The complete mitochondrial genomes of two erythroneurine leafhoppers (Hemiptera, Cicadellidae, Typhlocybinae, Erythroneurini) with assessment of the phylogenetic status and relationships of tribes of Typhlocybinae

Abstract

The number and classification of tribes in the leafhopper subfamily Typhlocybinae are not yet fully clear, and molecular data has recently been used to help resolve the problem. In this study, the mitochondrial genomes of Mitjaevia shibingensis Chen, Song & Webb, 2020 and M. dworakowskae Chen, Song & Webb, 2020 of the tribe Erythroneurini (Cicadellidae, Typhlocybinae) were sequenced. Most protein-coding genes (PCGs) start with ATN and end with TAA or TAG, and the AT content of these three codons were found differ from previous results that show that the first codon has the highest incidence. Two rRNA genes are highly conserved, and the AT content in 16S is higher than that of 12S. The nucleotide diversity and genetic distance among 13 PCGs of the four tribes from Typhlocybinae show that Empoascini nucleotide diversity is significantly less than in the other three tribes, and have the largest distance from the others, while Typhlocybini and Zyginellini have the smallest distance, indicating that the relationship between the two is the closest. The nad2, nad4, nad4L, and nad5 genes have greater nucleotide diversity, showing potential for use as the main markers for species identification. The phylogenetic analysis yielded a well-supported topology with most branches receiving maximum support and a few branches pertaining to relationships within Zyginellini and Typhlocybini receiving lower support. The species of these two tribes are intertwined, and it was impossible to resolve them into separate branches. In addition, the tribes Empoascini and Erythroneurini were recovered as monophyletic, and Alebrini was placed at the base of the tree as the most primitive. These results are broadly in line with other molecular phylogenetical studies which differ from traditional morphological classification.

Structural Features and Phylogenetic Implications of 11 New Mitogenomes of Typhlocybinae (Hemiptera: Cicadellidae)

“…Here in our study, we support Zyginellini as a synonym of Typhlocybini, as treated or as the result revealed in phylogenetic studies based on molecular data of Typhlocybinae [4,8,22,57,60]. Inter-tribe relationships of the five monophyletic tribes are identical to the one obtained in the Anchored Hybrid Enrichment (AHE) based phylogenomics [6], with Alebrini sister to Empoascini as the basal branch, followed by the branch of Dikraneurini sister to Erythroneurini, and finally the branch with members of Typhlocybini and Zyginellini, indicating the relationships among the five monophyletic tribes are to some extent stable.…”

“…Some other tribal classification of Typhlocybinae having recognized 4-10 tribes that are too different from ours to be acceptable [58,59]. Here in our study, we support Zyginellini as a synonym of Typhlocybini, as treated or as the result revealed in phylogenetic studies based on molecular data of Typhlocybinae [4,8,22,57,60]. The cox1 gene is one of the most universal markers for identifying species and analyzing the phylogenetic relationships of leafhoppers [53][54][55], but it has the lowest Pi values, genetic distance and Ka/Ks rates, indicating it is the most conserved gene within the 13 PCGs among the 22 Typhlocybinae mitogenomes.…”

“…However, all members of Typhlocybini and Zyginellini are clustered into a clade, indicating that the two groups are mutually paraphyletic. This is similar to the studies of Ahmed (1983), Dietrich (2013) and Chen (2021) to some extent, that divided Typhlocybinae into five tribes: Alebrini, Dikraneurini (=Forcipatini), Empoascini (=Jorumini), Erythroneurini and Typhlocybini (=Eupterygini, Zyginellini) but different from the studies of Dworakowska (1979) and Zhang (1990) based on morphological data that divided Typhlocybinae into six tribes (Alebrini, Dikraneurini, Empoascini, Erythroneurini, Typhlocybini and Zyginellini) [3,8,9,56,57], although this is currently the most widely held tribal classification system of Typhlocybinae. Some other tribal classification of Typhlocybinae having recognized 4-10 tribes that are too different from ours to be acceptable [58,59].…”

“…Inter-tribe relationships of the five monophyletic tribes are identical to the one obtained in the Anchored Hybrid Enrichment (AHE) based phylogenomics [6], with Alebrini sister to Empoascini as the basal branch, followed by the branch of Dikraneurini sister to Erythroneurini, and finally the branch with members of Typhlocybini and Zyginellini, indicating the relationships among the five monophyletic tribes are to some extent stable. It is different from the sister-group relationship of Empoascini to Dikraneurini that proposed by Zhang (1990) and Xu (2021) based on morphological data and Dikraneurini to Typhlocybini and Zyginellini proposed by Chen (2021) based on molecular data [9,57,61]. Inter-tribe relationships of the five monophyletic tribes are identical to the one obtained in the Anchored Hybrid Enrichment (AHE) based phylogenomics [6], with Alebrini sister to Empoascini as the basal branch, followed by the branch of Dikraneurini sister to Erythroneurini, and finally the branch with members of Typhlocybini and Zyginellini, indicating the relationships among the five monophyletic tribes are to some extent stable.…”

“…Meanwhile, atp8 and nad2 are the fastest evolving genes, suggesting that atp8 and nad2 would be two ideal candidate markers for sibling species delimitation and population genetic differentiation in Typhlocybinae. locybinae into six tribes (Alebrini, Dikraneurini, Empoascini, Erythroneurini, Typhlocybini and Zyginellini) [3,8,9,56,57], although this is currently the most widely held tribal classification system of Typhlocybinae. Some other tribal classification of Typhlocybinae having recognized 4-10 tribes that are too different from ours to be acceptable [58,59].…”