Functional insights from the GC-poor genomes of two aphid parasitoids, Aphidius ervi and Lysiphlebus fabarum

• Published in: BMC genomics 2020-05, Vol.21 (1), p.376-27, Article 376
• Main Authors: Dennis, Alice B, Ballesteros, Gabriel I, Robin, Stéphanie, Schrader, Lukas, Bast, Jens, Berghöfer, Jan, Beukeboom, Leo W, Belghazi, Maya, Bretaudeau, Anthony, Buellesbach, Jan, Cash, Elizabeth, Colinet, Dominique, Dumas, Zoé, Errbii, Mohammed, Falabella, Patrizia, Gatti, Jean-Luc, Geuverink, Elzemiek, Gibson, Joshua D, Hertaeg, Corinne, Hartmann, Stefanie, Jacquin-Joly, Emmanuelle, Lammers, Mark, Lavandero, Blas I, Lindenbaum, Ina, Massardier-Galata, Lauriane, Meslin, Camille, Montagné, Nicolas, Pak, Nina, Poirié, Marylène, Salvia, Rosanna, Smith, Chris R, Tagu, Denis, Tares, Sophie, Vogel, Heiko, Schwander, Tanja, Simon, Jean-Christophe, Figueroa, Christian C, Vorburger, Christoph, Legeai, Fabrice, Gadau, Jürgen
• Format: Article
• Language: English
• Subjects: Analysis; Animals; Annotations; Aphid host; Aphidius ervi; Aphidoidea; Aphids; Aphids - genetics; Aphids - immunology; Arthropods; Asexuality; Biological control; Biological pest control; Chemoreception; Chemosensory perception; Codons; Coevolution; Comparative analysis; Cuticular hydrocarbons; de novo genome assembly; Deoxyribonucleic acid; Desaturase; DNA; DNA methylation; DNA Methylation - genetics; Endosymbionts; Energy efficiency; Evolution; Evolutionary genetics; Females; GC content; GC Rich Sequence; Gene expression; Genes; Genomes; Genomics; Host-parasite interactions; Hydrocarbons; Insect Proteins - genetics; Insects; Instrument industry (Equipment); Life cycles; Life Sciences; Lysiphlebus fabarum; Methylation; Mimicry; Nucleotides; Parasites; Parasitoid wasp; Parasitoids; Proteins; Sex determination; Sex Determination Processes - genetics; Success; Venom; Venoms; Venoms - genetics; Wasps; Wasps - genetics; Wasps - immunology
• ISSN: 1471-2164; 1471-2164
• DOI: 10.1186/s12864-020-6764-0

Parasitoid wasps have fascinating life cycles and play an important role in trophic networks, yet little is known about their genome content and function. Parasitoids that infect aphids are an important group with the potential for biological control. Their success depends on adapting to develop inside aphids and overcoming both host aphid defenses and their protective endosymbionts. We present the de novo genome assemblies, detailed annotation, and comparative analysis of two closely related parasitoid wasps that target pest aphids: Aphidius ervi and Lysiphlebus fabarum (Hymenoptera: Braconidae: Aphidiinae). The genomes are small (139 and 141 Mbp) and the most AT-rich reported thus far for any arthropod (GC content: 25.8 and 23.8%). This nucleotide bias is accompanied by skewed codon usage and is stronger in genes with adult-biased expression. AT-richness may be the consequence of reduced genome size, a near absence of DNA methylation, and energy efficiency. We identify missing desaturase genes, whose absence may underlie mimicry in the cuticular hydrocarbon profile of L. fabarum. We highlight key gene groups including those underlying venom composition, chemosensory perception, and sex determination, as well as potential losses in immune pathway genes. These findings are of fundamental interest for insect evolution and biological control applications. They provide a strong foundation for further functional studies into coevolution between parasitoids and their hosts. Both genomes are available at https://bipaa.genouest.org.