Transgener Rapspollen in der Bienennahrung - Teil einer Modelluntersuchung zur Wahrscheinlichkeit des horizontalen Gentransfers von Pflanzen auf Bakterien

The potential of horizontal transfer of genes of pollen of herbicide-resistant rape (,pat' gene) to gut bacteria of bees has been studied in trial fields of the Federal Biological Research Centre for Agriculture and Forestry (BBA Kleinmachnow) since 2001. Transgenic rape is planted on an area of 1.200 m² (4 plots; each 300 m² ). As a part of a joint study with the Federal Research Centre for Agriculture (FAL Braunschweig), BBA Kleinmachnow determines the portion of transgenic rape pollen in bee food. To that end, three bee species have been established in the trial fields: honeybee (Apis mellifera L.), bumblebee (Bombus terrestris L.) and red mason bee (Osmia rufa L. syn. 0. bicornis L.). Samples were taken at three stages of tlowering, during early, füll and late flower. Depending on the stage of flowering, between 60 and 95% of pollen loads of A. mellifera originated almost totally from rape, but transgenic rape was found only in about 10% of samples. In B. terrestris, between 10 and 30% of samples consisted solely in rape, and another 10-20% contained rape-seed pollen at different proportions. Transgenic rape pollen was detected in between one and 30% of these samples. The mason bee was the only species where brood cells were studied, and here rape pollen was found in 60 to 80% of the cells. Between 50 and 60% of brood cells contained transgenic rape pollen. QC-PCR is being used with pat-positive samples to determine the proportion of transgenic rape pollen in corbicular pollen of individual bees and in individual brood cells.