| Budget Amount *help |
¥17,550,000 (Direct Cost: ¥13,500,000、Indirect Cost: ¥4,050,000)
Fiscal Year 2011: ¥5,330,000 (Direct Cost: ¥4,100,000、Indirect Cost: ¥1,230,000)
Fiscal Year 2010: ¥6,240,000 (Direct Cost: ¥4,800,000、Indirect Cost: ¥1,440,000)
Fiscal Year 2009: ¥5,980,000 (Direct Cost: ¥4,600,000、Indirect Cost: ¥1,380,000)
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| Research Abstract |
The role of bacteriophage(phage) communities in paddy soils was studied from the phage contribution to bio-element cycling in this study, and the frequency of phage infection to their hosts and the carbon flow of plant residue to phage DNA were evaluated. Fresh and dried^13C-labelled callus cells were used as the model materials of root cap cells and plant residue, respectively. The gene diversity and uniqueness of phage communities in soils were examined from the phage g23, g20 and psbA sequences in comparison with those in marine and freshwater environments. The frequency of virulent phage infection to bacteria in soils was markedly higher than those reported from marine and freshwater environments. The recovery of 13C-labelled g23 and g20 clones indicated that the phage communities are important in bio-element cycling as the drivers of the microbial loop. The diversity of g23 clones was significantly higher than those in marine and freshwater environments, and their sequences were mostly soil-specific and different from those of marine and freshwater origins. In addition, it was known that g20 and psbA gene sequences in the floodwater of paddy fields were more similar to the sequences in the freshwater environment than to those in the marine environments and that g20 sequences in paddy field soils were different from those not only of marine and freshwater origins but also in the floodwaters overlying.
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