Table 2. Quality-control information, sequence length-distribution and OTU clustering.

Sample	Raw reads	Clean reads	Base (nt)	Avg. Length (nt)	Q20	Effective (%)	OTUs	Unique OTUs
KK1	112427	90158	38683375	429	90.59	80.19	200	30
KK2	95143	90373	38612344	427	89.13	94.99	354	116
KK3	93567	90319	38764167	429	87.82	96.53	204	29
RE	78982	75132	32301400	429	82.68	95.13	235	81
KS	100129	90111	38130981	423	86.47	89.99	239	46

Raw reads means reads after filtration; Clean reads means reads after removal of chimeras; Base means base number of nucleotides in clean reads; Avg. Length means average length of clean reads; Q20 means the percentage of bases of quality greater than 20; Effective (%) means the percentage of clean reads relative to raw reads; OTUs means the number of OTUs identified in different samples; Unique OTUs means the number of OTUs only identified in a single sample.