Study On The Domestication Of Salt Alkali Tolerance Of Earthworms And Their Interaction With Soil Microorganisms Under Salt Alkali Stress

Earthworms,as low-cost early warning molluscs for monitoring soil quality,have strong remediation capabilities for soil,but their ecological importance is often overlooked.In recent years,research on various functional indicators of earthworms in polluted environments has been relatively increasing.Most of them have explored the changing process of microbial communities and microorganisms in earthworms from the perspectives of heavy metals,sludge,pesticide residues,pesticides,and other aspects.Through continuous gradient tests,they have explored the tolerance pathways and degradation capabilities of earthworms in different polluted environments.In this study,Eisenia foetida was used as the test earthworm species,and the initial earthworms were acclimated by simulating a highly saline and alkaline environment.The optimal acclimation conditions were excavated and selected(including time,salt alkali solution ratio,and substrate ratio scheme).In addition,the physiological and biochemical indicators of earthworms and the soil environment in which they live under high salt and alkali conditions were observed and measured,including the changes in the reproduction rate,lethality,newborn yield,peroxidase(POD),superoxide dismutase(SOD),glutathione peroxidase(GPX),malondialdehyde(MDA),and catalase(CAT)of salt-tolerant earthworms.At the same time,with the help of a macro genome sequencing database,data analysis was conducted on the diversity and function of microbial communities in saline and alkali tolerant earthworms and the soil environment,mining the strength and direction of the association between microbial diversity in vivo and in vitro of saline and alkali tolerant earthworms and related enzyme variables,and exploring the direct and indirect regulatory pathways between saline and alkali tolerant earthworms and the soil environment.The specific research results of this study are as follows:(1)Earthworms are more sensitive to high salt and alkali environments,and their related physical and chemical indicators tend to change significantly over time.When the p H of the soil environment is greater than 9.8,the mortality rate of earthworms is as high as 75% and above,and when the p H is greater than 6 and less than or equal to9,the mortality rate basically remains between 5% and 11%.(2)In the domestication stage of salt and alkali tolerant earthworms,the improved BP neural network prediction model was applied to the screening module for practical cultivation conditions of salt and alkali tolerant earthworms.Compared with ordinary practical operations,the average prediction accuracy of the three output neuron BP prediction models was 99.40%(>95%),and the linkage prediction relationship between the growth characteristics of salt-tolerant earthworms and environmental variables was explored.(3)In the analysis stage of dominant flora,the dominant species at the species level in the initial soil environment sample and the termination soil environment sample are mainly Steroidoactor＿Cummioxidans and Planctomymeters＿bacterium.The number of species with positive effects is higher than that with negative effects.At the same time,the abundance of intestinal samples from initial earthworms and salt tolerant earthworms is as high as 60% on Microbacterium and Nocardioides,and there are significant species differences at the level of Hyphomicrobium and Streptomyces.(4)At the stage of distribution and functional group analysis of intestinal microflora of saline-alkali tolerant earthworms,there are significant differences in the protein abundance of intestinal microorganisms in amino acid transport and metabolism(E)and energy production and conversion(C)between saline-alkali tolerant earthworms and initial earthworms.The significant genes involved in amino acid transport and metabolism in the intestinal samples of saline-alkali tolerant earthworms have a more significant upregulation process compared to the initial earthworm intestinal samples,The significance of the significantly upregulated genes involved in the lysine biosynthesis process is p<0.0001.Practical proof,it has been proved that earthworms can obtain relatively scarce amino acid resources in production activities.In particular,the gene encoding K00145(arg C,EC: 1.2.1.38),N-acetylglutamyl phosphate reductase,has fully completed the third step in arginine biosynthesis and its sub pathway ornithine biosynthesis.In addition,arg C can activate N-acetylcarbamate and produce 2-acetylamino-5-oxyvalerate,which plays an important leading and regulatory role in the aerobic metabolism process of earthworms.(5)In the interaction path analysis stage,the idea of combining principal component analysis and regression algorithms is applied to the interaction relationship exploration module,and the interaction function and structure between the microbial diversity in and out of saline-alkali tolerant earthworms and five enzyme variables,such as POD,SOD,CAT,MDA,and GPX,are mined through the method of biomathematical modeling.The results showed that,with the increase of time,the effect of five enzyme variables on microbial diversity in salt-alkali tolerant earthworms ranked in the following order: POD>SOD>GPX>CAT>MDA;The sequence of the effects of five enzyme variables on the microbial diversity of soil environmental samples at the end point is as follows: GPX>POD>CAT>SOD>MDA;In the correlation analysis of microbial diversity between saline tolerant earthworm samples and soil environmental samples,the order of action of the five enzyme variables was: GPX>POD>SOD>MDA>CAT.