cAMP-Mediated Biofilm eDNA Transfer Facilitates the Resilience of Soil Microbiome to Agrochemical Stress

Soil microorganisms utilize extracellular DNA (eDNA)-based biofilms as a defense against xenobiotics. However, the specific effects and transfer pathways of eDNA under persistent agrochemical exposure remain unclear. This study examined the transfer dynamics of carbofuran-hydrolase gene <i>pchA</i> from <i>Pseudomonas stutzeri</i> PS21. During biofilm formation, <i>pchA</i> was released from eDNA, leading to an enrichment of beneficial microorganisms such as <i>Acidobacteria</i> and <i>Elusimicrobia</i>, which enhanced organic compound metabolism and improved soil microbiome resilience. An increase in the <i>pchA</i>-associated mobile genetic elements and the colocalization of <i>pchA</i> with other bacterial species indicated the potential horizontal gene transfer (HGT) under carbofuran exposure. Additionally, carbofuran triggered a cAMP-dependent apoptotic pathway, leading to a 59.6% increase in <i>pchA</i> copy number, which suggested that cAMP played a role in initiating HGT. In conclusion, the cAMP-mediated interspecific transfer of <i>pchA</i> could enhance microbial coadaptation to carbofuran contamination, thereby strengthening the collective defense of soil microbiome against agrochemical stress.