State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing, 400716, China; Chongqing Key Laboratory of Sericultural Science, Chongqing Engineering and Technology Research Center for Novel Silk Materials, Southwest University, Chongqing, 400716, China.
State Key Laboratory of Silkworm Genome Biology, Biological Science Research Center, Southwest University, Chongqing, 400716, China.
Insect Biochem Mol Biol. 2019 Jul;110:90-97. doi: 10.1016/j.ibmb.2019.04.012. Epub 2019 Apr 19.
Insect cuticle is considered an adaptable and versatile building material with roles in the construction and function of exoskeleton. Its physical properties are varied, as the biological requirements differ among diverse structures and change during the life cycle of the insect. Although the bulk of cuticle consists basically of cuticular proteins (CPs) associated with chitin, the degree of cuticular sclerotization is an important factor in determining its physical properties. Spodoptera litura, the tobacco cutworm, is an important agricultural pest in Asia. Compared to the domestic silkworm, Bombyx mori, another lepidopteran whose CP genes have been well annotated, S. litura has a shorter life cycle, hides in soil during daytime beginning in the 5th instar and is exposed to soil in the pupal stage without the protection of a cocoon. In order to understand how the CP genes may have been adapted to support the characteristic life style of S. litura, we searched its genome and found 287 putative cuticular proteins that can be classified into 9 CP families (CPR with three groups (RR-1, RR-2, RR-3), CPAP1, CPAP3, CPF, CPFL, CPT, CPG, CPCFC and CPLCA), and a collection of unclassified CPs named CPH. There were also 112 cuticular proteins enriched in Histidine residues with content varying from 6% to 30%, comprising many more His-rich cuticular proteins than B. mori. A phylogenetic analysis between S. litura, M. sexta and B. mori uncovered large expansions of RR-1 and RR-2 CPs, forming large gene clusters in different regions of S. litura chromosome 9. We used RNA-seq analysis to document the expression profiles of CPs in different developmental stages and tissues of S. litura. The comparative genomic analysis of CPs between S. litura and B. mori integrated with the unique behavior and life cycle of the two species offers new insights into their contrasting ecological adaptations.
昆虫外骨骼被认为是一种适应性强、用途广泛的建筑材料，在外骨骼的构建和功能中发挥作用。其物理性质多种多样，因为不同结构的生物学需求不同，而且在昆虫的生命周期中会发生变化。虽然外骨骼的大部分由与几丁质相关的角质蛋白（CP）组成，但角质硬化的程度是决定其物理性质的重要因素。斜纹夜蛾是亚洲重要的农业害虫。与已被充分注释 CP 基因的鳞翅目家蚕（Bombyx mori）相比，另一种鳞翅目昆虫斜纹夜蛾的生命周期更短，在 5 龄期开始时白天躲藏在土壤中，在蛹期暴露在土壤中，没有茧的保护。为了了解 CP 基因如何适应斜纹夜蛾的特征生活方式，我们搜索了其基因组，发现了 287 种可能的角质蛋白，可以分为 9 个 CP 家族（CPR 分为三组（RR-1、RR-2、RR-3）、CPAP1、CPAP3、CPF、CPFL、CPT、CPG、CPCFC 和 CPLCA）和一组未分类的 CP 命名为 CPH。还有 112 种富含组氨酸残基的角质蛋白，含量从 6%到 30%不等，比家蚕含有更多的 His 丰富的角质蛋白。斜纹夜蛾、烟草天蛾和家蚕之间的系统发育分析揭示了 RR-1 和 RR-2 CP 的大量扩张，在斜纹夜蛾染色体 9 的不同区域形成了大的基因簇。我们使用 RNA-seq 分析记录了不同发育阶段和组织中 CP 的表达谱。斜纹夜蛾和家蚕 CP 的比较基因组分析结合了这两个物种独特的行为和生命周期，为它们的生态适应提供了新的见解。
