Comparative analysis five mitochondrial genomes of the subfamily Galerucinae (Coleoptera: Chrysomelidae) and evolution of control regions inferred from phylogeny

Shiwen Xu ¹ Pu Miao ² Qiaoqiao Liu ³ Fan Song ⁴ Hailin Yang ⁵ Zhenyuan Xia ^6* Weidong Huang ^4*

• ¹ China Agricultural University, Beijing, China
• ² Henan Province Tobacco Company, Luoyang, China
• ³ Department of Entomology, College of Plant Protection, South China Agricultural University, Guangzhou, China
• ⁴ Key Laboratory for Monitory and Green Control of Crop Pest, Department of Entomology, College of Plant Protection, China Agricultural University, Beijing, China
• ⁵ Yunnan Tobacco Company, Yuxi Branch, Yuxi, China
• ⁶ Yunnan Academy of Tobacco Agricultural Sciences, Kunming, China

Mitochondrial genome (mitogenome) is a widely utilized source of genetic data for animal species identification, molecular phylogeny, phylogeography, and evolutionary research at various taxonomic scales. With 14,500 recognized species placed in over 1,100 genera, Galerucinae (Coleoptera: Chrysomelidae), also known as leaf beetles, is the largest subfamily within Chrysomelidae. Here, we newly sequenced and annotated five mitogenomes from Galerucinae. The length of mitogenomes ranged from 15,737 to 16,484 bp. All of these mitogenomes exhibited high AT content, as well as positive AT skew and negative GC skew. Most protein-coding genes have ATN as their start codons, and TAA and TAG were the most widely assigned stop codons. The substitution rate analysis suggested that ATP8 experienced positive selection, while COX1 underwent purifying selection. Phylogenetic analyses derived from 13 protein-coding genes and two rRNAs showed that both tribes Alticini and Galerucini were monophyletic sister groups. Within two tribes, most groups and subtribes were monophyletic. We further estimated the divergence times within the Galerucinae using three calibration nodes in MCMCTree, dating the origin of Galerucinae to the Middle Cretaceous period (102.69 Ma), and indicated main groups of Galerucinae diverged and occurred during the period from Middle Cretaceous to Middle Paleogene. Furthermore, we investigated the structural features of the control regions (CRs) within the phylogenetic framework of Galerucinae. The analysis revealed variations in the length and structural organization of the CRs , and the placement of "problematic" genera was consistent with previous studies even among closely related groups, which can be attributed to variations in specific structural elements.