Impacts of organic soil amendment on bacterial-fungal interactions

We aimed to investigate microbial dynamics in soil treated with stabilised spent mushroom substrate (SMS), a soil amendment rich in nutrients and complex organic matter. A 14 week soil trial assessed the plant growth promoting properties of the SMS and microbial successional processes were monitored and compared with a mineral treatment. Prokaryotic (16S rRNA) and fungal (ITS) communities were analysed by high-throughput amplicon sequencing at both DNA and RNA (cDNA) levels. Using a combination of computational tools, we assessed the persistence of SMS-derived taxa in soil, and the changes in co-occurrence patterns and microbial community structure over time. Soil prokaryotic communities displayed higher levels of resilience to the changes introduced by SMS treatment while the SMS fungal community successfully colonised the soil, during the time monitored. The presence of highly connected microbial guilds . was observed and were composed of fungal and bacterial taxa with reported complex organic matter degradation abilities. Many of these taxa were also significantly correlated with organic matter content and plant yield, suggesting that these highly connected taxa may play key roles not only in the community structure, but also in the plant-soil feedback under organic fertilisation