Disruption of ecdysis in Leptinotarsa decemlineata by knockdown of chitin deacetylase 1
Disruption of ecdysis in Leptinotarsa decemlineata by knockdown of chitin deacetylase 1
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通过敲低几丁质脱乙酰酶 1 破坏 Leptinotarsa decemlineata 的蜕皮
DOI：
10.1016/j.aspen.2019.02.006
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发表时间：
2019-06-01
影响因子：
1.5
通讯作者：
Li, Guo-Qing
中科院分区：
文献类型：
--
作者：
Wu, Jian-Jian;Mu, Li-Li;Li, Guo-Qing
几丁质去乙酰化酶（CDAs）催化几丁质n -去乙酰化，是几丁质修饰的关键过程。本文从瘦藻（Leptinotarsa decemlineata）中鉴定出ldcdda1。它在幼虫的前肠、后肠和表皮中大量表达。在1、2、3龄幼虫蜕皮前，ldcdda1 mRNA水平较高。4龄（末龄）幼虫在蜕皮后第4天达到高峰。体内实验结果显示，LdCDA1对20-羟基蜕皮激素和幼激素滴度分别有正向和负向转录反应。此外，ldcdda1基因的敲低显著降低了叶片消耗，延长了发育周期，抑制了末龄幼虫的生长。ldcdda1 RNAi幼虫有三种不同的致死性表型。约30%的RNAi幼虫死亡；大约50%的变形蛹在成年后死亡；约20%的ldcdda1缺失蛹最终出现异常成虫，并在出蛹后1周内死亡。此外，ldcdda1 RNAi幼虫的几丁质含量较低，5种几丁质生物合成转录物（LdUAP1、LdUAP2、LdChSAa、LdChSAb和LdChSB） mRNA水平显著降低。此外，在LdCDA1缺失的亚形态中，葡萄糖、海藻糖和糖原含量增加，编码海藻糖和糖原合成酶的基因也高表达。这些发现提供了一个令人信服的证据，证明CDA1对L. decemlineata的几丁质沉积至关重要。此外，ldcdda1可能是控制幼虫的潜在靶点。
Chitin deacetylases (CDAs) catalyze N-deacetylation of chitin, a crucial process for chitin modification. In the present paper, LdCDA1 was identified in Leptinotarsa decemlineata. It was copiously expressed in larval foregut, hindgut and epidermis. Just before the molt in the first, second and third larval instars, the mRNA levels of LdCDA1 were high. In the fourth (final)-instar larvae, a peak occurred 4 days after ecdysis. In vivo results revealed that LdCDA1 transcriptionally responded, positively and negatively respectively, to 20-hydroxyecdysone and juvenile hormone titers. Moreover, knockdown of LdCDA1 significantly reduced foliage consumption, lengthened developing period and prevented growth in the final instar larvae. Three distinct lethal phenotypes were noted in the LdCDA1 RNAi larvae. About 30% of the RNAi larvae became moribund and finally died; approximately 50% of deformed pupae died as pharate adults; and around 20% of LdCDA1 depleted pupae finally emerged as abnormal adults and eventually died within 1 week after emergence. Furthermore, chitin content was low and the mRNA levels of five chitin biosynthesis transcripts (LdUAP1, LdUAP2, LdChSAa, LdChSAb and LdChSB) were significantly declined in the LdCDA1 RNAi larvae. In addition, glucose, trehalose and glycogen contents were increased in the LdCDA1 depleted hypomorphs, along with highly expressed genes coding for trehalose and glycogen synthesis enzymes. The findings provide a compelling piece of evidence that CDA1 is critical for chitin deposition in L. decemlineata. Moreover, LdCDA1 may be a potential target for control of the larvae.