2002 Fiscal Year Final Research Report Summary
Degradation of organically synthesized herbicides by the symbiosis of plants and endophytes.
| Project/Area Number |
13660070
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Plant nutrition/Soil science
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| Research Institution | Osaka Prefecture University |
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Principal Investigator |
OZAWA Takashi Osaka Prefecture University, Graduate School of Agriculture and Biological Sciences, 大学院・農学生命科学研究科, 助教授 (20152481)
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| Project Period (FY) |
2001 – 2002
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| Keywords | endophyte / bioremediation / symbiosis / herbicide / simazine / rhizosphere / environment remediation |
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| Research Abstract |
Simazine [2-chloro-4,6-bis(ethylamino)-s-triazine] is extensively used for the control of weeds, and has been detected as a pollutant in ground and surface water in Japan. Many kinds of microorganisms have been shown to degrade s-triazine herbicides. A majority of applications of these microorganisms to the contaminated soils, however, failed to promote the mineralization of the herbicides. It seems to be because of the difficulty for the inocula in persisting in soils and obtaining energy sources from the oligotrophic environments. This report presents that some of the endophytic bacteria isolated from com and soybean effectively degrade simazine in association with the host plants.
Tea may and Glycine max were grown on the soils which had been supplied with simazine at the rate of 2.6 g m^<-2> in the previous year. Four strains of Agrobacterium radiobacter and six strains of Bradyrhizobium japonicum were isolated from the surface-sterilized roots of com and soybean, respectively. These isolates grew in a basal liquid medium containing 0.2 mM simazine as a sole nitrogen source. More than 50% of simazine were consumed after 7 days of culture of these isolates. Inoculation of the simazine-degrading A. radiobacte strains to coms resulted in the rapid consumption of simazine in the soils. Soybean is much more sensitive to simazine than com. Formation of nodules by the simazine-degrading B. japonicum, however, increased resistance of soybeans against simazine. These results suggest a possibility of utilization of endophytes for remediation of herbicide-contaminated soils or production of simazine resistant cropping systems.
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