Souza Natalia M, Wang Tianfang, Suwansa-Ard Saowaros, Nahrung Helen F, Cummins Scott F
Tropical Fruit and Market Access RD&E, Horticulture and Forestry Science, Department of Agriculture and Fisheries, Portsmith, QLD 4870, Australia.
Centre for Bioinnovation, University of the Sunshine Coast, Maroochydore 4558, QLD, Australia.
Heliyon. 2022 Sep 6;8(9):e10516. doi: 10.1016/j.heliyon.2022.e10516. eCollection 2022 Sep.
Insects of different orders produce elaborate structures to protect their eggs from the many threats they may face from the environment and natural enemies. In the weevil genus , their dark, hardened egg capsule is possibly generated by a mixture of the insects' excrement and glandular substances. To test this hypothesis, this study focused on the elucidation of protein components present in the egg capsule cover and interrogated them through comparative analysis and gene expression to help infer potential functions. First, female sp. n. 2 reproductive and alimentary tissues were isolated to establish a reference transcriptome-derived protein database. Then, proteins from weevil frass (excrement) and egg capsule cover were identified through mass spectrometry proteomics. We found that certain egg capsule cover proteins were both exclusive and shared between frass and egg capsule cover, including those of plant origin (e.g. photosystem II protein) and others secreted by the weevil, primarily from reproductive tissue. Among them, a mucin/spidroin-like protein and novel proteins with repetitive units that likely play a structural role were identified. We have confirmed the dual origin of the egg capsule cover substance as a blend of the insects' frass and secretions. Novel proteins secreted by the weevils are key candidates for holding the egg case cover together.
不同目的昆虫会产生精巧的结构来保护它们的卵免受来自环境和天敌的诸多威胁。在象鼻虫属中，它们深色、坚硬的卵囊可能是由昆虫的粪便和腺体物质混合而成。为了验证这一假设，本研究着重于阐明卵囊覆盖物中存在的蛋白质成分，并通过比较分析和基因表达对其进行探究，以帮助推断潜在功能。首先，分离出象鼻虫新种2的雌性生殖和消化组织，建立一个基于转录组的蛋白质参考数据库。然后，通过质谱蛋白质组学鉴定象鼻虫粪便（排泄物）和卵囊覆盖物中的蛋白质。我们发现，某些卵囊覆盖物蛋白质在粪便和卵囊覆盖物中既有独特的，也有共有的，包括植物来源的蛋白质（如光系统II蛋白）以及象鼻虫分泌的其他蛋白质，主要来自生殖组织。其中，鉴定出一种粘蛋白/类蜘蛛丝蛋白以及具有重复单元、可能起结构作用的新蛋白质。我们已经证实卵囊覆盖物物质的双重来源是昆虫粪便和分泌物的混合物。象鼻虫分泌的新蛋白质是将卵壳覆盖物结合在一起的关键候选物质。
