15 research outputs found
Desert Farming Benefits from Microbial Potential in Arid Soils and Promotes Diversity and Plant Health
BACKGROUND: To convert deserts into arable, green landscapes is a global vision, and desert farming is a strong growing area of agriculture world-wide. However, its effect on diversity of soil microbial communities, which are responsible for important ecosystem services like plant health, is still not known. METHODOLOGY/PRINCIPAL FINDINGS: We studied the impact of long-term agriculture on desert soil in one of the most prominent examples for organic desert farming in Sekem (Egypt). Using a polyphasic methodological approach to analyse microbial communities in soil as well as associated with cultivated plants, drastic effects caused by 30 years of agriculture were detected. Analysing bacterial fingerprints, we found statistically significant differences between agricultural and native desert soil of about 60%. A pyrosequencing-based analysis of the 16S rRNA gene regions showed higher diversity in agricultural than in desert soil (Shannon diversity indices: 11.21/7.90), and displayed structural differences. The proportion of Firmicutes in field soil was significantly higher (37%) than in the desert (11%). Bacillus and Paenibacillus play the key role: they represented 96% of the antagonists towards phytopathogens, and identical 16S rRNA sequences in the amplicon library and for isolates were detected. The proportion of antagonistic strains was doubled in field in comparison to desert soil (21.6%/12.4%); disease-suppressive bacteria were especially enriched in plant roots. On the opposite, several extremophilic bacterial groups, e.g., Acidimicrobium, Rubellimicrobium and Deinococcus-Thermus, disappeared from soil after agricultural use. The N-fixing Herbaspirillum group only occurred in desert soil. Soil bacterial communities were strongly driven by the a-biotic factors water supply and pH. CONCLUSIONS/SIGNIFICANCE: After long-term farming, a drastic shift in the bacterial communities in desert soil was observed. Bacterial communities in agricultural soil showed a higher diversity and a better ecosystem function for plant health but a loss of extremophilic bacteria. Interestingly, we detected that indigenous desert microorganisms promoted plant health in desert agro-ecosystems
Severe drought-induced community tolerance to heat wave. An experimental study on soil microbial processes
The effect of storage on microbial activity and bacterial community structure of drained and flooded paddy soil
Untangling the bacterial community composition and structure in selected Kuwait desert soils
Temporal dynamics of hot desert microbial communities reveal structural and functional responses to water input
The temporal dynamics of desert soil microbial communities are poorly understood. Given the
implications for ecosystem functioning under a global change scenario, a better understanding of
desert microbial community stability is crucial. Here, we sampled soils in the central Namib Desert
on sixteen different occasions over a one-year period. Using Illumina-based amplicon sequencing of
the 16S rRNA gene, we found that α-diversity (richness) was more variable at a given sampling date
(spatial variability) than over the course of one year (temporal variability). Community composition
remained essentially unchanged across the first 10 months, indicating that spatial sampling might be
more important than temporal sampling when assessing β-diversity patterns in desert soils. However,
a major shift in microbial community composition was found following a single precipitation event. This
shift in composition was associated with a rapid increase in CO2 respiration and productivity, supporting
the view that desert soil microbial communities respond rapidly to re-wetting and that this response
may be the result of both taxon-specific selection and changes in the availability or accessibility of
organic substrates. Recovery to quasi pre-disturbance community composition was achieved within one
month after rainfall.The National Research Foundation of South Africa (grant no.
81779 and TTK2008052000003), the Research Council of Norway (grant No. 180352) and the University of the
Western Cape. Partial support was also provided under the Laboratory Directed Research and Development Program at PNNL, a multiprogram national laboratory operated by Battelle for the U.S. Department of
Energy under contract DE-AC05-76RL01830.http://www.nature.com/scientificreportsam2016Genetic