Function prediction and network analysis to investigate the response of microbial communities to a single environmental factor

Abstract

As an important factor affecting the structure of microbial communities, salinity has traditionally been a focus of exploratory studies of microorganisms. Here, we defined a salinity gradient with reference to the degree of natural salinization in a lake and withdrew the influence of irrelevant factors to explore the impacts of changes in salinity on the biological community. With the gradual increase in salinity, we found that Firmicutes replaced Bacteroidetes as the dominant flora. Through a network diagram, we found that Bacteroidetes had a weaker taxonomic correlation with the bacterial community in the saline environment, which indicated that the increase of salinity did play a role in filtering the bacterial community. In addition, we also found the typical freshwater bacteria GKS98 in a higher salinity environment, which supports the idea proposed by previous researchers that salinity creates a wider niche. However, our functional prediction results show that salinity is not the main factor affecting the functional characteristics of bacterial communities. Moreover, through a network diagram, we found that the symbiotic relationship between GKS98 and other strains also changed with increasing salinity. This suggests that the effects of salinity on microorganisms may involve additional ecological mechanisms such as niche occupation and functional interdependence within the community.

Keywords

• 454 high-throughput sequencing
• bacterial community composition
• environmental factors
• co-occurrence network
• functional genus