Molecular evolution of glycoside hydrolase genes in the Western corn rootworm (Diabrotica virgifera virgifera).
Cellulose is an important nutritional resource for a number of insect herbivores. Digestion of cellulose and other polysaccharides in plant-based diets requires several types of enzymes including a number of glycoside hydrolase (GH) families. In a previous study, we showed that a single GH45 gene is present in the midgut tissue of the western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae). However, the presence of multiple enzymes was also suggested by the lack of a significant biological response when the expression of the gene was silenced by RNA interference. In order to clarify the repertoire of cellulose-degrading enzymes and related GH family proteins in D. v. virgifera, we performed next-generation sequencing and assembled transcriptomes from the tissue of three different developmental stages (eggs, neonates, and third instar larvae). Results of this study revealed the presence of seventy-eight genes that potentially encode GH enzymes belonging to eight families (GH45, GH48, GH28, GH16, GH31, GH27, GH5, and GH1). The numbers of GH45 and GH28 genes identified in D. v. virgifera are among the largest in insects where these genes have been identified. Three GH family genes (GH45, GH48, and GH28) are found almost exclusively in two coleopteran superfamilies (Chrysomeloidea and Curculionoidea) among insects, indicating the possibility of their acquisitions by horizontal gene transfer rather than simple vertical transmission from ancestral lineages of insects. Acquisition of GH genes by horizontal gene transfers and subsequent lineage-specific GH gene expansion appear to have played important roles for phytophagous beetles in specializing on particular groups of host plants and in the case of D. v. virgifera, its close association with maize.
School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America.
Seong-il
SI
Eyun
Department of Entomology, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America.
Haichuan
H
Wang
Department of Entomology, Max Planck Institute for Chemical Ecology, Jena, Germany.
Yannick
Y
Pauchet
Department of Entomology, Max Planck Institute for Chemical Ecology, Jena, Germany.
Richard H
RH
Ffrench-Constant
Food Science and Technology, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America.
Andrew K
AK
Benson
Department of Entomology, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America; Biosciences, University of Exeter, Penryn, United Kingdom; Departamento de Producción Agropecuaria, Facultad de Ciencias Agropecuarias, Universidad de Caldas, Manizales, Colombia.
Arnubio
A
Valencia-Jiménez
School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America; Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America.
Etsuko N
EN
Moriyama
Department of Entomology, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America.
Blair D
BD
Siegfried
D000595:Amino Acid Sequence; D000818:Animals; D001517:Coleoptera / Q000235:genetics*; D019143:Evolution, Molecular; D018507:Gene Expression Regulation, Developmental; D017344:Genes, Insect; D006026:Glycoside Hydrolases / Q000096:biosynthesis / Q000145:classification / Q000235:genetics*; D019476:Insect Proteins / Q000096:biosynthesis / Q000145:classification / Q000235:genetics*; D007814:Larva / Q000201:enzymology; D008969:Molecular Sequence Data; D010063:Ovum / Q000201:enzymology; D010802:Phylogeny; D034622:RNA Interference; D016415:Sequence Alignment; D017423:Sequence Analysis, RNA; D017386:Sequence Homology, Amino Acid; D059467:Transcriptome
D019476:Insect Proteins; D006026:Glycoside Hydrolases