Abstract
Simple SummaryDrabescini comprises over 225 species and 46 genera with a highly diverse tribe of Deltocephalinae. These species serve as vectors of numerous agricultural plant pathogens and also transmit plant viruses to host plants. Previous phylogenetic analyses in this tribe mainly focused on morphological characters and were restricted to several gene fragments. Furthermore, the taxonomic status and phylogenetic relationships of this tribe need to be further studied. Therefore, the mitogenome may provide additional molecular evidence to reconstruct the phylogeny of this group and further elucidate relationships among major lineages. In this study, we sequenced and analyzed two newly complete mitogenomes including Drabescus ineffectus and Roxasellana stellata. These two mitogenomes contain 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes and the non-coding structure called A + T-control region. The Drabescini mitogenomes are highly conserved in base content and composition, genome size and order, protein-coding genes and codon usage, and secondary structure of tRNAs. Phylogenetic analyses using Bayesian inference and maximum likelihood methods indicated strong support for the monophyly of Drabescini. These results provide the comprehensive framework and valuable data toward the future resolution of phylogenetic relationships in this tribe.To explore the mitogenome characteristics and shed light on the phylogenetic relationships and molecular evolution of Drabescini species, we sequenced and analyzed the complete mitochondrial genome of two species including Drabescus ineffectus and Roxasellana stellata. The complete mitogenomes of D. ineffectus and R. stellata are circular, closed and double-stranded molecules with a total length of 15744 bp and 15361 bp, respectively. These two newly sequenced mitogenomes contain the typical 37 genes. Most protein-coding genes (PCGs) began with the start codon ATN and terminated with the terminal codon TAA or TAG, with an exception of a special initiation codon of ND5, which started with TTG, and an incomplete stop codon T-- was found in the Cytb, COX2, ND1 and ND4. All tRNAs could be folded into the canonical cloverleaf secondary structure except for the trnS1, which lacks the DHU arm and is replaced by a simple loop. The multiple tandem repeat units were found in A + T-control region. The sliding window, Ka/Ks and genetic distance analyses indicated that the ATP8 presents a high variability and fast evolutionary rate compared to other PCGs. Phylogenetic analyses based on three different datasets (PCG123, PCG12R and AA) using both Bayesian inference (BI) and maximum likelihood (ML) methods showed strong support for the monophyly of Drabescini.
Highlights
Deltocephalinae is the largest subfamily of leafhoppers, presenting distinct diagnostic characteristics and including over 6600 described extant species and 39 tribes widely distributed in all zoogeographic regions [1]
The genomes are of medium-sized sequence lengths compared to the other three Drabescini mitogenomes, ranging from 12,297 bp (Dryadomorpha sp., partial genome) to 15,309 bp (D. nuchalis) (Table S3)
The gene order is in accordance with original mitochondrial genome arrangements and other Drabescini mitogenomes
Summary
Deltocephalinae is the largest subfamily of leafhoppers, presenting distinct diagnostic characteristics and including over 6600 described extant species and 39 tribes widely distributed in all zoogeographic regions [1]. Drabescini leafhoppers are often found on woody hosts and shrubs in Old World tropical or deciduous forests and have been collected at light [2,3] These species feed on the sap of a variety of vascular plants via piercing-sucking mouthparts, serving as vectors of numerous agricultural plant pathogens and transmitting plant viruses to host plants. Previous studies in this tribe mostly concentrated on taxonomic descriptions and morphological characters of the nymphs [4,5,6,7]. Recent phylogenomic analysis using the anchored hybrid enrichment method showed support for the monophyly of this tribe [10] These phylogenetic analyses mainly depended on morphological characters and were restricted to several gene fragments. A new method examining the mitochondrial genome (mitogenome) may provide additional molecular evidence to reconstruct the phylogeny of this group and further elucidate relationships among major lineages
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