Plant & Animal Genomes XV Conference Plant & Animal Genomes XV ConferenceJanuary 13-17, 2007
Town & Country Convention Center
San Diego, CA
Margaret Gruber , Limin Wu , Jennifer Holowachuk , Min Yu , Dwayne Hegedus , Juliana Soroka , Ning Xu , Andrew Sharpe
The tiny crucifer flea beetle (Phyllotreta cruciferae Goeze) has become the most devastating and dominant insect pest of North American Brassica napus canola fields and is a significant pest of Brassica vegetable crops. Adult flea beetles emerge in large numbers in the spring and feed on cotyledons and young leaves, quickly devastating a crop if left untreated. We have been unraveling the story of flea beetle - Brassica interactions to get snapshots of genes which should prove useful when developing resistant crops. In one strategy, we developed sets of insect-damaged and undamaged B. napus EST libraries, from which strongly-induced secondary metabolite genes, growth-related genes, and transcription factors were drawn. Their expression was profiled in developing tissues of B. napus under biotic and abiotic stress conditions; then the best candidates were tested for their ability to strengthen survival of Arabidopsis over-expression lines under flea beetle pressure and other stress conditions. Complementary strategies have focused on determining metabolite profiles and plant architecture that deter flea beetle feeding in wild crucifers and Arabidopsis. Through this work, we report several new traits, expression of B. napus genes in Arabidopsis, and "HAIRY CANOLA" with 1000-fold greater coverage of seedling trichomes. We also draw attention to newly-initiated projects in which trichome genes are being recovered from wild and domesticated Brassica species and trichome mutations from a new Arabidopsis activation-tagged population. The effect of these discoveries on host plant resistance will be presented. "Dinner is served; but the guests do not gather."