| Title: | Defense of pyrethrum flowers: repelling herbivores and recruiting carnivores by producing aphid alarm pheromone |
| Author(s): | Li J; Hu H; Mao J; Yu L; Stoopen G; Wang M; Mumm R; de Ruijter NCA; Dicke M; Jongsma MA; Wang C; |
| Address: | "Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan, 430070, China. Business Unit Bioscience, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands. Wuhan Forestry and Fruit Tree Research Institute, Wuhan Academy of Agricultural Science and Technology, Wuhan, 430070, China. Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China. Laboratory of Cell Biology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands. Laboratory of Entomology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands" |
| ISSN/ISBN: | 1469-8137 (Electronic) 0028-646X (Print) 0028-646X (Linking) |
| Abstract: | "(E)-beta-Farnesene (EbetaF) is the predominant constituent of the alarm pheromone of most aphid pest species. Moreover, natural enemies of aphids use EbetaF to locate their aphid prey. Some plant species emit EbetaF, potentially as a defense against aphids, but field demonstrations are lacking. Here, we present field and laboratory studies of flower defense showing that ladybird beetles are predominantly attracted to young stage-2 pyrethrum flowers that emitted the highest and purest levels of EbetaF. By contrast, aphids were repelled by EbetaF emitted by S2 pyrethrum flowers. Although peach aphids can adapt to pyrethrum plants in the laboratory, aphids were not recorded in the field. Pyrethrum's (E)-beta-farnesene synthase (EbFS) gene is strongly expressed in inner cortex tissue surrounding the vascular system of the aphid-preferred flower receptacle and peduncle, leading to elongated cells filled with EbetaF. Aphids that probe these tissues during settlement encounter and ingest plant EbetaF, as evidenced by the release in honeydew. These EbetaF concentrations in honeydew induce aphid alarm responses, suggesting an extra layer of this defense. Collectively, our data elucidate a defensive mimicry in pyrethrum flowers: the developmentally regulated and tissue-specific EbetaF accumulation and emission both prevents attack by aphids and recruits aphid predators as bodyguards" |
| Keywords: | "Animals Aphids/*physiology Bicyclic Monoterpenes/metabolism Carnivory/*physiology Chrysanthemum cinerariifolium/drug effects/genetics/*physiology Coleoptera/physiology Flowers/drug effects/*physiology Gene Expression Regulation, Plant *Herbivory Pheromone;" |
| Notes: | "MedlineLi, Jinjin Hu, Hao Mao, Jing Yu, Lu Stoopen, Geert Wang, Manqun Mumm, Roland de Ruijter, Norbert C A Dicke, Marcel Jongsma, Maarten A Wang, Caiyun eng Research Support, Non-U.S. Gov't England 2019/05/16 New Phytol. 2019 Aug; 223(3):1607-1620. doi: 10.1111/nph.15869. Epub 2019 May 31" |
