CM	two-year consecutively monocultured soil
NP	newly planted soil (one-year cultured soil)
T-RFLP	terminal restriction fragment length polymorphism
PLFA	phospholipid fatty acid
ORF	open reading frame
KEGG	Kyoto Encyclopedia of Genes and Genomes
eggNOG	Evolutionary genealogy of genes: Non-supervised Orthologous Groups
KO	KEGG ortholog group
PCA	principal component analysis
PC1	the first principal component
PC2	the second principal component
UPGMA	unweighted pair-group method with arithmetic mean
SRA	Short Read Archive
nrGC	non-redundant gene catalogue
LCA	lowest common ancestor-based algorithm
COG	cluster of orthologous groups of proteins
FDR	false discovery rate