Function of Transcription Factors PoMYB12, PoMYB15, and PoMYB20 in Heat Stress and Growth of Pleurotus ostreatus.

MYB transcription factors (TFs) have been extensively studied in plant abiotic stress responses and growth and development. However, the role of MYB TFs in the heat stress response and growth and development of Pleurotus ostreatus remains unclear. To investigate the function of PoMYB12, PoMYB15, and PoMYB20 TFs in P. ostreatus, mutant strains of PoMYB12, PoMYB15, and PoMYB20 were generated using RNA interference (RNAi) and overexpression (OE) techniques. The results indicated that the mycelia of OE-PoMYB12, OE-PoMYB20, and RNAi-PoMYB15 mutant strains exhibited positive effects under heat stress at 32 °C, 36 °C, and 40 °C. Compared to wild-type strains, the OE-PoMYB12, OE-PoMYB20, and RNAi-PoMYB15 mutant strains promoted the growth and development of P. ostreatus. These mutant strains also facilitated the recovery of growth and development of P. ostreatus after 24 h of 36 °C heat stress. In conclusion, the expression of PoMYB12 and PoMYB20 supports the mycelium's response to heat stress and enhances the growth and development of P. ostreatus, whereas PoMYB15 produces the opposite effect.

Effects of different cooking methods on volatile flavor compounds, nutritional constituents, and antioxidant activities of Clitocybe squamulosa.

To explore a scientific and reasonable cooking method for Clitocybe squamulosa, four cooking methods (boiling, steaming, microwaving, and frying) were applied to C. squamulosa, and the effects of different cooking methods on volatile flavor compounds, nutritional constituents, and antioxidant activities in C. squamulosa were systematically investigated. The results showed that 54, 53, 61, 63, and 49 volatile flavor compounds were detected in raw, boiled, steamed, microwaved, and fried samples, respectively. Large differences in volatile flavor compounds between the four cooking and raw samples were determined by using relative odor activity values (ROAV) and principal component analysis (PCA). In addition, steaming and microwaving could protect the nutrients of C. squamulosa, reduce losses during the cooking process and improve the color of cooked products compared to boiling and frying cooking methods. Meanwhile, cooking treatment exerted different effects on the antioxidant activity of C. squamulosa, and the antioxidant activity of C. squamulosa was the highest after microwave cooking treatment. This research can provide a theoretical basis for the cooking, processing and utilization of C. squamulosa and other wild edible fungi.

Fast Positioning Model and Systematic Error Calibration of Chang'E-3 Obstacle Avoidance Lidar for Soft Landing.

Chang'E-3 is China's first soft landing mission on an extraterrestrial celestial body. The laser Three-Dimensional Imaging (TDI) sensor is one of the key payloads of the Chang'E-3 lander. Its main task is to provide accurate 3D lunar surface information of the target landing area in real time for the selection of safe landing sites. Here, a simplified positioning model was constructed, to meet the accuracy and processing timeline requirements of the TDI sensor of Chang'E-3. By analyzing the influence of TDI intrinsic parameters, a permanent outdoor calibration field based on flat plates was specially designed and constructed, and a robust solution of the geometric calibration adjustment was realized by introducing virtual observation equations for unknowns. The geometric calibration and its absolute and relative positioning accuracy verification were carried out using multi-measurement and multi-angle imaging data. The results show that the error of TDI intrinsic parameters will produce a false obstacle with a maximum height of about 1.4 m on the plane, which will cause the obstacle avoidance system of Chang'E-3 to fail to find a suitable landing area or find a false flat area. Furthermore, the intrinsic parameters of the TDI have good stability and the accuracy of the reconstructed three-dimensional surface can reach about 4 cm after error calibration, which provides a reliable terrain guarantee for the autonomous obstacle avoidance of the Chang'E-3 lander.

Transcription factor FfMYB15 regulates the expression of cellulase gene FfCEL6B during mycelial growth of Flammulina filiformis.

BACKGROUND: Cellulose degradation can determine mycelial growth rate and affect yield during the growth of Flammulina filiformis. The degradation of cellulose requires the joint action of a variety of cellulases, and some cellulase-related genes have been detected in mushrooms. However, little is known about the transcriptional regulatory mechanisms of cellulose degradation. RESULTS: In this study, FfMYB15 that may regulate the expression of cellulase gene FfCEL6B in F. filiformis was identified. RNA interference (RNAi) showed that FfCEL6B positively regulated mycelial growth. Gene expression analyses indicated that the expression patterns of FfCEL6B and FfMYB15 in mycelia cultured on the 0.9% cellulose medium for different times were similar with a correlation coefficient of 0.953. Subcellular localization and transcriptional activity analyses implied that FfMYB15 was located in the nucleus and was a transcriptional activator. Electrophoretic mobility shift assay (EMSA) and dual-luciferase assays demonstrated that FfMYB15 could bind and activate FfCEL6B promoter by recognizing MYB cis-acting element. CONCLUSIONS: This study indicated that FfCEL6B played an active role in mycelial growth of F. filiformis and was regulated by FfMYB15.

