Department of Entomology, College of Plant Protection, South China Agricultural University, Guangzhou 510640, China.
Department of Entomology, College of Plant Protection, South China Agricultural University, Guangzhou 510640, China.
Curr Biol. 2021 May 24;31(10):2220-2226.e4. doi: 10.1016/j.cub.2021.02.046. Epub 2021 Mar 18.
Volatile molecules produced by the microbiota play a primary role in chemical communication between insects, and direct production of pheromone components by the microbiota is one of the most obvious mechanisms. Here, we investigated the production of male-borne sex pheromones of the oriental fruit fly, Bactrocera dorsalis. As observed in previous studies, 2,3,5-trimethylpyrazine (TMP) and 2,3,5,6-tetramethylpyrazine (TTMP) are sex pheromones produced in the male rectum. Mature virgin females are strongly attracted to TMP and TTMP. 16S rRNA sequencing results show that the rectal bacteria are dominated by Bacilli that harbor the pathway to produce TMP and TTMP. The levels of Bacilli, TMP, and TTMP in the male rectum can be significantly decreased by feeding male flies with antibiotics. In vitro assays show that Bacillus species isolated from the male rectum can produce TMP and TTMP when provided with the substrates glucose and threonine, the levels of which are significantly higher in the rectum of mature males. These findings highlight the influence of microbial symbionts on insect pheromones and provide an example of direct bacterial production of pheromones in insects.
微生物产生的挥发性分子在昆虫的化学通讯中起着主要作用，而微生物直接产生信息素成分是最明显的机制之一。在这里，我们研究了东方果实蝇雄性携带的性信息素的产生。如先前的研究观察到的，2,3,5-三甲基吡嗪（TMP）和 2,3,5,6-四甲基吡嗪（TTMP）是在雄性直肠中产生的性信息素。成熟的处女雌性对 TMP 和 TTMP 有强烈的吸引力。16S rRNA 测序结果表明，直肠细菌主要由含有产生 TMP 和 TTMP 途径的芽孢杆菌主导。用抗生素喂养雄蝇可显著降低雄蝇直肠中的芽孢杆菌数量、TMP 和 TTMP 的水平。体外试验表明，从雄性直肠中分离出的芽孢杆菌在提供葡萄糖和苏氨酸等基质时可以产生 TMP 和 TTMP，而在成熟雄性的直肠中其水平明显更高。这些发现强调了微生物共生体对昆虫信息素的影响，并为昆虫中直接细菌产生信息素提供了一个实例。
