Whole-genome Assembly And Comparative Analysis Of Apoderus Dimidiatus

Leaf-rolling weevil is a general term for insects of Attelabidae,belonging to Curculionoidea,Coleoptera,Insecta.The Leaf-rolling weevil is famous for its unique leafrolling behavior before laying eggs,in which it wraps the leaves of its host plant into a tube to protect the eggs it lays inside.The research about the Leaf-rolling weevil remains in the macroscopic aspects such as behavioral observation and morphological identification,and there are few pieces of research on the microscopic level.With the development of sequencing technology,more and more insect genomes have been analyzed,and the biological characteristics of insects have been explained from the molecular mechanism.In this study,the whole genome of Apoderus dimidiatus was sequenced,and a high-quality reference genome was constructed to enrich the genome data.Using the genomic data of Apoderus dimidiatus,we elucidated its phylogenetic position and then annotated its genome.Through comparative genomics analysis with other non-leaf-rolling beetles,we aimed to explore the molecular mechanisms underlying the evolution of leaf-rolling behavior in weevils.The research findings are as follows:(1)A high-quality chromosome-level of Apoderus dimidiatus reference genome was constructed by combining the second-and third-generation sequencing data and assisted by HiC technology The genome size was 619,259,538 bp,the average length was 434,568 bp,and the length of N50 was 50.89 Mb.(2)It indicates good integrity.Repeating sequence annotation found that the repetition rate of Apoderus dimidiatus was 64.78%,in which transposable elements accounted for the vast majority.By combining de novo prediction,homology prediction and transcriptome-assisted prediction,a total of 12,572 genes were predicted by EVM integration,and 82.59% of the functional genes were annotated,showing that their genetic characteristics were similar to those of the reference species.(3)The phylogenetic tree was constructed using direct homologous single-copy genes and the divergence time was calculated.The results showed that the divergence time between Diptera and Coleoptera was about 333.24 million years ago,the divergence time between Curculionidae and Tenebrionidae was approximately 197.34 million years ago,and the divergence time between Attelabidae and Curculionidae was approximately 161.52 million years ago.(4)A total of 334 extended gene families were identified in the genome of Apoderus dimidiatus,which might be related to the survival of Apoderus dimidiatus larvae in leaf rolls.The 1,718 contract gene families may have led to the evolution of leaf-rolling behavior by reducing the number of eggs laid and the survival of the offspring.The PAML software identified 106 rapidly evolving genes with significant signaling and 540 positive selection genes,which play an essential role in energy supply.Based on these findings,it is inferred that the contraction of contract gene families in leafrolling weevils leads to a decrease in egg production.In order to ensure population continuity,leaf-rolling weevils have evolved the special leaf-rolling behavior to hide their offspring.The positively selected genes are involved in providing sufficient energy during the leaf-rolling process.These discoveries provide genomic resources for further research on the Apoderus dimidiatus and insects of Attelabidae,offering new insights into the study of their unique leafrolling behavior.Furthermore,they provide data support for exploring new approaches for the control and management of leaf-rolling weevils.