Exogenous Glucosinolate Produced by Transgenic Arabidopsis thaliana has an Impact on Microbes in the Rhizosphere and Plant Roots
Résumé
Genetic engineering of plant, through modification of natural defense system or artificial production of exogenous bioactive metabolites, has the potential to create new crops with increased resistance to pests and pathogens. However, potential detrimental effects of these modified plants on environment processes have to be measured. Here, we describe a study based on Bressan et al. (2009), in which the impact of the production of an exogenous glucosinolate by engineered Arabidopsis thaliana on associated microbial community was evaluated using a DNA‐stable isotope probe approach. This innovative technique, applied in the rhizosphere through plant culture under enriched 13C atmosphere, allows focusing on active microbial populations consuming root exudates. Bacterial (alphaproteobacteria, betaproteobacteria, gammaproteobacteria, and gammaproteobacteria), archaea, and fungal community structures were analyzed by polymerase chain reaction and denaturing gradient gel electrophoresis in root and rhizosphere compartments, considering 13C‐labeled and nonlabeled populations separately. The transgenic A. thaliana line caused significant alterations as compared to wild‐type plant in alphaproteobacteria, especially Rhizobiaceae, and fungal community structures and compositions, in both root and rhizosphere compartments. Surprisingly, only active 13C‐labeled populations of microbial community appeared to be influenced in the rhizosphere. Therefore, even a minor modification in transgenic plant could have repercussions on soil microbial communities and particularly on nontarget organisms. The use of engineered Brassicaceae crops has to be carried out with caution to avoid affecting important environmental functions bore by soil microorganisms.