Compound Microbial Agent Improves Soil Redox Status to Reduce Methane Emissions from Paddy Fields

Paddy fields are considered a major source of methane(CH_4)emissions.Aerobic irrigation methods have proven to be efficacious in mitigating CH_4 emissions in paddy cultivation.The promising role of compound microbial agents in refining the rhizospheric ecosystem suggests their potential as novel agents in reducing CH_4 emissions from paddy fields.To explore a new method of using compound microbial agents to reduce CH_4 emissions,we conducted pot and field experiments over the period of 2022-2023.We measured CH_4 flux,the redox potential(Eh)of the soil,the concentration of dissolved oxygen(DO)in the floodwater,and the gene abundance of both methanogens(mcr A)and methanotrophs(pmo A).The results showed that the application of the compound microbial agent led to a significant increase in the DO levels within the floodwater and an increase of 9.26%to 35.01%in the Eh of the tillage soil.Furthermore,the abundance of pmo A increased by 31.20%,while the mcr A/pmo A ratio decreased by 25.96%at the maximum tillering stage.Applying 45-75 kg/hm^(2) of the compound microbial agent before transplanting resulted in a reduction of cumulative CH_4 emissions from paddy fields by 17.49%in single-cropped rice and 43.54%to 50.27%in double-cropped late rice during the tillering stage.Correlation analysis indicated that CH_4 flux was significantly negatively correlated with pmo A gene abundance and soil Eh,and positively related to the mcr A/pmo A ratio.Additionally,soil Eh was significantly positively correlated with pmo A gene abundance,suggesting that paddy soil Eh indirectly affected CH_4 flux by influencing the pmo A gene abundance.In conclusion,the pre-planting application of the compound microbial agent at a rate of 45-75 kg/hm^(2) can enhance the Eh in the rhizosphere and increase the abundance of the pmo A gene,thereby reducing CH_4 emissions from paddy fields during the tillering stage of rice growth.

NMR identification of anti-influenza lead compound targeting at PA_C subunit of H5N1 polymerase

PA_C subunit from avian influenza（H5N1） viral RNA polymerase was used in this work as a target in the screening for anti-influenza agents from licorice-derived compounds.As a result,18β-glycyrrhetinic acid was suggested to be PA_C ligand by flexible docking,and was then confirmed by relaxation-edited NMR.The result of ApG primer extension assay indicated that this PA_C ligand can inhibit the polymerase activity,and thus may potentially be valuable as anti-influenza lead compound.This work validated the possibility of screening polymerase inhibitors by using PA_C as a target,and provided a starting point for the further discovery of new anti-influenza drugs.