The first crop plant genetically engineered to release an insect pheromone for defence

摘要

Insect pheromones offer potential for managing pests of crop plants. Volatility and instability areudproblems for deployment in agriculture but could be solved by expressing genes for the biosynthesisudof pheromones in the crop plants. This has now been achieved by genetically engineering a hexaploidudvariety of wheat to release (E)-β-farnesene (Eβf), the alarm pheromone for many pest aphids, using audsynthetic gene based on a sequence from peppermint with a plastid targeting amino acid sequence,udwith or without a gene for biosynthesis of the precursor farnesyl diphosphate. Pure Eβf was producedudin stably transformed wheat lines with no other detectable phenotype but requiring targeting ofudthe gene produced to the plastid. In laboratory behavioural assays, three species of cereal aphidsudwere repelled and foraging was increased for a parasitic natural enemy. Although these studies showudconsiderable potential for aphid control, field trials employing the single and double constructsudshowed no reduction in aphids or increase in parasitism. Insect numbers were low and climaticudconditions erratic suggesting the need for further trials or a closer imitation, in the plant, of alarmudpheromone release.