Mnsod1 promotes the development of Pleurotus ostreatus and enhances the tolerance of mycelia to heat stress.

BACKGROUND: Superoxide dismutases (SODs, EC 1.15.1.1) are defense proteins that can be used as sweepers to clear reactive oxygen species (ROS). They have been widely studied in the plant. Intensive research demonstrates that SOD plays an essential role in plants. However, in Pleurotus ostreatus, the function and regulatory pathway of SOD in the growth and development and the abiotic stress response have not been clear. RESULTS: In this study, three MnSOD-encoding genes of the P. ostreatus CCMSSC00389 strain were cloned and identified. Mnsod1, Mnsod2, and Mnsod3 were interrupted by 3, 7, and 2 introns, and encoded proteins of 204, 220, and 344 amino acids, respectively. By comparing the relative expression of three MnSOD-encoding genes in mycelia, the results showed that the gene with the highest primary expression was Mnsod1. Subsequently, the function of P. ostreatus Mnsod1 was explored by overexpression (OE) and RNA interference (RNAi). The results showed that during the growth and development of P. ostreatus, MnSOD1 protein increased gradually from mycelia to the fruiting body, but decreased in spores. The change of Mnsod1 transcription level was not consistent with the changing trend of MnSOD1 protein. Further studies showed that during primordia formation, the expression of Mnsod1 gradually increased, reaching a peak at 48 h, and the transcription level was 2.05-folds compared to control. H2O2 content progressively accumulated during the formation of primordia, and its change trend was similar to that of Mnsod1 transcription. OE-Mnsod1-1 and OE-Mnsod1-21 strains accelerated the formation of primordia. The results suggested that Mnsod1 may participate in the formation rate of P. ostreatus primordium by regulating the signal molecule H2O2. In addition, OE-Mnsod1-1 and OE-Mnsod1-21 strains shortened the mycelial recovery time after heat stress and improved the tolerance of the strains to 2.5 mM and 5 mM H2O2, which showed that Mnsod1 was involved in the response of P. ostreatus mycelium to heat stress. CONCLUSIONS: This study indicates that Mnsod1 plays an active role in the formation of P. ostreatus primordia and the response to abiotic stress.

Micromechanism Analysis of Surfactant Wetting of Coal Based on 13C NMR Experiments.

With the gradual improvement in coal mine mechanization and automation, the dust concentration at production sites is increasing significantly as the production efficiency improves, which not only poses a substantial threat to the occupational safety and health of workers but also affects the safe production and social stability of mines. At present, wet dust removal is the most economical and effective technical dust removal measure. However, most coal seams in China have poor wettability, unclear microscopic wetting mechanisms, and poor dust removal effects. Therefore, based on experiments and numerical analysis, this paper qualitatively studies the influencing factors of surfactants on coal wettability and quantitatively constructs an innovative evaluation model of the influence of the microstructure of coal and surfactants on wettability. First, based on 13C NMR experiments, the structural parameters of coal and several surfactants were obtained. Second, the wettability relationship between the coal and the surfactants was determined by optical titration, and the key factors affecting the wettability of coal dust and the wettability of the surfactants were selected. Then, using numerical analysis and function fitting analysis and combining the structural parameters with the coal wetting results, the relationship between the microstructure of the surfactants on different kinds of coal and the wettability of the coal samples was established. The results show that the ether group, the phenol or aromatic ether carbon, the fatty methyl group, and the aromatic methyl group in the surfactants have a substantial influence on the wettability. The research results can provide scientific guidance for the development of efficient and environmentally friendly compound dust suppressants to realize clean production in mines.

[Responses of shallow soil water content in Artemisia ordosica community to different rainfall patterns]. / æ²¹è’¿çŒä¸›ç¾¤è½æµ å±‚åœŸå£¤æ°´åˆ†å¯¹ä¸åŒé™é›¨æ ¼å±€çš„å“åº”.

