Genomic Analyses of the Fungus Paraconiothyrium sp. Isolated from the Chinese White Wax Scale Insect Reveals Its Symbiotic Character

Abstract

The Chinese white wax scale, Ericerus pela, is an insect native to China. It harbors a variety of microbes. The Paraconiothyrium fungus was isolated from E. pela and genome sequenced in this study. A fungal cytotoxicity assay was performed on the Aedes albopictus cell line C6/36. The assembled Paraconiothyrium sp. genome was 39.55 Mb and consisted of 14,174 genes. The coding sequences accounted for 50.75% of the entire genome. Functional pathway analyses showed that Paraconiothyrium sp. possesses complete pathways for the biosynthesis of 20 amino acids, 10 of which E. pela lacks. It also had complementary genes in the vitamin B groups synthesis pathways. Secondary metabolism prediction showed many gene clusters that produce polyketide. Additionally, a large number of genes associated with ‘reduced virulence’ in the genome were annotated with the Pathogen–Host Interaction database. A total of 651 genes encoding carbohydrate-active enzymes were predicted to be mostly involved in plant polysaccharide degradation. Pan-specific genomic analyses showed that genes unique to Paraconiothyrium sp. were enriched in the pathways related to amino acid metabolism and secondary metabolism. GO annotation analysis yielded similar results. The top COG categories were ‘carbohydrate transport and metabolism’, ‘lipid transport and metabolism’, and ‘secondary metabolite biosynthesis, transport and catabolism’. Phylogenetic analyses based on gene family and pan genes showed that Paraconiothyrium sp is clustered together with species from the Didymosphaeriaceae family. A multi-locus sequence analysis showed that it converged with the same branch as P. brasiliense and they formed one group with fungi from the Paraconiothyrium genus. To validate the in vitro toxicity of Paraconiothyrium sp., a cytotoxicity assay was performed. The results showed that medium-cultured Paraconiothyrium sp. had no harmful effect on cell viability. No toxins were secreted by the fungus during growth. Our results imply that Paraconiothyrium sp. may establish a symbiotic relationship with the host to supply complementary nutrition to E. pela.

The Complete Mitochondrial Genome of the Chinese White Wax Scale Insect, Ericerus pela Chavannes (Hemiptera: Coccidae), with Novel Gene Arrangement and Truncated tRNA Genes

“…E. pela had an extremely biased A + T content of 88.21%, higher than all the other nine Coccoidea species, which indicated an adaptation to a significantly high requirement for nitrogen. This was in accordance with the existence of symbiotic fungi, which could also serve as a nitrogen provider in vivo E. pela [ 18 ].…”

“…Most Coccoidea species are agriculture and forestry pests, except for very few species with a high economic value, such as the Chinese white wax scale insect Ericerus pela (Chavannes, 1848) [ 17 ]. Previous work has related to E. pela ’s use in biological research, molecular research, and the popularization of relevant applications [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. Regarding its breeding history, people initially started to collect white wax as early as approximately the 3rd century AD in China [ 26 ].…”

Whole-genome sequencing and functional annotation of pathogenic Paraconiothyrium brasiliense causing human cellulitis

“…As well as virulence factors, secondary metabolites play an important role in fungal pathogenicity in humans [ 16 ]. Paraconiothyrium brasiliense produces various secondary metabolites, including terpenes, polyketides, and aromatic compounds that have a wide range of biological activities [ 17 ]. In this study, we identified 27 genes encoding DFVF-HUM involved in secondary metabolite synthesis and four genes related to terpenoid metabolism, which were associated with human disease.…”

Analyses of the Complete Mitochondrial Genome of Paraconiothyrium sp. and Gene Rearrangement Diversity in the Pleosporales

“…Previously, we successfully isolated the fungi Paraconiothyrium sp. YMF1.07793 from the Chinese white wax scale insect (Ericerus pela) and revealed the existence of a symbiotic relationship between the fungus symbiont and the host based on amino acid and vitamin metabolic complementation [9].…”