polysaccharides were studied. De novo sequencing and comparative transcriptomic analysis were performed by using high-throughput Illumina RNA-sequencing. KS1P30, KS2P30, KS3P30, and KS4P30 were obtained from the four developmental stages, respectively, by hot water extraction and 30% ethanol precipitation. These four polysaccharides had good immune activity in vitro; all of them were β-glucopyranose with a high molecular weight. Glucose was the main monosaccharide component of these polysaccharides. High-quality clean reads (57.88, 53.17, 53.28, and 47.56 million for different growth stages) and mapping ratios ranging from 84.75 to 90.11% were obtained. In total, 11,493 (96.56%) unigenes and 18,924 (97.46%) transcripts were successfully annotated in five public databases. The biosynthetic pathway and related genes of LEFP30 were mined. The molecular mechanism of LEFP30 yield change in the different developmental stages was predicted. The results provide some insights into the possible mechanisms involved in the biosynthetic pathway of this kind of polysaccharide in L. edodes fruiting bodies. They also indicate that candidate genes can be used as important resources for biotechnology and molecular breeding to regulate L. edodes fruiting body polysaccharide biosynthesis.

Saccharopine dehydrogenase (EC 1.5.1.7) regulates the last step of fungal lysine biosynthesis. The gene (Fvsdh) encoding saccharopine dehydrogenase was identified and cloned from the whole genome of Flammulina velutipes. The genomic DNA of Fvsdh is 1257 bp, comprising three introns and four exons. The full-length complementary DNA of Fvsdh comprises 1107 bp with a deduced amino acid sequence of 368 residues. A 1,000-bp promoter sequence containing the TATA box, CAAT box, and several putative cis-acting elements was also identified. The results of tissue expression analysis showed that the expression level of the Fvsdh gene was higher in the pileus than in the stipe whether in the elongation or maturation stage. Further research showed that the lysine contents were 3.03 and 2.95 mg/g in maturation-pileus and elongation-pileus, respectively. In contrast, the lysine contents were 2.49 and 2.07 mg/g in elongation-stipe and maturation-stipe, respectively. To study the function of Fvsdh, we overexpressed Fvsdh in F. velutipes and found that Fvsdh gene expression was increased from 1.1- to 3-fold in randomly selected transgenic strains. The lysine contents were also increased from 1.12- to 1.3-fold in these five transformants, except for strain T3, in which the lysine contents were the same as the control. These results indicate that the expression of the Fvsdh gene can affect the lysine content of F. velutipes.

Background: Coronavirus disease 2019 (COVID-19) patients suffer from anxiety, depression, and sleep disorder due to isolation treatment and other reasons. Whether life interventions can be an alternative therapy for COVID-19 patients, accompanied with anxiety, depression, and sleep disorder, is controversial. Therefore, we conducted a meta-analysis and systematic review to evaluate the effects of life interventions on anxiety, depression, and sleep disorder in COVID-19 patients to provide some guidance for clinical application. Methods: The randomized controlled trials related to the life intervention and COVID-19 from inception to February 2021 will be searched. The following databases are our focused areas: the Cochrane Central Register of Controlled Trials, PubMed, MEDLINE, EMBASE, Web of Science, China National Knowledge Infrastructure, Chinese Biomedical Literature Database, and Wan Fang Database. Two investigators would independently screen the literature according to the inclusion and exclusion criteria, extract data, and evaluate the risk of bias in the included studies. Meta-analysis was performed with RevMan 5.3 software. Results: The results will provide a high-quality synthesis of current evidence for researchers in this subject area. Conclusion: The conclusion of our study will provide evidence for the judgment of whether life intervention is an effective intervention on COVID-19 patients. PROSPERO registration number: CRD42020199802.

Lack of an efficient transformation system has hampered the molecular breeding of Agaricus bisporus . Here, we describe a highly efficient Agrobacterium-mediated transformation system for A. bisporus using foxtail millet (Setaria italica L. Beauv) grains as cultivation and infection media. Mycelium-millet complexes were prepared for co-culture and treated with ultrasonication for 10 s to improve infection efficiency. After a 72-h culture period, the newly grown mycelium-surrounded millet grain was transferred to selection medium supplemented with 200 μg/mL cefotaxime and 15 μg/mL hygromycin B (hyg) to screen positive transformants. Putative transformants were analyzed for the presence of the hyg gene by polymerase chain reaction and Southern blotting. Expression of eGFP in A. bisporus transformants was detected by fluorescence imaging, and the β-glucuronidase (GUS) protein was detected by histochemical staining. Our protocol resulted in an average 53.85% transformation frequency, and over 85% of the transformants tested remained mitotically stable, even after five successive rounds of subculturing. A feasible method for A. bisporus mushroom transformation using foxtail millet as an innovative culture medium was developed, which will benefit future functional genetic studies of this mushroom.