Hyperarid soil microbial community response to simulated rainfall

Frontiers in Microbiology

Microbiology

Roberto Véliz¹  Cecilia Demergasso¹  Cinthya Tebes-Cayo²  Albert Barberán³  Raina M. Maier³  Julia W. Neilson³  Guillermo Chong-Díaz⁴  Diego Ayma⁵  Daniel Laubitz⁵ 

[1] Biotechnology Center “Profesor Alberto Ruíz”, Universidad Católica del Norte, Antofagasta, Chile;Biotechnology Center “Profesor Alberto Ruíz”, Universidad Católica del Norte, Antofagasta, Chile;Department of Geology, Faculty of Engineering and Geological Sciences, Universidad Católica del Norte, Antofagasta, Chile;Department of Environmental Science, University of Arizona, Tucson, AZ, United States;Department of Geology, Faculty of Engineering and Geological Sciences, Universidad Católica del Norte, Antofagasta, Chile;Steele Steele Children’s Research Center, Department of Pediatrics, University of Arizona, Tucson, AZ, United States;

关键词: hyperarid;    soil microbiome;    soil wetting;    extremophiles;    oligotrophic microbes;    Atacama Desert;    mixotroph;   

DOI  :  10.3389/fmicb.2023.1202266

 received in 2023-04-07, accepted in 2023-07-31,  发布年份 2023

来源: Frontiers

【 摘 要 】

The exceptionally long and protracted aridity in the Atacama Desert (AD), Chile, provides an extreme, terrestrial ecosystem that is ideal for studying microbial community dynamics under hyperarid conditions. Our aim was to characterize the temporal response of hyperarid soil AD microbial communities to ex situ simulated rainfall (5% g water/g dry soil for 4 weeks) without nutrient amendment. We conducted replicated microcosm experiments with surface soils from two previously well-characterized AD hyperarid locations near Yungay at 1242 and 1609 masl (YUN1242 and YUN1609) with distinct microbial community compositions and average soil relative humidity levels of 21 and 17%, respectively. The bacterial and archaeal response to soil wetting was evaluated by 16S rRNA gene qPCR, and amplicon sequencing. Initial YUN1242 bacterial and archaeal 16S rRNA gene copy numbers were significantly higher than for YUN1609. Over the next 4 weeks, qPCR results showed significant increases in viable bacterial abundance, whereas archaeal abundance decreased. Both communities were dominated by 10 prokaryotic phyla (Actinobacteriota, Proteobacteria, Chloroflexota, Gemmatimonadota, Firmicutes, Bacteroidota, Planctomycetota, Nitrospirota, Cyanobacteriota, and Crenarchaeota) but there were significant site differences in the relative abundances of Gemmatimonadota and Chloroflexota, and specific actinobacterial orders. The response to simulated rainfall was distinct for the two communities. The actinobacterial taxa in the YUN1242 community showed rapid changes while the same taxa in the YUN1609 community remained relatively stable until day 30. Analysis of inferred function of the YUN1242 microbiome response implied an increase in the relative abundance of known spore-forming taxa with the capacity for mixotrophy at the expense of more oligotrophic taxa, whereas the YUN1609 community retained a stable profile of oligotrophic, facultative chemolithoautotrophic and mixotrophic taxa. These results indicate that bacterial communities in extreme hyperarid soils have the capacity for growth in response to simulated rainfall; however, historic variations in long-term hyperaridity exposure produce communities with distinct putative metabolic capacities.

【 授权许可】

Unknown   
Copyright © 2023 Demergasso, Neilson, Tebes-Cayo, Véliz, Ayma, Laubitz, Barberán, Chong-Díaz and Maier.