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Review article - Peer-reviewed, 2015

GM trees with increased resistance to herbivores: trait efficiency and their potential to promote tree growth

Hjältén, Joakim; Axelsson, Petter


Climate change, as well as a more intensive forestry, is expected to increase the risk of damage by pests and pathogens on trees, which already now can already be a severe problem in tree plantations. Intensified forestry to provide alternatives to fossil fuels and reduce our impact of CO2 into the atmosphere is also associated with an increased risk of damage by pests. Recent development of biotechnology theoretically allows for resistance enhancement that could help reduce these risks but we still we lack a comprehensive understanding of benefits and tradeoffs with pest resistant GM (genetically modified) trees. We synthesized the current knowledge on the effectiveness of GM forest trees with increased resistance to herbivores. There is ample evidence that induction of exogenous Bacillus thuringiensis genes reduce performance of target pests whereas upregulation of innateendogenous resistance traits e.g. phenolics, generates variable results. Our review identified very few studies estimating the realized benefits in tree growth of GM trees in the field. This is concerning as the realized benefit with insect resistant GM plants seems to be context-dependent and likely manifested only if herbivore pressure is sufficiently high. Future studies of secondary pest species and resistance evolution in pest to GM trees should be prioritized. But most importantly we need more long-term field tests to evaluate the benefits and risks cost with pest resistant GM trees.


GM trees, herbivore resistance, traits efficiency, tree growth, leaf damage

Published in

Frontiers in Plant Science
2015, Volume: 6, article number: 279
Publisher: Frontiers Media