AUTHOR=Cheng Tian , Veselská Tereza , Křížková Barbora , Švec Karel , Havlíček Václav , Stadler Marc , Kolařík Miroslav 

TITLE=Insight into the genomes of dominant yeast symbionts of European spruce bark beetle, Ips typographus

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1108975

DOI=10.3389/fmicb.2023.1108975

ISSN=1664-302X

ABSTRACT=<p>Spruce bark beetle <italic>Ips typographu</italic>s can trigger outbreaks on spruce that results in significant losses in the forest industry. It has been suggested that symbiotic microorganisms inhabiting the gut of bark beetles facilitate the colonization of plant tissues as they play a role in the detoxification of plant secondary metabolites, degrade plant cell wall and ameliorate beetle’s nutrition. In this study, we sequenced and functionally annotated the genomes of five yeasts <italic>Kuraishia molischiana</italic>, <italic>Cryptococcus</italic> sp., <italic>Nakazawaea ambrosiae</italic>, <italic>Ogataea ramenticola</italic>, and <italic>Wickerhamomyces bisporus</italic> isolated from the gut of <italic>Ips typographus</italic>. Genome analysis identified 5314, 7050, 5722, 5502, and 5784 protein coding genes from <italic>K. molischiana</italic>, <italic>Cryptococcus</italic> sp., <italic>N. ambrosiae</italic>, <italic>O. ramenticola</italic>, and <italic>W. bisporus</italic>, respectively. Protein-coding sequences were classified into biological processes, cellular and molecular function based on gene ontology terms enrichment. Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation was used to predict gene functions. All analyzed yeast genomes contain full pathways for the synthesis of essential amino acids and vitamin B6, which have nutritional importance to beetle. Furthermore, their genomes contain diverse gene families related to the detoxification processes. The prevalent superfamilies are aldo-keto reductase, ATP-binding cassette and the major facilitator transporters. The phylogenetic relationships of detoxification-related enzymes aldo-keto reductase, and cytochrome P450 monooxygenase, and ATP-binding cassette are presented. Genome annotations also revealed presence of genes active in lignocellulose degradation. <italic>In vitro</italic> analyses did not confirm enzymatic endolytic degradation of lignocellulose; however, all species can utilize and pectin and produce a large spectrum of exolytic enzymes attacking cellulose, chitin, and lipids.</p>