Justus-Liebig-University Giessen, Institute for Insect Biotechnology, Insect Biotechnology in Plant Protection, Winchesterstr. 2, 35394 Giessen, Germany; Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Winchesterstr. 2, 35394 Giessen, Germany.
Justus-Liebig-University Giessen, Institute for Insect Biotechnology, Insect Biotechnology in Plant Protection, Winchesterstr. 2, 35394 Giessen, Germany.
J Insect Physiol. 2020 Oct;126:104091. doi: 10.1016/j.jinsphys.2020.104091. Epub 2020 Aug 1.
The Spotted-wing Drosophila (Drosophila suzukii) is a devastating invasive pest of fruit crops. In D. melanogaster, the white (w) gene was associated with pigmentation and mating behavior, which are also important aspects to understand the invasion biology as well as to develop control strategies for D. suzukii. Here, we show that the generation of D. suzukii white-eyed mutants by CRISPR/Cas9 mutagenesis of the w gene resulted in the complete failure of copulation when w males were individually paired with w females in small circular arenas (diameter 0.7 cm) for 24 h. Further analysis showed that the mating defect was associated with w males and could not be rectified by two years of inbreeding by crossing sibling w females with w males, dim red illumination, male-female sexual training, changing to large arenas (diameter 3.5 cm), or different sex ratios. Profound pigmentation deficiency was detected in the compound eyes, ocelli, Malpighian tubules and testis sheaths in the w flies. Specifically, testis imaging showed that w males failed to deposit any pigments into pigment cells of the testis sheath, and produced smaller sperms and less seminal fluid compared to those from wildtype males. Together these observations suggest that the w gene plays an essential role in the regulation of sexual behavior and reproduction in D. suzukii. The similarities and differences in w gene function between D. suzukii and D. melanogaster in the context of pigmentation and mating behavior are discussed.
斑翅果蝇（Drosophila suzukii）是一种严重的入侵性水果作物害虫。在黑腹果蝇（Drosophila melanogaster）中，白色（w）基因与色素沉着和交配行为有关，这也是理解入侵生物学以及开发针对 D. suzukii 的控制策略的重要方面。在这里，我们通过 CRISPR/Cas9 对 w 基因进行诱变，生成了 D. suzukii 的白眼突变体，结果发现当 w 雄性个体在直径为 0.7 厘米的小圆形竞技场中与 w 雌性个体单独配对 24 小时时，交配完全失败。进一步的分析表明，交配缺陷与 w 雄性个体有关，并且通过两年的近亲繁殖（w 雌性个体与 w 雄性个体杂交）、弱红光照射、雌雄两性的性训练、将小竞技场改为直径 3.5 厘米的竞技场或改变雌雄比例都无法纠正这种缺陷。在 w 果蝇的复眼、小眼、马尔皮基氏管和睾丸鞘中都检测到了明显的色素缺乏。具体来说，睾丸成像显示 w 雄性个体未能将任何色素沉积到睾丸鞘的色素细胞中，与野生型雄性个体相比，w 雄性个体产生的精子更小，精液量也更少。这些观察结果表明，w 基因在 D. suzukii 的性行为和生殖调节中发挥着重要作用。本文还讨论了 w 基因在色素沉着和交配行为方面在 D. suzukii 和 D. melanogaster 之间的功能相似性和差异性。
