Liu Jing, Yang Yuhang, Yan Zihan, Wang Haishan, Bai Ming, Shi Chengmin, Li Jing
College of Plant Protection, Hebei Agricultural University, Baoding 071000, China.
Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
Biology (Basel). 2023 Jan 14;12(1):135. doi: 10.3390/biology12010135.
Helotid beetles are commonly found in places where sap flows from tree trunks and in crevices in bark. The Helotidae family is a rare and primitive group of Cucujoidea. To date, no complete mitochondrial (mt) genome has been sequenced for this family. To better understand the characteristics of the mt genome and the evolution of Cucujoidea, we sequenced and annotated the complete mt genomes of (Ritsema, 1895) and Lee, 2017 using next-generation sequencing. These are the first record of Helotidae mt genomes. The RNA secondary structures of both species were also predicted in this study. The mt genomes of and are circular, with total lengths of 16,112 bp and 16,401 bp, respectively. After comparing the mt genomes of and , we observed the gene arrangement, codon usage patterns, base content, and RNA secondary structures of both species to be similar, which has also been noted in other Coleoptera insects. The nucleotide sequence of the coding regions and the control region has small differences. The phylogenetic analysis indicated that Helotidae and Protocucujidae are sister groups and revealed the relationship between seven families; however, the validity of the two series (Erotylid series and Nitidulid series) as larger groups in the superfamily was not supported. The mt phylogenomic relationships have strong statistical support. Therefore, the division of Cucujoidea into series should be re-examined. Our results will provide a better understanding of the mt genome and phylogeny of Helotidae and Cucujoidea and will provide valuable molecular markers for further genetic studies.
扁甲科甲虫常见于树干有树液流出的地方以及树皮的裂缝中。扁甲科是拟步甲总科中一个罕见且原始的类群。迄今为止，该科尚未有完整的线粒体（mt）基因组被测序。为了更好地了解mt基因组的特征以及拟步甲总科的进化，我们使用下一代测序技术对（里特马，1895年）和李，2017年的完整mt基因组进行了测序和注释。这些是扁甲科mt基因组的首次记录。本研究还预测了这两个物种的RNA二级结构。和的mt基因组呈环状，总长度分别为16,112 bp和16,401 bp。在比较了和的mt基因组后，我们观察到这两个物种的基因排列、密码子使用模式、碱基含量和RNA二级结构相似，这在其他鞘翅目昆虫中也有发现。编码区和控制区的核苷酸序列存在微小差异。系统发育分析表明，扁甲科和原拟步甲科是姐妹群，并揭示了七个科之间的关系；然而，作为总科中较大类群的两个系列（红瓢虫系列和露尾甲系列）的有效性未得到支持。mt系统发育基因组关系具有很强的统计支持。因此，拟步甲总科的系列划分应重新审视。我们的结果将有助于更好地了解扁甲科和拟步甲总科的mt基因组和系统发育，并将为进一步的遗传研究提供有价值的分子标记。
