Genome-wide annotation and comparative analysis of cuticular protein genes in the noctuid pest Spodoptera litura
Genome-wide annotation and comparative analysis of cuticular protein genes in the noctuid pest Spodoptera litura
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DOI：
10.1016/j.ibmb.2019.04.012
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发表时间：
2019-07-01
影响因子：
3.8
通讯作者：
Mita, Kazuei
中科院分区：
文献类型：
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作者：
Liu, Jianqiu;Li, Shenglong;Mita, Kazuei
昆虫角质层被认为是一种适应性强、用途广泛的建筑材料，在外骨骼的构造和功能中发挥着重要作用。由于不同结构的生物学要求不同以及昆虫生命周期中的变化，其物理特性也各不相同。尽管大部分角质层基本上由与几丁质相关的角质蛋白（CP）组成，但角质层硬化程度是决定其物理特性的重要因素。斜纹夜蛾（Spodoptera litura），即烟草地老虎，是亚洲重要的农业害虫。与CP基因已被充分注释的另一种鳞翅目家蚕家蚕相比，斜纹夜蛾的生命周期较短，从第5龄开始白天隐藏在土壤中，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 个假定的角质层蛋白，可分为 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），以及一组名为CPH。还有112种富含组氨酸残基的角质层蛋白，含量从6%到30%不等，比家蚕含有更多的富含组氨酸的角质层蛋白。 S. litura、M. sexta 和 B. mori 之间的系统发育分析发现 RR-1 和 RR-2 CP 的大量扩展，在 S. litura 9 号染色体的不同区域形成大型基因簇。我们使用 RNA-seq 分析来记录 CP 在 S. litura 不同发育阶段和组织中的表达谱。对斜纹夜蛾和家蚕的 CP 进行比较基因组分析，并结合这两个物种的独特行为和生命周期，为了解它们对比的生态适应提供了新的见解。
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.