The Desaturase Gene Regulates the Performance of the Brown Planthopper and Its Relationship with Rice.

Insect desaturases are known to play an important role in chemical communication between individuals. However, their roles in insect growth, development and fecundity, and in regulating interactions of insects with plants, remain largely unknown. In this study, we explored the functions of , a desaturase gene of the brown planthopper (BPH), (Stål). The RNA interference-based knockdown of decreased the ratio of monounsaturated fatty acids to saturated fatty acids, and the level of fatty acids and triglycerides in BPH. -knockdown also reduced the food intake, body mass and fecundity of female BPH adults, and led to abdomen atrophy and ovarian agenesis. -knockdown suppressed the transcription of (target of rapamycin), (Lipophorin) and (adipokinetic hormone receptor) in female adults. Moreover, the corrected survival rate of BPH with -knockdown fed an artificial diet was higher than the survival rate of those fed on rice plants. Higher levels of salicylic acid in rice infested by -knockdown female BPH adults than in rice infested by control BPH may be the reason. These findings demonstrate that has an essential role in lipid metabolism and is involved in the food intake, survival, development and fecundity of BPH. In addition, this gene is likely involved in regulating the responses of rice to BPH infestation.