Improved reference quality genome sequence of the plastic-degrading greater wax moth, Galleria mellonella

Abstract

Galleria mellonella is a pest of honeybees in many countries because its larvae feed on beeswax. However, G. mellonella larvae can also eat various plastics, including polyethylene, polystyrene, and polypropylene, and therefore, the species is garnering increasing interest as a tool for plastic biodegradation research. This paper presents an improved genome (99.3% completed lepidoptera_odb10 BUSCO; genome mode) for G. mellonella. This 472 Mb genome is in 221 contigs with an N50 of 6.4 Mb and contains 13,604 protein-coding genes. Genes that code for known and putative polyethylene-degrading enzymes and their similarity to proteins found in other Lepidoptera are highlighted. An analysis of secretory proteins more likely to be involved in the plastic catabolic process has also been carried out.

Keywords: bioremediation; genome assembly; plastic degradation; polyethylene; secretory proteins; wax moth.

Fig. 1.

a) The taxonomic distribution of HMM hits across all eukaryotic hits, with clades of Metazoa, Arthropoda, Insecta, and Lepidoptera expanded accordingly. The number of significant hits per node is labeled, and the top 3 PFAM domains conserved across all eukaryotic HMM hits are displayed in the top left corner, with the number of sequence hits per model in text and the location of the domain in the model highlighted. b) The hit distribution from the HMM across species of Lepidoptera. Families are shown and the branch corresponding to G. mellonella is highlighted in magenta. The pie chart highlights the corresponding percentage of the HMM hits across the lepidopteran species after factoring out obsolete sequences.

Fig. 2.

Maximum likelihood phylogenetic tree constructed from the aligned 156 significant hits from HMM iteration on NCBI reference proteomes. The best-fit model was constructed according to the Bayesian information criterion: VT + F + G4. Source species are color coded, and bootstrap values are highlighted according to the legend. Locations of Demetra, Ceres, and Cibeles are marked with red, blue, and black circles, respectively.

Fig. 3.

Top 10 GO terms assigned to the identified secretory proteins under each of the biological process, cellular process, and molecular function classifications.