Abstract：
In insects, the expression of 20E response genes that initiate metamorphosis is triggered by a pulse of 20-hydroxyecdysone (20E). The 20E pulse is generated through two processes: synthesis, which increases its level, and inactivation, which decreases its titer. CYP18A1 functions as an ecdysteroid 26-hydroxylase and plays a role in 20E removal in several representative insects. However, applying 20E degradation activity of CYP18A1 to other insects remains a significant challenge. In this study, we discovered high levels of Hvcyp18a1 during the larval and late pupal stages, particularly in the larval epidermis and fat body of Henosepilachna vigintioctopunctata, a damaging Coleopteran pest of potatoes. RNA interference (RNAi) targeting Hvcyp18a1 disrupted the pupation. Approximately 75% of the Hvcyp18a1 RNAi larvae experienced developmental arrest and remained as stunted prepupae. Subsequently, they gradually turned black and eventually died. Among the Hvcyp18a1-depleted animals that successfully pupated, around half became malformed pupae with swollen elytra and hindwings. The emerged adults from these deformed pupae appeared misshapen, with shriveled elytra and hindwings, and were wrapped in the pupal exuviae. Furthermore, RNAi of Hvcyp18a1 increased the expression of a 20E receptor gene (HvEcR) and four 20E response transcripts (HvE75, HvHR3, HvBrC, and HvαFTZ-F1), while decreased the transcription of HvβFTZ-F1. Our findings confirm the vital role of CYP18A1 in the pupation, potentially involved in the degradation of 20E in H. vigintioctopunctata.
摘要：
在昆虫中，引发变态的20E反应基因的表达是由20-羟基蜕皮激素脉冲(20E)触发的。20E脉冲通过两个过程产生：合成，这增加了它的水平，和失活，这降低了它的滴度。CYP18A1充当蜕皮类固醇26-羟化酶，并在几种代表性昆虫的20E去除中起作用。然而,将CYP18A1的20E降解活性应用于其他昆虫仍然是一个重大挑战。在这项研究中,我们在幼虫和蛹后期发现了高水平的Hvcyp18a1，特别是在Henosepilachnavigintioctopunctata的幼虫表皮和脂肪体内，马铃薯的一种有害鞘翅目害虫。靶向Hvcyp18a1的RNA干扰（RNAi）破坏了化蛹。大约75％的Hvcyp18a1RNAi幼虫经历了发育停滞，并保持发育迟缓。随后，他们逐渐变黑，最终死亡。在成功化p的Hvcyp18a1耗尽的动物中，大约一半变成畸形的p，带有肿胀的鞘翅和后翅。这些畸形蛹中出现的成虫出现畸形，干涸的埃利特拉和后翅，包裹在蛹中。此外，Hvcyp18a1的RNAi增加了20E受体基因（HvEcR）和四种20E反应转录本（HvE75，HvHR3，HvBrC，和HvαFTZ-F1)，同时降低了HvβFTZ-F1的转录。我们的发现证实了CYP18A1在化蛹中的重要作用，可能参与H.vigintioctopunctata中20E的降解。
