Association of the components of soil microorganisms and the density of Schistosome-transmitting Oncomelania hupensis.

Soil microorganisms play an important role in the survival and development of soil-dwelling animals. Oncomelania hupensis, the sole intermediate host of Schistosoma japonicum, inhabitats in soil during its adult stage and is greatly influenced by the soil microenvironment. Nevertheless, the relationship between soil microorganisms and the density of O. hupensis remains poorly understood. In this study, we surveyed the density of O. hupensis and soil properties (physicochemical properties and microbial communities) in bottomlands from schistosomiasis endemic areas in the Dongting Lake and Poyang Lake regions, and the Anhui section of the Yangtze River in China. We employed 16S rRNA and ITS rRNA gene amplicon sequencing to characterize the bacterial and fungal communities in the soil, and examined the relationship between soil microbial communities and the density of O. hupensis. Our results showed that the density of O. hupensis was positively associated with the diversity of bacteria (ACE index (r = 0.749, p = 0.020), the Chao1 index (r = 0.750, p = 0.020) and the observed OTUs (r = 0.725, p = 0.027)) but negatively associated with the diversity of fungi (ACE index (r = -0.809, p = 0.008), the Chao1 index (r = -0.786, p = 0.012) and the observed OTUs (r = -0.674, p = 0.047)) as well as the relative abundance of seven bacteria phyla (Sva0485 (r = -0.696, p = 0.037), Spirochaetota(r = -0.714, p = 0.031), Nitrospirota (r = -0.731, p = 0.025), Desulfobacterota (r = -0.766, p = 0.016), Halobacterota (r = -0.836, p = 0.005), Chloroflexi (r = -0.836, p = 0.005) and Crenarchaeota) (r = -0.957, p < 0.001) and three fungi phyla (Entorrhizomycota (r = -0.698, p = 0.037), Basidiomycota (r = -0.818, p = 0.007) and Mucoromycota (r = -0.844, p = 0.004)). The complexity of the molecular network was positively correlated with the density of O. hupensis for bacteria (Nodes (r = 0.739, p = 0.023), Links (r = 0.737, p = 0.023) and Average degrees (r = 0.670, p = 0.049)), whereas, a negative relationship was observed for fungi (Nodes (r = -0.669, p = 0.049), Links (r = -0.668, p = 0.049) and Average degrees (r = -0.686, p = 0.042)). Further Partial Least Squares Path Model (PLSPM) analysis revealed that the diversity and network complexity of bacteria exerted a positive influence on the density of O. hupensis, whereas fungal diversity displayed a negative effect on the density of O. hupensis. In conclusion, soil microorganisms influence the density of O. hupensis, suggesting that modifying the soil microorganisms, such as reducing bacterial diversity or increasing fungal diversity, could serve as an eco-friendly strategy for O. hupensis management. Additionally, our study offered valuable guidance for the selection of molluscicidal microbes in subsequent research.