Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
Sci Rep. 2017 Jan 10;7:40509. doi: 10.1038/srep40509.
Diapause, also known as dormancy, is a state of arrested development that allows insects to survive unfavorable environmental conditions. Diapause-destined insects store large amounts of fat when preparing for diapause. However, the extent to which these accumulated fat reserves influence diapause remains unclear. To address this question, we investigated the function of fatty acid synthase (FAS), which plays a central role in lipid synthesis, in stress tolerance, the duration of diapause preparation, and whether insects enter diapause or not. In diapause-destined adult female cabbage beetles, Colaphellus bowringi, FAS2 was more highly expressed than FAS1 at the peak stage of diapause preparation. FAS2 knockdown suppressed lipid accumulation and subsequently affected stress tolerance genes expression and water content. However, silencing FAS2 had no significant effects on the duration of diapause preparation or the incidence of diapause. FAS2 transcription was suppressed by juvenile hormone (JH) and the JH receptor methoprene-tolerant (Met). These results suggest that the absence of JH-Met induces FAS2 expression, thereby promoting lipid storage in diapause-destined female beetles. These results demonstrate that fat reserves regulate stress tolerance genes expression and water content, but have no significant effect on the duration of diapause preparation or the incidence of diapause.
滞育，又称休眠，是一种发育停滞的状态，使昆虫能够在不利的环境条件下生存。准备进入滞育的昆虫在进入滞育前会储存大量的脂肪。然而，这些积累的脂肪储备对滞育的影响程度尚不清楚。为了解决这个问题，我们研究了脂肪酸合酶（FAS）的功能，它在脂质合成中起着核心作用，研究了它在应激耐受、滞育准备时间以及昆虫是否进入滞育或不进入滞育中的作用。在拟态滞育的成年雌性甘蓝叶甲（Colaphellus bowringi）中，在滞育准备高峰期，FAS2 的表达水平高于 FAS1。FAS2 的敲低抑制了脂肪积累，随后影响了应激耐受基因的表达和水分含量。然而，沉默 FAS2 对滞育准备时间或滞育发生率没有显著影响。FAS2 的转录受保幼激素（JH）和 JH 受体 methoprene-tolerant（Met）抑制。这些结果表明，JH-Met 的缺乏诱导了 FAS2 的表达，从而促进了拟态滞育雌性甲虫的脂肪储存。这些结果表明，脂肪储备调节应激耐受基因的表达和水分含量，但对滞育准备时间或滞育发生率没有显著影响。
