State Key Laboratory for Biology of Plant Diseases and Insect Pests, Key Laboratory of Natural Enemy Insects, Ministry of Agriculture and Rural Affairs, Key Laboratory of Integrated Pest Management in Crops, Ministry of Agriculture and Rural Affairs, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
Pest Manag Sci. 2024 Jul;80(7):3665-3674. doi: 10.1002/ps.8070. Epub 2024 Apr 3.
The ladybeetle, Coccinella septempunctata, an important predator, is widely used to control aphids, whiteflies, mites, thrips, and lepidopteran pests. Diapause control technology is key to extending C. septempunctata shelf-life and commercialization. Lipid accumulation is a major feature of reproductive diapause, but the function of AKH signaling as a regulator of lipid mobilization in reproductive diapause remains unclear. This study aimed to identify and characterize AKH and AKHR genes, and clarify their functions in reproductive diapause.
The relative expression levels of CsAKH and CsAKHR were the highest in the head and fat body, respectively, and were significantly decreased under diapause conditions, both in developmental stages and tissues (head, midgut, fat body, and ovary). Furthermore, CsAKH and CsAKHR expression was increased significantly after juvenile hormone (JH) injection, but CsMet silencing significantly inhibited CsAKH and CsAKHR expression, whereas CsMet knockdown blocked the induction effect of JH. CsAKH and CsAKHR knockdown significantly reduced water content, increased lipid storage, and promoted the expression of genes related to lipid synthesis, but significantly blocked ovarian development, and induced forkhead box O (FOXO) gene expression in C. septempunctata under reproduction conditions. By contrast, injection of AKH peptide significantly inhibited FOXO expression, reduced lipid storage, and increased water content in C. septempunctata under diapause conditions.
These results indicate that CsAKH and CsAKHR are involved in the regulation of lipid accumulation and ovarian development during diapause in C. septempunctata, and provide a promising target for manipulating C. septempunctata diapause. © 2024 Society of Chemical Industry.
七星瓢虫是一种重要的捕食性昆虫，广泛用于防治蚜虫、粉虱、螨虫、蓟马和鳞翅目害虫。滞育调控技术是延长七星瓢虫货架期和商业化的关键。脂类积累是生殖滞育的主要特征，但 AKH 信号作为生殖滞育中脂类动员的调节剂的功能尚不清楚。本研究旨在鉴定和表征 AKH 和 AKHR 基因，并阐明它们在生殖滞育中的功能。
CsAKH 和 CsAKHR 的相对表达水平在头部和脂肪体中最高，在发育阶段和组织（头部、中肠、脂肪体和卵巢）中均显著降低。此外，CsAKH 和 CsAKHR 的表达在保幼激素（JH）注射后显著增加，但 CsMet 沉默显著抑制 CsAKH 和 CsAKHR 的表达，而 CsMet 敲低阻断了 JH 的诱导作用。CsAKH 和 CsAKHR 的敲低显著降低了水分含量，增加了脂质储存，并促进了与脂质合成相关的基因的表达，但显著阻断了卵巢发育，并在生殖条件下诱导了七星瓢虫的 forkhead box O (FOXO) 基因表达。相比之下，AKH 肽的注射显著抑制了 FOXO 的表达，减少了七星瓢虫滞育期的脂质储存和水分含量。
这些结果表明，CsAKH 和 CsAKHR 参与了七星瓢虫滞育期间的脂质积累和卵巢发育的调节，并为操纵七星瓢虫滞育提供了一个有前途的目标。© 2024 化学工业协会。