The shrub species, Artemisia ordosica, commonly occurs in the eastern Hobq desert. Here, we used a micrometeorological observation system to continuously monitor the rainfall and soil water content in 0-10, 10-30, and 30-50 cm soil layers during the growing season from 2016 to 2018. The dynamic spatial and temporal changes in soil water content under different rainfall patterns were examined, and the replenishing effects of rainfall events on soil water content and water infiltration characteristics were analyzed. The results showed that soil water content of the surface layer in the A. ordosica community had significant seasonal and vertical variation under rainfall fluctuation. Rainfall amount and soil water content before rain were the main factors controlling soil water replenishment and infiltration. The soil surface layer (0-10 cm) was sensitive to rainfall, and the rainfall of 3.8 mm began to replenish this layer. The responses of 10-30 cm soil layer to rainfall was slower, more than 8.6 mm rainfall being needed for effective replenishment. The response of the 30-50 cm soil layer to rainfall was even more delayed, and replenishment at this depth could not be achieved until the rainfall exceeded 11.8 mm. The water infiltration rate increased with rainfall amount and decreased with soil depth, while water infiltration depth was positively correlated with the rainfall amount and soil water content before rainfall. During the study period, rainfall of <10 mm occurred predominantly, accounting for 78.4% of the total rainfall events. The rainfall mainly replenished soil layer above 30 cm, and the replenishment of deep soil was very limited, which was not conducive to the growth of deep-rooted species. Therefore, rainfall patterns directly affected the composition, distribution, and succession of plant communities in this area.

Desertification reversion alters soil greenhouse gas emissions in the eastern Hobq Desert, China.

Deserts cover more than 41% of the world's total land area and are significant in the terrestrial carbon cycle. The impact of desertification reversion and revegetation on the physical and chemical properties of soil is well studied; however, this study seeks to further the understanding of how they impact the flux of greenhouse gases (GHGs). Three sandy sites of different desertification reversal stages in the Hobq Desert were selected. Variations in the characteristics of GHG flux and its response mechanism to environmental hydrothermal conditions and soil properties were analyzed. Higher soil carbon dioxide (CO2) emissions were observed in the growing season, whereas nitrous oxide (N2O) emissions were mainly observed in the non-growing season. Methane (CH4) absorption showed no obvious seasonal change. Linear regression analysis revealed that GHGs in the study area were positively correlated with total nitrogen and organic carbon content, and the number of microorganisms present in the soil. Hydrothermal factors were critical controllers of soil CO2 emissions, but they did not majorly influence CH4 and N2O fluxes. The results illustrate the importance of desertification reversal and revegetation in mitigating climate change, and that deserts have a significant role in the global carbon cycle.

[Variations of soil respiration and its temperature sensitivity in the reversion process of desertification in the eastern Hobq Desert, China]. / åº“å¸ƒé½ä¸œç¼˜æ²™æ¼ åŒ–é€†è½¬è¿‡ç¨‹ä¸­åœŸå£¤å‘¼å¸åŠå ¶æ¸©åº¦æ•æ„Ÿæ€§å˜åŒ–.

To clarify the effects of desertification reversal on soil respiration rate (Rs) and its temperature sensitivity (Q10), five different reversal stages were selected: mobile dune, semi-fixed sandland, algae crust fixed sandland, lichen crust fixed sandland, and moss crust fixed sandland in the eastern Hobq Desert. Rs at different stages were measured by static chamber-gas chromatography and the Q10 was calculated. We analyzed the effects of environmental factors on Rs. The results showed that Rs gradually increased with sand fixation and vegetation succession: moss crust fixed sandland (0.78 µmol·m-2·s-1)> lichen crust fixed sandland (0.67 µmol·m-2·s-1)> algae crust fixed sandland (0.46 µmol·m-2·s-1)> semi-fixed sandland (0.42 µmol·m-2·s-1)> mobile dune (0.29 µmol·m-2·s-1). The Rs of growing season was higher than that of non-growing season. Q10 of Rs at different reversal stages followed the order: mobile dune (3.28)> semi-fixed sandland (2.93)> algae crust fixed sandland (2.54)> lichen crust fixed sandland (1.91)> moss crust fixed sandland (1.84). The Q10 of non-growing season was higher than that of growing season. There was positive correlation between Rs and soil temperature. Rs of mobile and semi-fixed sand was positively correlated with soil water content, but not in other three fixed sandlands. Rs was correlated with soil total nitrogen, organic carbon, bulk density, porosity, quantity of bacteria, quantity of actinomycetes and quantity of fungi. Our results indicated that in the process of desertification reversal, the increases of soil organic carbon and nitrogen content and the abundance of microbes, the improvement of soil texture and the accumulation of plant biomass could dramatically enhance soil respiration and reduce its temperature sensitivity, which were the main driving forces to change carbon cycle of desert soil, and mediate the effects of soil water on soil respiration.