Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/5/2011
Publication Date: N/A
Citation: Interpretive Summary: The current study represents the first attempt to survey cox1 and cox2 mtDNA variation within the genus Lygus and, especially, within L. lineolaris and to use those genes to construct a molecular phylogeny for the same species. Further investigation is needed to resolve the discrepancies between morphological and molecular characteristics among these taxa.
Technical Abstract: The genus Lygus is widely distributed in North American and Eurasian continents. It is the most-studied genus in the family Miridae. However, very less information on the genetic diversity of this genus is available. Studying genetic variation among Lygus pest species and thereby constructing a molecular phylogeny for the genus were the major objectives of this study. Host plant association was also studied. Two mitochondrial DNA (mtDNA) genes, cytochrome oxidase 1 and cytochrome oxidase 2 (i.e., cox1 and cox2, respectively), were utilized to investigate inter- and intraspecific genetic diversity of major North American Lygus species. The 768-bp (base pair) region overlapping cox1 and cox2 genes as well as the 658-bp mitochondrial barcode region (cox1) were sequenced. Eight Lygus species collected from multiple sites in North America and Europe were analyzed for the monophyly or paraphyly using cox1 and cox2 mtDNA markers. Phylograms were constructed using the mtDNA data obtained from these phylogenetic methods. The tarnished plant bug, L. lineolaris (Palisot de Beauvois), is a highly polyphagous consumer of both crops and native plants including weeds. An association between genetic structuring and geography was observed in three identified disparate regions of North America. Neighbor-joining, maximum parsimony, Bayesian inference analysis, and maximum likelihood phylogenetic trees suggested that most L. lineolaris individuals belong to two closely related clades displaying sympatric distribution as well as a geographical frequency bias. Morphological identities of five L. lineolaris samples that formed an outlier clade indicated incongruence between genetic data and morphological identity. Phylogenetic analyses of mitochondrial DNA of four Lygus species (L. lineolaris, L. plagiatus Uhler, L. rugulipennis Poppius, and L. vanduzeei Knight) in the genus showed strong support for monophyly. However, L. borealis Kelton, L. elisus Van Duzee, L. hesperus Knight, L. keltoni Schwartz and Foottit, and L. solidaginis (Kelton) were not monophyletic. The current study represents the first attempt to survey cox1 and cox2 mtDNA variation within the genus Lygus and, especially, within L. lineolaris and to use those genes to construct a molecular phylogeny for the same species. Further investigation is needed to resolve the discrepancies between morphological and molecular characteristics among these taxa.