Physiological mechanisms by which gypsum increases the growth and yield of Lentinula edodes

Cultivation methods and biology of Lentinula edodes

In this study, the biological applications of cultivation methods related to cultivar selection, vegetative growth, and reproductive development in Lentinula edodes cultivation are briefly reviewed to clarify the current situation and inform future developments. The current cultivars widely used in the main production areas are derived from wild strains distributed in northern Asia. The most effective techniques for cultivar identification are molecular markers identified in two nuclear genome datasets and one mitochondrial genome dataset. The current stage of cultivar breeding is at the junction of Breeding 3.0 (biological breeding) and Breeding 4.0 (intelligent breeding). Plant breeder's rights and patents have different emphases on new breeding variety protection, with the former being the most utilized globally. L. edodes is mostly produced on synthetic logs filled with sawdust substrates. Hardwood sawdust comprises approximately 80% of the substrates. The vegetative growth of L. edodes on synthetic logs involves two distinct stages of mycelial colonization and browning. Mycelia mainly perform glycolysis, tricarboxylic acid cycle, and respiratory metabolism reactions to produce energy and intermediates for synthesizing the structural components of hyphae in the vegetative colonization stage. Upon stimulation by physiological and environmental pressures after colonization, mycelia trigger gluconeogenesis, autophagy, and secondary metabolism, increase metabolic flux of pentose phosphate pathway, activate the glyoxylate cycle, and accumulate melanin on the surface of logs to ensure growth and survival. Sexually competent mycelia can form hyphal knots as a result of reprogrammed hyphal branching patterns after a period of vegetative growth (which varies by cultivar) and stimulation by specific environmental factors. Under a genetically encoded developmental program, hyphal knots undergo aggregation, tissue differentiation, primordium formation, meiosis in the hymenium, stipe elongation, basidiospore production and maturation, and cap expansion to form mature fruiting bodies. Growers can achieve good fruiting body shape and high yield by regulating the number of young fruiting bodies and adjusting specific environmental factors. KEY POINTS: • Cultivar selection becomes less with the increasing technological requirement of L. edodes cultivation. • L. edodes mycelia showed different biological events in the mycelial colonization and browning stages. • Specific cultivar breading may be the next milestone in L. edodes cultivation.

Experimental Study on the Mechanism and Law of Low-Salinity Water Flooding for Enhanced Oil Recovery in Tight Sandstone Reservoirs

Currently, research surrounding low-salinity water flooding predominantly focuses on medium- to high-permeability sandstone reservoirs. Nevertheless, further investigation is necessary to implement this technique with regard to tight sandstone reservoirs. The present study comprises a series of experiments conducted on the crude oil and core of the Ordos Chang 6 reservoir to investigate the influence of ionic composition on low-salinity water flooding in tight oil reservoirs. The change in wettability on the rock surface was analyzed by using the contact angle experiment. The change in recovery rate was analyzed using a core displacement experiment. The reaction between rock fluids was analyzed using an ion chromatography experiment. Additionally, a nuclear magnetic resonance (NMR) experiment was used to analyze the mobilization law of crude oil and the change in wettability on the scale of the rock core. This led to a comprehensive discussion of the law and mechanism of enhancing the recovery rate via low-salinity water flooding from various perspectives. Experiments show that low-salinity water flooding is an effective technique for enhancing recovery in tight sandstone reservoirs. Altering the ionic composition of injected water can improve the water wettability of the rock surface and enhance recovery. Decreasing the mass concentration of Ca2+ or increasing the mass concentration of SO42- can prompt the ion-exchange reaction on the rock surface and detachment of polar components from the surface. Consequently, the wettability of the rock surface strengthens, augmenting the recovery process. Nuclear magnetic resonance experiments evidence that low-salinity water injection, with ion adjustment, significantly alters the interactions between the rock and fluid in tight sandstone reservoirs. As a result, the T2 signal amplitude decreases significantly, residual oil saturation reduces considerably, and the hydrophilic nature of the rock surface increases.

Hydrated lime promoted the polysaccharide content and affected the transcriptomes of Lentinula edodes during brown film formation

Brown film formation, a unique developmental stage in the life cycle of Lentinula edodes, is essential for the subsequent development of fruiting bodies in L. edodes cultivation. The pH of mushroom growth substrates are usually adjusted with hydrated lime, yet the effects of hydrated lime on cultivating L. edodes and the molecular mechanisms associated with the effects have not been studied systemically. We cultivated L. edodes on substrates supplemented with 0% (CK), 1% (T1), 3% (T2), and 5% (T3) hydrated lime (Ca (OH)2), and applied transcriptomics and qRT-PCR to study gene expression on the brown film formation stage. Hydrated lime increased polysaccharide contents in L. edodes, especially in T2, where the 5.3% polysaccharide content was approximately 1.5 times higher than in the CK. The addition of hydrated lime in the substrate promoted laccase, lignin peroxidase and manganese peroxidase activities, implying that hydrated lime improved the ability of L. edodes to decompose lignin and provide nutrition for its growth and development. Among the annotated 9,913 genes, compared to the control, 47 genes were up-regulated and 52 genes down-regulated in T1; 73 genes were up-regulated and 44 were down-regulated in T2; and 125 genes were up-regulated and 65 genes were down-regulated in T3. Differentially expressed genes (DEGs) were enriched in the amino acid metabolism, lipid metabolism and carbohydrate metabolism related pathways. The carbohydrate-active enzyme genes up-regulated in the hydrated lime treatments were mostly glycosyl hydrolase genes. The results will facilitate future optimization of L. edodes cultivation techniques and possibly shortening the production cycle.

Bioconversion of rice straw by Lentinula edodes under different spawn formulations

To attend to the growing world demand for mushrooms, it is interesting to increase the system's productivity, improve quality and reduce production costs. This study aimed to optimize the production and quality of fruiting bodies of the edible and medicinal mushroom Lentinula edodes (shiitake), in agroresidues substrate using appropriate strain and spawn formulation. The evaluation was conducted using two strains under seven different spawn formulations (Control [C]: Sorghum grain + 2.5% CaCO3; (2) C + 2.5% sawdust; (T3) C + 5% sawdust; (T4) C + 2.5% peat; (T5) C + 5% peat; (T6) C + 1.25% sawdust + 1.25% peat; (T7) C + 2.5% sawdust + 2.5% peat) that were inoculated into the blocks at a proportion of 2% (w/w). The substrate was formulated with 63% rice straw, 20% sawdust, 15% wheat bran, and 2% CaCO3 and sterilized. The incubation period was 87 days. Two flushes were obtained. Adding small aliquots of peat and sawdust to the inoculum gave significantly higher morphological results than the control in all variables analyzed. The days required for the first harvest ranged from 87 to 94 days. The average weight of basidiomes ranged from 6.38 to 28.75 g. The productivity data show superior results for the treatments in which the spawn was supplemented with sawdust and peat. Enhanced bioconversion with supplemented spawn shows promises for yield and composition improvement, crucial for commercial viability. It can be concluded that shiitake production using agroresidues such as straw can be increased using a suitable strain/spawn for optimal production.