Table S2 Bacterial strains used in this study to test the specificity of the nirK and nirS primers

Bacterial strains / nirK-517F/1055R / nirS-161F/878R / Source
Denitrifying strains with nirK
Ochrobactrum anthropi FZX-1 / ＋ / － / GIM
Paracoccus denitrificans ATCC 17741 / ＋ / － / ACCC
Bradyrhizobium japonicum ATCC15067 / ＋ / － / GIM
Mesorhizobium sp. BNC1 / ＋ / － / DSM
Rhizobium etli CFN 42 / ＋ / － / DSM
Rhizobium meliloti sp. / ＋ / － / IAE
Achromobacter cycloclastes ACCC03051 / ＋ / － / ACCC
Achromobacter xylosoxidans ATCC 15173 / ＋ / － / CGMCC
Herbaspirillum frisingense GSF 30 / ＋ / － / DSM
Herbaspirillum seropedicae Z78 / ＋ / － / DSM
Pseudomonas chlororaphis subsp. Aureofaciens DSM6698 / ＋ / － / DSM
Burkholderia thailandensis E264 / － / － / DSM
Azospirillum doebereinerae GSF 71 / － / － / DSM
Denitrifying strains with nirS
Ralstonia eutropha H16 / － / ＋ / DSM
Ralstonia eutropha CH34 / － / ＋ / DSM
Bordetella petrii DSM 12804 / － / ＋ / DSM
Thiobacillus denitrificans DSM12475 / － / ＋ / DSM
Herbaspirillum seropedicae Z67 / － / ＋ / DSM
Pseudomonas stutzeri A1501 / － / ＋ / CAAS
Pseudomonas aeruginosa ATCC9027 / － / ＋ / GIM
Marinobacter aquaeolei DSM11845 / － / ＋ / DSM
Azospirillum brasilense Sp7 / － / ＋ / DSM
Azospirillum lipoferum Sp59b / － / － / DSM
Azospirillum halopraeferens Au4 / － / － / DSM
Firmicutes, Gram+
Bacillus licheniformis ATCC 14580 (narG containing) / － / － / DSM
Bacillus cereus sp. (narG containing) / － / － / IAE
Corynebacterium glutamicum ATCC 13032 / － / － / DSM
Pseudonocardia sp. / － / － / IAE
Actinomadura sp. / － / － / IAE
Rhodococcus sp. / － / － / IAE

+, PCR product of the right size obtained; －, no PCR product obtained. Pseudomonas stutzeri A1501 were provided by prof. Min Lin, The Chinese Academy of Agricultural Sciences (CAAS).