The wide range of feeding types and the ability to adapt to seasonal succession make nematodes significant indicators of ecological conditions of the soil in which they occur. Soil nematophauna is highly sensitive to any environmental damage and, therefore, the analysis of soil nematode community can be a useful diagnostic tool of soil health changes caused by polluting agents, among which also pesticides. Traditional morpho-taxonomic techniques for analysis of soil nematophauna have been flanked or substituted by more innovative and quicker molecular tools. Effectiveness of morpho-taxonomic and molecular techniques was comparatively evaluated through the analysis of soil nematode community from three selected relatively undisturbed and disturbed sites in Apulia region (Italy). Nematodes for both analyses were extracted from 100g sub-samples of composite soil samples collected at each site. Specimens for morphological analysis were fixed in a 2.5% formaldehyde solution and then identified at family and genus level under an optical microscope. The maturity and trophic diversity indices were determined. Total DNA was extracted from the nematode community of each soil subsample and PCR amplification was performed by using the small subunit (18s) of the ribosomal DNA gene, as diagnostic marker. The 18s rDNA was selected because of the large number of 18s sequences in GenBank, the existence of an 18s-based phylogenetic tree and the conserved nature of this gene to ensure complete phylogenetic coverage of the phylum. Sequence analysis through BLAST allowed to classify most of them at genus level and some of them at species level. Few sequences showed no similarity with those present in the database suggesting that they are new for the scientific community. The maturityand trophic diversity indices were also calculated for genera identified at molecular level. Results confirmed that nematodes are good indicators of soil health, as showing a different level of disturbance for each of the three sampled sites. Both morpho-taxonomic and molecular tecniques showed to be effective, though morpho-taxonomic is more time-consuming and skilfulness-requiring whereas a molecular analysis is largely more expensive.
Analysis of soil nematophauna diversity as indicator of pesticides risk
Troccoli A;Fanelli E;D'Addabbo T;Veronico P;Radicci V;De Luca F
2013
Abstract
The wide range of feeding types and the ability to adapt to seasonal succession make nematodes significant indicators of ecological conditions of the soil in which they occur. Soil nematophauna is highly sensitive to any environmental damage and, therefore, the analysis of soil nematode community can be a useful diagnostic tool of soil health changes caused by polluting agents, among which also pesticides. Traditional morpho-taxonomic techniques for analysis of soil nematophauna have been flanked or substituted by more innovative and quicker molecular tools. Effectiveness of morpho-taxonomic and molecular techniques was comparatively evaluated through the analysis of soil nematode community from three selected relatively undisturbed and disturbed sites in Apulia region (Italy). Nematodes for both analyses were extracted from 100g sub-samples of composite soil samples collected at each site. Specimens for morphological analysis were fixed in a 2.5% formaldehyde solution and then identified at family and genus level under an optical microscope. The maturity and trophic diversity indices were determined. Total DNA was extracted from the nematode community of each soil subsample and PCR amplification was performed by using the small subunit (18s) of the ribosomal DNA gene, as diagnostic marker. The 18s rDNA was selected because of the large number of 18s sequences in GenBank, the existence of an 18s-based phylogenetic tree and the conserved nature of this gene to ensure complete phylogenetic coverage of the phylum. Sequence analysis through BLAST allowed to classify most of them at genus level and some of them at species level. Few sequences showed no similarity with those present in the database suggesting that they are new for the scientific community. The maturityand trophic diversity indices were also calculated for genera identified at molecular level. Results confirmed that nematodes are good indicators of soil health, as showing a different level of disturbance for each of the three sampled sites. Both morpho-taxonomic and molecular tecniques showed to be effective, though morpho-taxonomic is more time-consuming and skilfulness-requiring whereas a molecular analysis is largely more expensive.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
