2.10. Assay of the number of total soil microbes
Total numbers of bacteria and fungi were quantified by realtime PCR. Bacteria and fungi numbers were quantified following
the method described by Fierer et al. (2005)[29]. To estimate the
small-subunit rRNA gene abundances of bacteria and fungi, standard curves were generated using 10-fold serial dilutions of a
plasmid containing a full-length copy of the 16S rRNA gene from
Escherichia colior the 18S rRNA gene fromSaccharomyces cerevisiae.
Standard and environmental DNA samples were analyzed on a
7500 Real Time PCR System (Applied Biosystem, USA) according to
a standard procedure. Each sample was performed in three replicates, and the results were expressed as log (copy numbers g
1
dry
soil)