Transgenic chrysanthemum plants were constructed to simultaneously express three N-methyltransferases involved in caffeine biosynthetic pathways. Resulting plants produced caffeine at approximately 3 mg g Ϫ1 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 4.4 mm 2 of leaf discs from the wild type plants, while less than 1.5 mm 2 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.

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Aster yellows group phytoplasmas were reclassified by analysis of the 16S rRNA gene sequence, their phylogeny and the presence of interoperon heterogeneity. Nine phytoplasmas were classified into subgroups 16SrI-B and 16SrI-D using the 16S rRNA gene sequence. Then, based on the presence of interoperon heterogeneity, subgroup 16SrI-B phytoplasmas were differentiated into three subunits as 16SrI-B(a): mulberry dwarf, sumac witches' broom and porcelain vine witches' broom; 16SrI-B(b): angustata ash witches' broom and Japanese spurge yellows; and 16SrI-B(c): onion yellow dwarf, water dropwort witches' broom and hare's ear yellow dwarf phytoplasma.

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