| Co-Investigator(Kenkyū-buntansha) |
MOTOYAMA Takayuki RIKEN, Microbial Toxicology Laboratory, Researcher, 微生物制御研究室, 研究員 (70291094)
ARIE Tsutomu RIKEN, Mocrobiology Laboratory, Senior Research Scientist(1998-1999) ; Tokyo University of Agriculture and Technology, Faculty of Agriculture, Associate professor(2000), 農学部, 助教授 (00211706)
KUDO Toshiaki RIKEN, Mocrobiology Laboratory, Chief Scientist, 微生物学研究室, 主任研究員 (80109793)
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| Research Abstract |
1) Biodegradation of PCNB and its Derivatives in Soil by Plant-Microbe Symbiotic System
Rhizosphere microorganisms were subjected to screening for ability to degrade PCNB, a fungicide used to control clubroot disease of Brassica spp., and its derivatives. Pseudomonas gladioli M-2196, one of those microbes that metabolize PCNB to PCA, was a symbiont on the root of Allium spp. Mortierella sp. 15-4, a fungal symbiont on the root of Brassica spp., could degrade PCNB into PCTA.The M-2196-Allium spp. and 15-4-Brassica spp. symbiotic models showed effective degradation of PCNB in soil into PCA and PCTA, respectively. A gene(pcpB)encoding a PCP degrading enzyme was cloned from Sphingomonas chloropheolica and used to transform P.gladioli M-2196 and Fusarium sp. F4, both of which are plant symbionts. The transformed microbe-plant symbiotic systems could degrade PCP in soil effectively. We also found out the biocontrol ability in Phoma glomerara on clubroot and suggested that the effect was due to epoxydon produced by the fungus.
2) Accumulation of Metals by Plant from Soil using Plant-Microbe Symbiotic System
Several plant species showed different ability in accumulating metals from soil. Environmental factors, such as soil types and plant-symbiotic microbes gave effects on the accumulation, i. e., Fusarium sp. T3 increased the uptake of Cs and Sr by tomato.
3) Molecular-Evolutional Analysis on Symbiosis
Strategies for transformation of plant-symbiotic microbes were examined and symbiosis-deficient mutants were obtained by restriction enzyme mediated integration (REMI)method. A gene that might have a sole in symbiosis was identified from plant-symbiotic Fusarium sp. Futher, molecular analysis was performed on the evolution of plantsymbiotic microbes.
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