Liuyang Wang,Pei Guo,Xiaofang Zhang,Yun Duan,Jun Ning,Tao Zhang,Xinling Yang
In moths, sex pheromones are synthesized in pheromone glands (PGs) by a variety of enzymes. Desaturases (DESs) are critical for the introduction of double bonds into pheromones. In Mythimna loreyi, the specific DESs involved in sex pheromone biosynthesis remain unclear. In this study, we identified and characterized 25 putative DESs from the M. loreyi genome. Nineteen of them were expressed in the female PGs, with seven showing significant upregulation in response to pheromone biosynthesis activating neuropeptide (PBAN). RNAi-based knockdown of MlorDES2 significantly reduced the titer of pheromone components by 58.6–85.9%, while knockdown of MlorDES9 specifically reduced the production of (Z)-9-tetradecenyl acetate. Functional verification in yeast revealed that MlorDES2 and MlorDES9 exhibited Δ11 and Δ9 desaturase activities, respectively. Taken together, these results collectively demonstrate that MlorDES2 and MlorDES9 are involved in sex pheromone biosynthesis of M. loreyi, suggesting that DESs could be used as potential targets for pest management.
Sex pheromones, which play a critical role in mediating sexual communication of Lepidoptera, are biosynthesized by a variety of particular enzymes in specialized pheromone glands (PGs). Among these enzymes, fatty acyl-CoA reductases (FARs) catalyze the reduction of fatty acyl precursors to their corresponding alcohols. In this study, we identified 32 FARs from the genome of Mythimna loreyi, an important agricultural pest. Among all MlorFARs identified, only MlorFAR1 showed a PG expression pattern and exhibited a positive response to pheromone biosynthesis activating neuropeptide (PBAN) injection. Silencing MlorFAR1 reduced pheromone titers by 70.4–88.9% and significantly reduced mating rates at the 48–72 h postinjection time point. Heterologous expression in yeast confirmed that MlorFAR1 preferentially converted medium-chain fatty acid methyl esters to alcohols. These findings establish MlorFAR1 as a pivotal enzyme in the biosynthesis of sex pheromones in M. loreyi, providing a framework for the development of innovative pest management strategies.
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