Soil aggregates, the basic structural unit of soil, provide special microhabitats and are assumed to protect both soil organic matter and microbiota against negative effects of harsh environmental conditions. Challenging to assess this protective effect on soil microbiota and soil DNA, we have calibrated in laboratory three different sizes of aggregates (0.5-1mm, 500-100µm and <100µm), obtained by dry sieving from 2 mm sieved fraction from a forest soil. In order to simulate extreme conditions, each fraction of aggregates was subjected to 1) Low Temperature Ashing (LTA) by oxygen plasma treatment and 2) high temperature by oven drying at 250°C, both at various time period of exposure (0, 5, 20 and 48 hours). Aggregate protection-effects on soil microbiota were evaluated in terms of microbial biomass (double strand DNA) and microbial community structure (Bacteria, Archaea and Fungi). To accurately assess the effect of oxidation and high temperature on soil DNA, we analytically discriminated between the extracellular (eDNA) and intracellular (iDNA) fraction of the soil metagenome, by sequential extraction and comparative genetic fingerprinting (Polymerase Chain Reaction and Denaturing Gradient Gel Electrophoresis) of eDNA and iDNA. The performed fine-tuning DNA analyses provided clear evidences about the protective effect of aggregates not only on the microbial cells of all domains (iDNA) but also on the soil extracellular DNA, this latter with important evolutionary implication (genetic exchange by natural transformation). Clear differences were observed between the type of treatment (oxidation, temperature), duration of treatment, and pore sizes. Microbiota was much more affected by high temperature than by oxidation (LTA), and the protection was negatively correlated with the duration of the treatment.

Soil aggregates: Protective hot spots for microbes under extreme environmental conditions / F. Borgogni F.; P. Arfaioli; J. Ascher; M.T. Ceccherini; L.P. D’Acqui; A. Bonetti; G. Pietramellara. - ELETTRONICO. - (2013), pp. 36-36. (Intervento presentato al convegno 2nd International Conference on Microbial Diversity-MD2013: Microbial Interactions in Complex Ecosystems. tenutosi a Turin, Italy nel 23-25 October 2013).

Soil aggregates: Protective hot spots for microbes under extreme environmental conditions.

BORGOGNI, FEDERICA;ARFAIOLI, PAOLA;ASCHER, JUDITH;CECCHERINI, MARIA TERESA;PIETRAMELLARA, GIACOMO
2013

Abstract

Soil aggregates, the basic structural unit of soil, provide special microhabitats and are assumed to protect both soil organic matter and microbiota against negative effects of harsh environmental conditions. Challenging to assess this protective effect on soil microbiota and soil DNA, we have calibrated in laboratory three different sizes of aggregates (0.5-1mm, 500-100µm and <100µm), obtained by dry sieving from 2 mm sieved fraction from a forest soil. In order to simulate extreme conditions, each fraction of aggregates was subjected to 1) Low Temperature Ashing (LTA) by oxygen plasma treatment and 2) high temperature by oven drying at 250°C, both at various time period of exposure (0, 5, 20 and 48 hours). Aggregate protection-effects on soil microbiota were evaluated in terms of microbial biomass (double strand DNA) and microbial community structure (Bacteria, Archaea and Fungi). To accurately assess the effect of oxidation and high temperature on soil DNA, we analytically discriminated between the extracellular (eDNA) and intracellular (iDNA) fraction of the soil metagenome, by sequential extraction and comparative genetic fingerprinting (Polymerase Chain Reaction and Denaturing Gradient Gel Electrophoresis) of eDNA and iDNA. The performed fine-tuning DNA analyses provided clear evidences about the protective effect of aggregates not only on the microbial cells of all domains (iDNA) but also on the soil extracellular DNA, this latter with important evolutionary implication (genetic exchange by natural transformation). Clear differences were observed between the type of treatment (oxidation, temperature), duration of treatment, and pore sizes. Microbiota was much more affected by high temperature than by oxidation (LTA), and the protection was negatively correlated with the duration of the treatment.
2013
Proceedings MD2013
2nd International Conference on Microbial Diversity-MD2013: Microbial Interactions in Complex Ecosystems.
Turin, Italy
F. Borgogni F.; P. Arfaioli; J. Ascher; M.T. Ceccherini; L.P. D’Acqui; A. Bonetti; G. Pietramellara
File in questo prodotto:
File Dimensione Formato  
Borgogni et al. 2013 MD13 extended abstract.doc

Accesso chiuso

Tipologia: Altro
Licenza: Tutti i diritti riservati
Dimensione 36 kB
Formato Microsoft Word
36 kB Microsoft Word   Richiedi una copia

I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/852310
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact