TABLE 1.

Numbers of 16S rRNA gene clones in clone libraries constructed from bulk soil and horseradish rhizosphere [¹³C]DNA obtained after 3, 7, and 14 days of incubation of the soils with [¹³C]biphenyl, as well as the number of unique OTUs (defined using 97% sequence identity) and the closest cultured relative(s) (according to Seqmatch at RDP-II) for each taxon

Taxon	No. of OTUs	Closest cultured relative(s) according to RDP Seqmatcha	No. of clones in library
			Bulk soil			Horseradish rhizosphere
			3 days	7 days	14 days	3 days	7 days	14 days
Paenibacillus	8	Paenibacillus validus (AF353697), Paenibacillus sp. strain Ao3 (EF208754)	44	3
Unclassified Phyllobacteriaceae	1	Phyllobacterium myrsinacearum (D12789)					1
Variovorax	1	Variovorax paradoxus (DQ256487)		1		2
Hydrogenophaga	9	Hydrogenophaga palleronii (AF019073)	4	31	26	45	37	23
Unclassified Burkholderiales	2	Leptothrix mobilis (X97071)						2
Achromobacter	2	Achromobacter xylosoxidans subsp. xylosoxidans (AJ491839)					7	2
Unclassified Alcaligenaceae	1	Alcaligenes sp. strain L6 (X92415)		3	1			1
Methylovorus	1	Methylobacillus flagellatus (CP000284)					2	1
Methylophilus	1	Methylophilus methylotrophus (AB193724)			1
Stenotrophomonas	1	Stenotrophomonas dokdonensis (DQ178977)			1
Unclassified Xanthomonadaceae	3	Pseudoxanthomonas spadix (AM418384)		10
Total	30		48	48	29	47	47	29

^aThe numbers in parentheses are accession numbers.