Health & Environmental Research Online (HERO)


Print Feedback Export to File
2493536 
Journal Article 
Environmental, genomic and taxonomic perspectives on methanotrophic Verrucomicrobia 
Qiu, Q; Conrad, R; Lu, Y 
2009 
Yes 
Environmental Microbiology Reports
EISSN: 1758-2229 
WILEY 
HOBOKEN 
1 
5 
355-361 
English 
23765887 
WOS:000279517200009 
P>Most of methane in flooded rice fields is emitted via transport through the plant gas vascular system. In the reverse direction, oxygen is diffusing to the living roots, and hence, the rhizosphere and roots of rice serve as an important habitat for CH(4) oxidation which reduces CH(4) emission from flooded rice fields. A laboratory incubation experiment was performed to determine the activity and composition of the methanotrophic Proteobacteria inhabiting the rice root system. Excised root material from young- and old-nodal roots was collected and used for aerobic incubation in the presence of 13C-labelled CH(4). Prior to the incubation, the root material was treated with ammonium to test the effect of N availability on the activity of methanotrophs. Analyses of pmoA genes revealed that type II methanotrophs related to Methylocystaceae were predominant and remained relatively stable during the incubation regardless of root material and ammonium treatments. The abundance of type I methanotrophs was much smaller but their composition was relatively more variable. 16S rDNA-based stable isotope probing revealed that Sphingomonadales and methanotrophic Methylocystaceae were the most active bacteria assimilating CH(4)-derived carbon on young-nodal roots, whereas methylotrophic Methylophilales were active on old-nodal roots. These observations indicate the existence on rice roots of a bacterial food web that is driven by CH(4)-derived carbon.