Fuente: Microorganisms - Revista científica (MDPI) Microorganisms, Vol. 14, Pages 595: DNA-Based Bacterial Community Profiles in Air-Dried Historical Soil Archives Are More Representative than Those from Rewetted Soils
Microorganisms doi: 10.3390/microorganisms14030595
Authors:
Peng Lu
Bingjie Ji
Yuan Yan
Shulan Zhang
Xueyun Yang

Recording and tracking the long-term dynamic changes in microbial populations is as essential as monitoring other soil properties for evaluating soil quality and health; however, this area has significantly lagged due to technical constraints and challenges in storing fresh soil samples. Historically archived soil samples offer a unique opportunity to characterize the temporal dynamics of microorganisms over several decades. To determine whether archived air-dried soils can be utilized for this purpose, we compared the structure and composition of bacterial communities across fresh soils, air-dried soil archives stored for varying durations, and their corresponding rewetted counterparts, all sourced from a long-term fertilization experiment on calcareous loess soil. Soil microbial features were characterized using the MiSeq sequencing platform. The results indicated that the similarity of DNA-based bacterial community composition between fresh soil and both archived and rewetted soils followed a downward quadratic curve as archiving time increased. Specifically, the DNA-based community structure of soils air-dried and preserved for one year, as well as those rewetted after eight years of archiving, remained highly similar to that of fresh soil. Regarding taxonomic shifts, the relative abundance of Actinobacteria in both air-dried and rewetted soils increased with storage time. Conversely, the relative abundances of Acidobacteria and Gemmatimonadetes significantly increased in air-dried soils but decreased upon rewetting over time. The relative abundances of Chloroflexi and Firmicutes remained stable in air-dried soils; however, after rewetting, the former decreased while the latter increased dramatically. Furthermore, Proteobacteria, Rokubacteria, Planctomycetes, Bacteroidetes, and Latescibacteria exhibited a decreasing trend in both air-dried and rewetted soils. These findings suggest that air-dried soils preserve DNA-based community profiles more effectively than rewetted soils, particularly for samples stored for less than eight years. This study provides a valuable reference for utilizing archived historical soil samples from long-term experiments to investigate microbial community evolution.