Ammonia-oxidizing archaea

important players in paddy rhizosphere soil?

Chen, Xue-Ping
Zhu, Yong-Guan
Xia, Yue
Shen, Ju-Pei
He, Ji-Zheng

Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.

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Received 29 January, 2008; accepted 20 February, 2008.

Environmental Microbiology 10(8):p 1978-1987, August 2008.

Summary

The diversity (richness and community composition) of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in paddy soil with different nitrogen (N) fertilizer amendments for 5 weeks were investigated using quantitative real-time polymerase chain reaction, denaturing gradient gel electrophoresis (DGGE) jand clone library analysis based on the ammonia monooxygenase α-subunit (amoA) gene. Ammonia-oxidizing archaea predominated among ammonia-oxidizing prokaryotes in the paddy soil, and the AOA:AOB DNA-targeted amoA gene ratios ranged from 1.2 to 69.3. Ammonia-oxidizing archaea were more abundant in the rhizosphere than in bulk soil. Rice cultivation led to greater abundance of AOA than AOB amoA gene copies and to differences in AOA and AOB community composition. These results show that AOA is dominant in the rhizosphere paddy soil in this study, and we assume that AOA were influenced more by exudation from rice root (e.g. oxygen, carbon dioxide) than AOB.