Presence of Cu-Type (NirK) and cd1-Type (NirS) Nitrite Reductase Genes in the Denitrifying Bacterium Bradyrhizobium nitroreducens sp. nov.

摘要

Nitrite reductase is a key enzyme for denitrification. There are two types of nitrite reductases: copper-containing NirK and cytochrome cd 1-containing NirS. Most denitrifiers possess either nirK or nirS , although a few strains been reported to possess both genes. We herein report the presence of nirK and nirS in the soil-denitrifying bacterium Bradyrhizobium sp. strain TSA1T. Both nirK and nirS were identified and actively transcribed under denitrification conditions. Based on physiological, chemotaxonomic, and genomic properties, strain TSA1T (=JCM 18858T=KCTC 62391T) represents a novel species within the genus Bradyrhizobium , for which we propose the name Bradyrhizobium nitroreducens sp. nov.