banana monocultured soils

Continuous cropping of banana in the same field results in a serious soil-borne Fusarium wilt disease and a severe yield decline, a phenomenon known as soil sickness. While the soil microbial community plays a key role in the maintenance soil health, changes in its composition due to banana monoculture and the relationship to the disease incidence of soil sickness is still unclear. To address this, soil bacterial and fungal communities from banana fields with different monoculture spans were profiled by sequencing of the bacterial 16S rRNA and fungal internal transcribed spacer (ITS) genes using the MiSeq platformsequencing. Successive cropping of banana was found to be positively and negatively correlated with the Fusarium wilt disease incidence and crop yield, respectively. Bacterial and fungal community composition shifted in response to banana monoculture over different time frames with the fungal community exhibiting higher sensitivity. Bacterial and fungal diversity was positively and negatively correlated to banana Fusarium wilt disease incidence, respectively. The common banana fungal pathogenic genera Fusarium and Phyllosticta were closely associated with decreases in banana yield as well as increased disease incidence. Potential biocontrol agents were identified within Mortierella, Flavobacterium and Acidobacteria subgroups, who exhibited a significant correlation to disease suppression. In addition, both fungal and bacterial community compositions were highly impacted by the availability of soil organic matter. By utilizing network analysis, banana long-term monoculture was found to decrease the number of meta-modules, shift the composition of nodes from bacterial to fungal dominated and alter the majority of interactions from cooperation to competition. Overall, these findings indicate that long-term banana monoculture significantly impacts bacterial and fungal community composition and diversity, co-occurrence network architecture, Fusarium abundance and soil organic matter, ultimately resulting in increased wilt disease incidence.