College of Plant Protection, Hebei Agricultural University, Baoding, China.
College of Plant Protection, Hebei Agricultural University, Baoding, China; Graduate School of Chinese Academy of Agricultural Sciences, Beijing, China.
Pestic Biochem Physiol. 2021 Mar;173:104770. doi: 10.1016/j.pestbp.2021.104770. Epub 2021 Jan 8.
Chitin deacetylases (CDAs, EC 3.5.1.41) catalyze the N-deacetylation of chitin to produce chitosan, which is essential for insect survival. Hence, CDAs are promising targets for the development of novel insecticidal drugs. In this study, the putative Group I chitin deacetylase genes HpCDA1, HpCDA2-1 and HpCDA2-2 were identified from Holotrichia parallela. Conserved domain database search identified a chitin-binding peritrophin-A domain (ChBD), a low-density lipoprotein receptor class A domain (LDLa), and a putative CDA-like catalytic domain. RT-qPCR analysis showed that the Group I HpCDAs were expressed in various tissues and predominant in the integument. The developmental expression patterns from the first-instar to third-instar larvae showed that HpCDAs were highly expressed on the first day and gradually declined after molting. The functional characteristics of the Group I CDAs in cuticle organization were examined using RNA interference (RNAi) and transmission electron microscopy (TEM) methods. Administration of double-stranded HpCDA (dsHpCDA) through larval injection could suppress the expression levels of HpCDA1 and HpCDA2, thus resulting in abnormal or lethal phenotypes. TEM analysis revealed that RNAi of either HpCDA1 or HpCDA2 remarkably affected the cuticle integrity, as evidenced by cuticle disorganization and chitin laminae disruption, suggesting the crucial role of CDAs in chitin modification. These experimental results demonstrate the important contribution of putative key genes involved in chitin metabolism, and provide a foundation for developing new strategies to control H. parallela.
几丁质脱乙酰酶（CDAs，EC 3.5.1.41）催化几丁质的 N-脱乙酰化生成壳聚糖，这对昆虫的生存至关重要。因此，CDAs 是开发新型杀虫剂的有前途的靶标。在这项研究中，从直纹稻弄蝶（Holotrichia parallela）中鉴定出假定的 I 组几丁质脱乙酰酶基因 HpCDA1、HpCDA2-1 和 HpCDA2-2。保守结构域数据库搜索鉴定出一个几丁质结合围食膜-A 结构域（ChBD）、低密度脂蛋白受体 A 结构域（LDLa）和一个假定的 CDA 样催化结构域。RT-qPCR 分析表明，I 组 HpCDAs 在各种组织中表达，在表皮中占优势。从第一龄幼虫到第三龄幼虫的发育表达模式表明，HpCDAs 在第一天高度表达，蜕皮后逐渐下降。使用 RNA 干扰（RNAi）和透射电子显微镜（TEM）方法研究了 I 组 CDAs 在表皮组织中的功能特征。通过幼虫注射给予双链 HpCDA（dsHpCDA）可以抑制 HpCDA1 和 HpCDA2 的表达水平，从而导致异常或致死表型。TEM 分析表明，HpCDA1 或 HpCDA2 的 RNAi 显著影响表皮完整性，表现为表皮组织紊乱和几丁质层破坏，表明 CDAs 在几丁质修饰中起着关键作用。这些实验结果证明了参与几丁质代谢的假定关键基因的重要贡献，并为开发控制直纹稻弄蝶的新策略提供了基础。
