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Cocoonase is indispensable for Lepidoptera insects breaking the sealed cocoon
Tingting Gai1, Xiaoling Tong1, Minjin Han1
1State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, College of Biotechnology, Southwest University, Chongqing, China.
Plos Genetics
|September 28, 2020
Summary
Cocoonase is essential for moths to break free from their cocoons. Gene editing confirmed that without this enzyme, silkworms cannot escape, leading to novel cocoon control strategies.
Area of Science:
- * Insect biology and biochemistry
- * Evolutionary developmental biology
- * Genetics and genomics
Background:
- * Insects spin protective cocoons for pupal development, requiring a mechanism for adult emergence.
- * Cocoonase was previously identified as an enzyme involved in cocoon escape.
- * The evolutionary origins and precise function of cocoonase in cocoon-breaking remained unclear.
Purpose of the Study:
- * To investigate the evolutionary history and specificity of cocoonase in Lepidoptera.
- * To experimentally validate the role of cocoonase in adult moth emergence from sealed cocoons.
- * To explore potential applications in pest control and silk production.
Main Methods:
- * Bioinformatic analyses were used to trace the evolutionary trajectory of cocoonase.
- * CRISPR/Cas9 gene editing was employed to knock out the cocoonase gene in the silkworm Bombyx mori.
- * Phenotypic analysis of homozygous knock-out mutants was conducted to assess cocoon emergence.
Main Results:
- * Bioinformatics revealed cocoonase is specific to Lepidoptera and likely predates cocoon spinning.
- * Cocoonase evolved under purification selection in Lepidoptera, with stronger selection in species with sealed cocoons.
- * Homozygous cocoonase knock-out silkworms developed normally but were unable to escape their cocoons, dying within.
- Cocoonase is the critical enzyme enabling moths to break out of their cocoons. Gene editing confirmed its necessity for emergence, creating permanently intact cocoons and offering new pest control methods.
Conclusions:
- * Cocoonase is experimentally confirmed as the determining factor for breaking open cocoons.
- * The study provides the first direct evidence linking cocoonase function to adult emergence.
- * This research yields a novel silkworm strain and a potential strategy for managing cocoon-forming pests.
