1 Introduction
Crop damage caused by insects is a severe problem in agriculture. Moths (Lepidoptera) are major insect pests [1-3]. The European corn borer (ECB) Ostrinia nubilalis is the main pest of maize Zea mays in Europe [4]. It is estimated that in the absence of treatment, up to 20% of the crop may be lost due to the damage byO. nubilalis larvae [5]. Like other moth species, females ofO. nubilalis produce and release a fatty acid-derived sex pheromone, which attracts conspecific males for mating [6]. ECB is polymorphic with respect to its pheromone communication system and two pheromone races are recognized: the Z-race insects use a 97:3 blend of (Z )-11-tetradecenyl acetate (Z 11-14:OAc) to (E )-11-tetradecenyl acetate (E 11-14:OAc), while E-race insects use a 1:99 blend of the same components [6,7]. On maize in Europe, the Z-race is most prevalent [8].
Mating disruption has been proven an effective and environmentally friendly solution for crop protection against moths. For mating disruption, a more or less species-specific pheromone blend is applied to the fields or orchards to disrupt mating partner detection and, in this way, decrease the propagation of the pest species [9,10]. Currently, pheromones for pest management are produced synthetically from petrol-derived chemicals [11-13]. Chemical synthesis typically comprises multiple steps, uses toxic chemicals and solvents, and expensive catalysts. Biotechnological production of several insect pheromone components has already been established in plants and yeasts [14-18]. Oleaginous yeast Yarrowia lipolytica is particularly suitable for production of lepidopteran pheromones due to its naturally high level of fatty acid biosynthesis. Previously, we produced the precursor of the major pheromone component of Helicoverpa armigera (Z 11-16:OH) at 2.5 g/L in Y. lipolytica and proved the effectiveness of yeast-derived insect pheromone in field trapping experiments [16].
In this study, we aimed to produce Z 11-14:OAc, the major pheromone component of the ECB Z-race, using engineered Y. lipolytica as a host and demonstrate the activity of yeast-derived pheromone on O. nubilalis males.