Department of Plant Protection, College of Agriculture, Bu-Ali Sina University, Shahid Mostafa Ahmadi Roshan, Hamedan, Iran.
Department of Plant Quarantine Technology Center, Animal and Plant Quarantine Agency, Gimcheon, South Korea.
Arch Insect Biochem Physiol. 2021 Nov;108(3):e21840. doi: 10.1002/arch.21840. Epub 2021 Sep 26.
Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), the cotton bollworm, is a destructive pest which is famous for its resistance to a variety of insecticides. RNA interference is a posttranscriptional gene silencing mechanism that has become a popular tool to control insect pests, triggered by double-stranded RNAs (dsRNAs). The effect of ingestion and injection delivery methods of dsRNA related to some protease genes including Trypsin (Ha-TRY39 and Ha-TRY96), Chymotrypsin (Ha-CHY), and Cathepsin L (Ha-CAT) on growth and development of H. armigera was investigated in this study. All protease genes encoded full ORFs and were expressed in all H. armigera larvae stages and tissues. In both injection and feeding bioassays, Ha-RNAi CHY's performance outperformed that of other protease genes. CHY enzyme activity in the midgut of larvae was significantly reduced after treatment with ds-HaCHY. Oral administration of ds-CHY also resulted in significant mortality of H. armigera larvae. However, because of the high RNase activity in the midgut lumen of lepidoptera, a large amount of dsRNA was needed to effectively kill instars of H. armigera. To reduce dsRNA degradation, bacterial expression and dsRNA formulation were used. After oral administration, it was toxic to H. armigera larvae. Before oral administration, bacterial cells were sonicated to increase dsRNA release. The RNA interference efficiency of sonicated bacteria was significantly increased, resulting in higher larval mortality when administered orally. All of these findings point to Ha-CHY as a new candidate for developing an effective dsRNA-based pesticide for H. armigera control.
棉铃虫（Helicoverpa armigera）（鳞翅目：夜蛾科）是一种具有破坏性的害虫，以对各种杀虫剂产生抗性而闻名。RNA 干扰是一种转录后基因沉默机制，已成为控制害虫的一种流行工具，由双链 RNA（dsRNA）触发。本研究探讨了双 RNA 摄入和注射传递方法与包括胰蛋白酶（Ha-TRY39 和 Ha-TRY96）、糜蛋白酶（Ha-CHY）和组织蛋白酶 L（Ha-CAT）在内的一些蛋白酶基因的关系，对棉铃虫生长发育的影响。所有蛋白酶基因均编码完整的开放阅读框，并在棉铃虫幼虫的所有阶段和组织中表达。在注射和喂养生物测定中，Ha-RNAi CHY 的表现优于其他蛋白酶基因。ds-HaCHY 处理后，幼虫中 CHY 酶活性显著降低。口服 ds-CHY 也导致棉铃虫幼虫死亡率显著增加。然而，由于鳞翅目昆虫中肠腔中的核糖核酸酶活性较高，需要大量的 dsRNA 才能有效杀死棉铃虫的龄期。为了减少 dsRNA 降解，使用了细菌表达和 dsRNA 配方。口服后，它对棉铃虫幼虫有毒。在口服给药之前，细菌细胞被超声处理以增加 dsRNA 的释放。超声处理细菌的 RNA 干扰效率显著提高，口服给药时幼虫死亡率更高。所有这些发现都表明 Ha-CHY 是开发有效基于 dsRNA 的棉铃虫防治农药的新候选基因。
