Hard to digest or a piece of cake? Does GM wheat affect survival and reproduction of Enchytraeus albidus (Annelida: Enchytraeidae)?

In recent years a multitude of studies have been performed to evaluate potential risks of genetically modified (GM) plants on the environment. We investigated enchytraeids as we regard them as important model decomposer species, so far widely neglected in the context of GM plants risk assessments. Feeding experiments with transgenic and non-transgenic diets were conducted to check for possible effects on survival as well as reproduction of Enchytraeus albidus. We used GM wheat with either specific resistance against powdery mildew (Blumeria graminis) or unspecific resistance against fungi via chitinase and glucanase expression. Results indicate that effects due to specific resistance are either absent or too weak to affect number of surviving adults or number of offspring in a relevant way. Chitinase and glucanase expression affects the number of surviving adults negatively, however, a comparison of five conventional wheat varieties also revealed significant differences in the number of surviving adults. Since these differences were in the same range as the effect of glucanase and chitinase expression, it is questionable whether the negative transgenic effect is of ecological relevance or whether other biotic, abiotic and genetic factors are more important. Analysis of plant compound composition showed no differences between transgenic and non-transgenic wheat varieties, i.e. no correlation to number of surviving adults or number of offspring was observed for lignin, hemicellulose, and cellulose contents. (c) 2010 Elsevier B.V. All rights reserved.