Molecular Phylogeny Of The Genus Batracomorphus From China

The genus Batracomorphus belongs to Hemiptera,Cicadellidae,Iassinae,and Batracomorphini.It is the largest genus of the Iassinae,with more than 360 species recorded worldwide and 38 species distributed in China.There are many species in this genus,and the morphological characteristics among species are extremely similar,making accurate species identification more difficult.There are different views on its taxonomic status.Therefore,it is of great significance to study conduct a molecular phylogenetic study of Batracomorphus in China.In this study,the low-coverage genomic data of Batracomorphus were sequenced to obtain molecular markers for the mitochondrial genome,single-copy homologous genes,and ultraconserved elements;the structural features of the mitochondrial genome were analyzed to clarify the assembly and extraction of single-copy homologous genes and ultra-conservative elements.These three molecular markers were used to construct a phylogenetic tree of the genus Batracomorphus,respectively,to further explore the genetic relationship of this taxon.The main results are as follows:(1)Structural composition and analysis of the Batracomorphus mitogenomesIn this study,12 new(11 species of the Batracomorphus and 1 species of the Trocnadella)mitochondrial genomes were obtained based on the annotation of sequenced low-coverage genomic data from sequencing,in which comparative analysis showed that the mitochondrial genomes were all closed-loop double-stranded DNA molecules containing 37 coding genes;the length of the mitochondrial genomes ranged from 15,119-16,198 bp;and the nucleotide composition has a clear AT preference;the start codon of protein-coding genes is ATN(A/T/G/C),with ATG being the most frequently used start codon;TAG,TAA,and T--are usually used as stop codons.The arrangement of the mitochondrial genome is relatively conservative.This study only found that the t RNA genes of four species were rearranged,with rearrangements from trn I-trn Q-trn M to trn Q-trn I-trn M and the formation of a 38-352 bp non-coding region between trn Q and trn I.(2)Extraction and analysis of single-copy orthologs and ultraconserved elementsIn this study,low-coverage genomic data of 25 species of the Iassinae were sequenced,including 16 species of the Batracomorphus,and genomes were assembled based on short Illumina fragments.The assembled genomes ranged in size from 816.3Mb to 2,867.2 Mb,and the genome N50 lengths ranged from 48,630 bp to 216,067 bp.The assembled genome was used to obtain data of single-copy orthologs and ultraconserved elements,in which the coverage of single-copy orthologs gene extraction was 52.2-70.3%,and 1,310-1,765 gene markers were successfully captured;the extraction rate of ultraconserved elements was 76.58-82.50%,and 1,553-1,782 gene markers were extracted.It provides new molecular markers for further investigation of the phylogenetic relationship of the genus Batracomorphus.(3)Phylogenetic analyses of BatracomorphusIn this study,phylogenetic trees of Iassinae and Batracomorphus were constructed based on datasets of mitochondrial genomes,single-copy orthologs,and ultraconserved elements,respectively.The results show that Krisna was a paraphyletic group,the remaining Trocnadella,Batracomorphus,and Gessius were monophyletic groups,and Batracomorphus forms a sister group relationship with Trocnadella.Phylogenetic trees constructed using three molecular markers showed that the species involved in Batracomorphus formed three distinct clades.The phylogenetic relationships in the Batracomorphus Ⅰ branch were relatively stable,and the results all support that Batracomorphus curvatus,Batracomorphus thetis,and Batracomorphus matsumurai formed closely related species.There are differences in the topological structure of the three molecular markers in the Batracomorphus II branch,and the findings collectively support that Batracomorphus geminatus forms a sister group relationship with Batracomorphus paradentatus,and the genetic relationship of the remaining species was unstable.The phylogenetic relationships constructed by the three molecular markers in the Batracomorphus III branch were also unstable,but all supported that Batracomorphus notatus and Batracomorphus pandarus,Batracomorphus cocles and Batracomorphus strictus form sister groups with each other.