6533b7d7fe1ef96bd12680af

RESEARCH PRODUCT

DIAGSOL Development of a new functional marker for B-triketone herbicides exposure in agricultural soils

subject

description

International audience; The-triketone herbicides are maize selective herbicides that have been largely applied in replacement of atrazine, banned in Europe in 2004. Their mode of action lays on the inhi- bition of the p-hydroxyphenylpyruvate dioxygenase (HPPD), a key enzyme of the carotenoid biosynthesis.In recent studies, we showed that within the soil bacterial community, many microorganisms possess a functional HPPD enzyme involved in tyrosine metabolism. These ”non-target or- ganisms” harbor the target of the-triketone herbicides and consequently may be affected in response to its exposure. From this point of view, the bacterial community harboring the hppd gene might be a relevant marker to assess the ecotoxicological impact of _-triketone herbicides on soil bacterial functional diversity.Within this context, the objective of our work is to check for the interest of hppd bacterial community as a marker of exposition and/or of impact sensitive to _-triketone herbicides. This will require the development of a molecular tool box to assess the abundance, activity and diversity of the hppd bacterial community in various arable soils exposed to _-triketone herbicides. The abundance and the activity of the hppd bacterial community will be mon- itored from the nucleic acids extracted directly from soils, and the diversity of the hppd community will be evaluated by a metagenomic study based on the high-throughput se- quencing of hppd amplicons.Our results will lead to the selection of a set of characteristic hppd sequences, allowing the development of hppd DNA chips to assess the ecotoxicological impact of _-triketone herbicides on soil microorganisms.