Resistance against beet armyworms and cotton aphids in caffeine-producing transgenic chrysanthemum

Abstract

Transgenic chrysanthemum plants were constructed to simultaneously express three N-methyltransferases involved in caffeine biosynthetic pathways. Resulting plants produced caffeine at approximately 3μgg -1 fresh tissue, and were tested for herbivore repellence. When starved second-instar caterpillars of beet armyworms (Spodoptera exigu) were allowed to feed, they ate up to 4.4mm2 of leaf discs from the wild type plants, while less than 1.5mm2 of those from the transgenic plants. When third-instars of cotton aphid (Aphis gossypii) were subjected to a choice-test, 27 gathered on wild type leaves, and 6 on transgenic leaves. These results indicate that caffeine-producing chrysanthemum is resistant against herbivores, lepidoptera caterpillars and aphids, both being one of the most serious pests in agriculture. We propose that the method can be practically applied to a variety of important plant species to confer resistance against biotic stresses. © 2011 The Japanese Society for Plant Cell and Molecular Biology.