Analysis of the Genetic Population Structure of Cacopsylla chinensis (Hemiptera: Psyllidae) with Mitochondrial DNA Markers in Saga and Yamaguchi prefectures, Japan

Abstract

DNA sequence analysis of the mitochondrial cytochrome oxidase I (COI)-leucine tRNA (tRNA Leu )-cytochrome oxidase II (COII) regions was performed to elucidate the phylogenetic relationships among 465 summer and winter-form psyllids from Saga and Yamaguchi prefectures in Japan. Multiple alignments of these sequences revealed 2 single-nucleotide polymorphisms (SNPs) at nucleotide positions 78 and 258 in the COI and tRNA Leu regions, respectively. Based on the nucleotide changes at these loci, these 465 insects were grouped into 3 genotypes: 78A/258A, 78G/258G, and 78G/258A. All but 2 of the 225 insects in Saga belonged to the genotype 78A/258A, and the 2 exceptions belonged to the genotype 78G/258G. Conversely, all the insects (105) collected from Shimonoseki city in western Yamaguchi prefecture belonged to the genotype 78G/258G, while eighty percent of the 135 samples from eastern Yamaguchi prefecture belonged to the genotype 78G/258G. Among the other 27 insect samples, 24 were 78G/258A and 3 were 78A/258A. Using POPTREE2, the psyllids were divided into 5 populations associated with the geographical distribution. The results suggest that the genetic population structure of these psyllids varied widely between Saga and Yamaguchi prefectures.

DNA barcoding of pear psyllids (Hemiptera: Psylloidea: Psyllidae), a tale of continued misidentifications

“…There is no evidence for the presence of west Palaearctic pear psyllids in East Asia, confirming the conclusions by Cho et al (2017) based on morphological evidence. Furthermore, Inoue et al (2012) and Katoh et al (2013Katoh et al ( , 2014 misidentified C. jukyungi from Japan as C. chinensis. They detected exceptionally high genetic differences from C. chinensis from Taiwan and concluded that the Japanese populations belong to a distinct lineage of the same species.…”

“…(2012) and Katoh et al . (2013, 2014) misidentified C. jukyungi from Japan as C. chinensis . They detected exceptionally high genetic differences from C. chinensis from Taiwan and concluded that the Japanese populations belong to a distinct lineage of the same species.…”

“…Kang et al rDNA of C. chinensis lineage III from Northeast China (Jilin and Heilongjang, near North Korea) by Chen et al (2018) and C. jukyungi from Korea are identical suggesting that the two taxa are conspecific and that the former constitutes a misidentification. Japanese (Katoh et al, 2014) and Korean C. jukyungi (of both summer and winter forms) sequences are monophyletic, supported by 99% bootstrap values in COI-tRNA leu -COII and 16S rDNA NJ trees (fig. 2).…”

“…This has been the most widely used method for DNA barcoding analyses (e.g. Yeh et al ., 1997; Shin et al ., 2013; Gwiazdowski et al ., 2015; Wu et al ., 2016; Amouroux et al ., 2017; Kanturski et al ., 2018; Song et al ., 2018), including previous studies on pear psyllids (Lee et al ., 2008; Kang et al ., 2012; Katoh et al ., 2013, 2014; Chen et al ., 2018). To compare our results with those papers, we preferred to use the same methodology despite some potential limitations, such as a poor fit of the K2P model at the species level (Srivathsan and Meier, 2012; Collins et al ., 2012).…”

“…Several recent molecular studies (Kang et al, 2012;Katoh et al, 2013Katoh et al, , 2014Cho and Lee, 2015;Chen et al, 2018) have addressed the problems of identity of and phylogenetic relationships between populations of pear psyllids. Judging from the respective GenBank entries, several of these sequences were attributed to the wrong species, adding to the confusion.…”