Transgenic wheat with enhanced fungal resistance causes no effects on Folsomia candida (Collembola : Isotomidae)

摘要

The potential environmental impact of genetically modified (GM) plants is a major concern arising from the use of these novel crops. Therefore an ecological risk assessment should be done prior to the wide scale use of a GM crop. Soil microarthropods are a group of non-target organisms that should be considered as part of this risk assessment due to their importance for the decomposition process of organic matter and due to their intense exposure to crop residues in the soil. In the study described here, two different transgenic wheat varieties were used that express a gene from an Ustilago maydis-infecting virus. The gene product (KP4 protein) is known for its growth inhibitory activity against fungi in the Ustilaginales. These KP4-transgenic wheat plants show an enhanced resistance against stinking smut, Tilletia tritici. We describe different laboratory bioassays and a glasshouse study where we tested effects of the two transgenic KP4 wheat varieties on the Collembola Folsomia candida. Feeding bioassays in which dried root material from transgenic and non-transgenic wheat plants was fed to individual F candida revealed no effect of transformation or wheat variety on any of the life-history parameters evaluated. The comparison to an optimal food source (yeast) showed that certain parameters, i.e. insect development, egg cluster size and insect weight, are very sensitive parameters to detect differences in food quality. Other parameters including egg development and egg viability, revealed no difference between plant material and yeast fed F candida. The glasshouse study showed that population development of F candida did not differ between pots in which transgenic or non-transgenic plants of the two varieties were grown. However, a significant variety effect was detected.