[Effect of long-term fertilization on the diversity of nitrite reductase genes (nirK and nirS) in paddy soil].
In order to investigate the effects of long-term application of nitrogen fertilizer on soil denitrifying communities, the diversities of nir genes (nirK and nirS) were studied using molecular approaches in the long-term paddy field experiment (started in 1990) located in Taoyuan. Analysis of clone sequences indicated that the nirK fragments from paddy soil showed close similarity (90.7%) to the nirK sequences registered in GenBank database, but were not related to any known strain. Whereas, most of the airS clones showed low similarity (74.7%) to the nirS gene fragments registered in GenBank. The Chao1 estimates showed that the diversity of nirK gene 13) OTUs] than in N treatment [(49 +/- 9) OTUs], but the difference was not significant. However, application of nitrogen fertilizer resulted in significant difference of nirS-community compared to CK. Nitrogen fertilizer had obvious effect on tbe community structure of nirK-denitrifiers (p < 0.022), but the nirS-containing community was not affected. Based on phylogenetic analysis, nirK clones grouped into three clusters with aggregations of some OTUs cloned from N treatment. Although nirS clones grouped into four clusters, the majority of the clones were attributed in one cluster. The results suggested that application of nitrogen fertilizer had a greater influence on the diversity of nirS-containing bacterial community than that of the nirK. However, the community structure of nirK-containing denitrifiers was more sensitive to nitrogen fertilization than that of the mrS.
Luo
Xi-qian
XQ
Key Laboratory for Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China. ciciluoxixi@163.com
Chen
Zhe
Z
Hu
Rong-gui
RG
Wu
Min-na
MN
Qin
Hong-ling
HL
Wei
Wen-xue
WX
D001419:Bacteria / Q000145:classification / Q000201:enzymology / Q000235:genetics; D005308:Fertilizers; D014644:Genetic Variation / Q000187:drug effects*; D009572:Nitrite Reductases / Q000032:analysis / Q000235:genetics*; D009584:Nitrogen / Q000494:pharmacology*; D012275:Oryza / Q000254:growth & development*; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology; D013997:Time Factors
D005308:Fertilizers; D012987:Soil; D009572:Nitrite Reductases; C052695:nitrite reductase, copper-containing; D009584:Nitrogen