Mechanism Of Synergistic Resistance Of Soil Indigenous Flora And Earthworm Intestinal Flora To Organochlorine Pesticide Toxicity

Earthworm intestinal flora are involved in various biochemical processes of soil environment and interacts closely with indigenous flora to maintain the internal stability of soil.It has not clear how the interaction between earthworm intestinal flora and indigenous flora will be affected when the soil environment is disturbed(such as the input of pesticide pollution).The interaction mode of these two specific groups in the process of resistance to adverse environment and the relationship between them and soil homeostasis are worth further study.In this study,the structure and function of earthworm intestinal flora and indigenous flora were analyzed using high-throughput sequencing technology and acer sequencing technology in soil samples from typical pesticidcontaminated sites in the Yangtze River Delta region of China.Through statistical analysis and network analysis,the core taxa were identified.The main results and conclusions were as follows: 1)There were close species and gene transfer processes between earthworm intestinal flora and indigenous flora under different pesticide stress;2)There was a stable core population of earthworm intestinal flora and indigenous flora under different levels of chlordane pesticide stress,which mainly consisted of Flavobacteria,Ammooxidized Archaea and Acinetobacter,etc.,and these core populations had the ability of carbon and nitrogen conversion and pesticide degradation;3)The increase of pesticide concentration reduced the interaction tightness between the indigenous flora and the intestinal flora of earthworm,and made the co-occurrence network mean degree centrality,closeness centrality and eigenvector centrality decrease from 443.36,0.89 and0.92 to 378.78,0.84 and 0.87,which caused the blocking of the species and gene communication path between the flora.4)Toxicity sharing model showed that the pesticide poisoning sharing coefficient of the key genes in earthworm gut(103.0%-130.2%)> pesticide poisoning sharing coefficient of general genes(97.4%-125.7%)>pesticide poisoning sharing coefficient of species(79.2%-85.1%),revealed that earthworm intestinal flora can share pesticide toxicity through gene regulation,especially by regulating carbon and nitrogen metabolism and pesticide degradation genes,and cooperate with indigenous flora to resist organochlorine pesticide stress.The results of this study could provide a new scientific understanding of the contribution mechanism of indigenous flora and earthworm intestinal flora to the resistance to organochlorine pesticide stress in soil and the joint maintenance of soil microbial homeostasis.