Project description:Karst tiankengs are oases in degraded karst landscapes and act as repositories for biodiversity conservation; however, knowledge about the bacterial and fungal structure and function of the karst tiankeng ecosystems is limited. This study investigated the microbial communities in three different tiankeng (nondegraded, moderately degraded, and heavily degraded tiankeng) by Illumina NovaSeq sequencing. We found that the degradation of karst tiankeng can lead to changes in microbial community structure and functions, while there are differences in bacterial and fungal responses. There were significant differences in bacterial and fungal community composition and beta diversity in the three tiankeng soils. Random molecular ecological network analysis results indicated that a more complex and stable bacterial network existed in nondegraded tiankeng, while more complex fungal networks existed in moderately degraded tiankeng. The keystones of Proteobacteria, Actinobacteria, Acidobacteria, Ascomycota, and Basidiomycota played essential roles in maintaining soil function and stability. The functional profiles revealed that tiankeng habitat changes may affect microbial survival strategies, such as increasing gene abundance associated with the carbon cycle. To our knowledge, this is the first report on bacterial and fungal communities in different degrees of karst tiankeng, which provides crucial insights into our understanding of the microbial communities' structure and potential function in karst tiankeng ecosystems.
Project description:BackgroundKarst tiankengs serve as a reservoir of biodiversity in the degraded karst landscape areas. However, the microbial diversity of karst tiankengs is poorly understood. Here, we investigated the composition and function of the microbial community in a karst tiankeng.ResultsWe found that habitat differences inside and outside the karst tiankeng changed the composition and structure of the soil microbial communities, and the dominant phyla were Proteobacteria, Actinobacteria, Chloroflexi and Acidobacteria. The Shannon-Wiener diversity of microbial communities inside and outside the tiankeng was significantly different, and it was higher inside the tiankeng (IT). Venn and LEfSe analysis found that the soil microbial communities inside the tiankeng had 640 more endemic species and 39 more biomarker microbial clades than those identified outside of the tiankeng (OT)..Functional prediction indicated that soil microorganisms in outside the tiankeng had a high potential for carbohydrate metabolism, translation and amino acid metabolism. There were biomarker pathways associated with several of human diseases at both IT and OT sites. Except for auxiliary activities (AA), other CAZy classes had higher abundance at IT sites, which can readily convert litter and fix carbon and nitrogen, thereby supporting the development of underground forests. The differences in microbial communities were mainly related to the soil water content and soil total nitrogen.ConclusionsOur results provide a metagenomic overview of the karst tiankeng system and provide new insights into habitat conservation and biodiversity restoration in the area.