Study On The Biologicaland Formed Characteristics Of Abnormal Phenotypic Strains In Lentinula Edodes Production

Lentinula edodes is the highest annual production of edible mushroom in China.Due to the degradation or aging of the strain,mycelia of L.edodes cultivation bags often experience problems such as slow mycelial growth,abnormal discoloration,reduced or malformed fruiting body formation,causing significant economic losses to the L.edodes industry.This study analyzed the biological characteristics and formation characteristics of several abnormal strains(Myc-W,SX12-W,SZ-W,SLG)discovered during L.edodes production.The main results obtained are as follows:Biological characteristics of L.edodes strain with abnormal phenotypes.Compared with healthy strains,the mycelial growth rate of abnormal Myc-W and SX12-W strains was significantly slower,while the SZ-W and SLG strains did not show a significant change in mycelial growth rate.SEM observations found that all abnormal L.edodes strains had different degrees of mycelial knotting,swelling,desiccation,and wrinkling.TEM observations showed varying degrees of cytoplasmic leakage,vacuolization,thickening of the cell walls,and degradation of cellular contents.In addition,all abnormal L.edodes strains showed weaker recovery ability after exposured to high-temperature stress at 38℃ for 24 hours compared to their control strains.The above phenotypic features were evident for Myc-W and SX12-W,while SZ-W and SLG showed slightly weaker performance.Transcriptome information analysis was conducted to identify metabolic pathways or genes related to the abnormal phenotype.In terms of carbon metabolism,compared to the normal strain Myc-G,all differentially expressed genes in the pyruvate and tricarboxylic acid cycle metabolic pathways were significantly upregulated in the abnormal strain Myc-W,while all differentially expressed genes in the starch and sucrose metabolic pathways were significantly downregulated.In the amino acid metabolic pathway,most differentially expressed genes in the glycine-serine-threonine metabolic pathway were significantly upregulated in Myc-W;while genes encoding tyrosine aminotransferase,4-hydroxy-2-oxoglutarate aldolase,succinate semialdehyde dehydrogenase,and polyamine oxidase were significantly downregulated in the tyrosine metabolic pathway;and genes encoding amidase and aldehyde dehydrogenase were significantly downregulated in the tryptophan metabolic pathway.In the biosynthesis of unsaturated fatty acids metabolic pathway,all differentially expressed genes in Myc-W were significantly upregulated.Additionally,several differentially expressed genes related to cell apoptosis,cell senescence,autophagy,and stress response were also identified.Based on the analysis results,30 other functionally relevant genes with large differential expression ratios involving cell wall,cell membrane,cell apoptosis,oxidative stress,and stress response were selected for validation.The results showed that,compared to the normal strain,there were consistent expression trends in 26,18,and 20 differentially expressed genes in SX12-W,SZ-W,and SLG,respectively,which were similar to the expression trends observed in Myc-G vs Myc-W.Physiological and biochemical index measurements and functional analysis of theΔ12 fatty acid dehydrogenase gene verified some of the above excavation clues.Chitin,β-1,3-glucan content,electrical conductivity and fatty acid unsaturation were significantly higher in Myc-W and SX12-W than in their corresponding normal control strains,ATP content,tyrosinase enzyme activity and melanin content were reduced.Functional analysis of Δ12 fatty acid dehydrogenase gene(FAD2,Δ12 fatty acid desaturase,gene＿30437),a key enzyme gene in fatty acid biosynthesis,showed that the Le FAD2 gene affects the heat resistance of L.edodes strains by influencing the unsaturation degree and membrane fluidity of fatty acids.In summary,the analysis shows that abnormal L.edodes strains exhibit distinct gene expression characteristics in carbon metabolism,amino acid metabolism and fatty acid metabolism.These characteristics and corresponding verification experiments indicate their correlation with abnormal phenotypes,laying a research foundation for a better understanding of the occurrence of abnormal strains in L.edodes production.