Multifaceted biological insights from a draft genome sequence of the tobacco hornworm moth, Manduca sexta

Abstract

Manduca sexta, known as the tobacco hornworm or Carolina sphinx moth, is a lepidopteran insect that is used extensively as a model system for research in insect biochemistry, physiology, neurobiology, development, and immunity. One important benefit of this species as an experimental model is its extremely large size, reaching more than 10 g in the larval stage. M. sexta larvae feed on solanaceous plants and thus must tolerate a substantial challenge from plant allelochemicals, including nicotine. We report the sequence and annotation of the M. sexta genome, and a survey of gene expression in various tissues and developmental stages. The Msex_1.0 genome assembly resulted in a total genome size of 419.4 Mbp. Repetitive sequences accounted for 25.8% of the assembled genome. The official gene set is comprised of 15,451 protein-coding genes, of which 2498 were manually curated. Extensive RNA-seq data from many tissues and developmental stages were used to improve gene models and for insights into gene expression patterns. Genome wide synteny analysis indicated a high level of macrosynteny in the Lepidoptera. Annotation and analyses were carried out for gene families involved in a wide spectrum of biological processes, including apoptosis, vacuole sorting, growth and development, structures of exoskeleton, egg shells, and muscle, vision, chemosensation, ion channels, signal transduction, neuropeptide signaling, neurotransmitter synthesis and transport, nicotine tolerance, lipid metabolism, and immunity. This genome sequence, annotation, and analysis provide an important new resource from a well-studied model insect species and will facilitate further biochemical and mechanistic experimental studies of many biological systems in insects.

Genomic adaptation to polyphagy and insecticides in a major East Asian noctuid pest

“…In the other, six sets of S. litura chromosomes were fused, corresponding to six H. melpomene chromosomes (N = 21) 11 , and another eight S. litura chromosomes were fused, corresponding to four other H. melpomene chromosomes. These changes were consistent with previous reports on chromosome evolution among butterflies including Melitaea cinxia 12 and the moth Manduca sexta 13 …”

Toll ligand Spätzle3 controls melanization in the stripe pattern formation in caterpillars

“…S3A), this report shows that an spz gene is involved in the melanization process. It has been reported that Spz-1 works as a ligand of Toll-1 and that the Toll signaling pathway is involved in dorsoventral axis formation (19), muscle development during embryogenesis (32), and the induction of antimicrobial peptide expression in innate immunity (33,34) (Fig. 5B).…”

“…5B). The initial step in both pathways is to recognize the lysine-containing peptidoglycan and β-1,3-glucan from the cell wall of Gram-positive bacteria and fungi by peptidoglycan recognition proteins and β-1,3-glucan recognition proteins, respectively, which are followed by independent serine-protease cascades in the two pathways (33,34) (Fig. 5B).…”

“…42 and 43 should be included on page 8340, left column, second paragraph, line 23, where the reference callout "(33, 34)" should instead appear as " (33,34, 42, 43)." Also, on the same page, right column, first full paragraph, line 4, the reference callout "(36)" should instead appear as "(36, 42)."…”

“…Also, on the same page, right column, first full paragraph, line 4, the reference callout "(36)" should instead appear as "(36, 42)." Lastly, in the same paragraph, line 9, the reference callout "(33, 34)" should instead appear as " (33,34, 42, 43)." …”