title: Differentiated response of denitrifying communities to fertilization regime in paddy soil.
abstract: The impact of fertilization regimes on sequential denitrifying communities was investigated in a rice paddy field with 17 years continuous fertilization, located in Taoyuan Agro-ecosystem Research Station (110°72″ E, 28°52″ N), China. The diversity, community composition, and size of denitrifying genes of narG, qnorB, and nosZ were determined using molecular tools including terminal restriction fragment length polymorphism, quantitative polymerase chain reaction (qPCR), cloning, and sequencing analysis. Soil samples were collected from the plots with no fertilizer (NF), urea (UR), balanced mineral fertilizers (BM), and BM combined with rice straw (BMR). UR and BM caused marked increase in the community size of the denitrifying genes; however, BMR resulted in the highest abundance. The community size of narG was the most affected by the fertilization regimes, while qnorB was the least. Fertilization also induced some shifts in the composition of denitrifying genes, but the responses of different genes varied. However, fertilization regimes caused no significant changes to the diversity of the denitrifying genes. Potential denitrification activity (PDA) was significantly correlated with the abundance of narG and nosZ rather than qnorB, but there were no such correlations between PDA and the composition and diversity of denitrifying communities. Conclusively, long-term fertilization significantly affected denitrifying community size and composition, but not diversity. Among the sequential denitrifying genes, narG was the most, while qnorB was the least sensitive communities to fertilization regimes.
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Regions and Taoyuan Agro-ecosystem Research Station, Soil Molecular Ecology Section, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Chen
authors.forename: Jinbo
authors.initials: J
authors.lastname: Liu
authors.forename: Minna
authors.initials: M
authors.lastname: Wu
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Xie
authors.forename: Jinshui
authors.initials: J
authors.lastname: Wu
authors.forename: Wenxue
authors.initials: W
authors.lastname: Wei
mesh_terms: D001419:Bacteria / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*; D001426:Bacterial Proteins / Q000235:genetics*; D002681:China; D058440:Denitrification; D005308:Fertilizers / Q000032:analysis; D018628:Gene Dosage; D008969:Molecular Sequence Data; D009572:Nitrite Reductases / Q000235:genetics*; D012275:Oryza; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D060888:Real-Time Polymerase Chain Reaction; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology
chemical_list: D001426:Bacterial Proteins; D005308:Fertilizers; D012987:Soil; D009572:Nitrite Reductases