A high-quality carabid genome provides insights into beetle genome evolution and cold adaptation

Abstract

The hyper-diverse order Coleoptera comprises a staggering ~25% of known species on Earth. Despite recent breakthroughs in next generation sequencing, there remains a limited representation of beetle diversity in assembled genomes. Most notably, the ground beetle family Carabidae, comprising more than 40,000 described species, has not been studied in a comparative genomics framework using whole genome data. Here we generate a high-quality genome assembly for Nebria riversi, to examine sources of novelty in the genome evolution of beetles, as well as genetic changes associated with specialization to high elevation alpine habitats. In particular, this genome resource provides a foundation for expanding comparative molecular research into mechanisms of insect cold adaptation. Comparison to other beetles shows a strong signature of genome compaction, with N. riversi possessing a relatively small genome (~147 Mb) compared to other beetles, with associated reductions in repeat element content and intron length. Small genome size is not, however, associated with fewer protein-coding genes, and an analysis of gene family diversity shows significant expansions of genes associated with cellular membranes and membrane transport, as well as protein phosphorylation and muscle filament structure. Finally, our genomic analyses show that these high elevation beetles have endosymbiotic Spiroplasma, with several metabolic pathways (e.g. propanoate biosynthesis) that might complement N. riversi, although its role as a beneficial symbiont or as a reproductive parasite remains equivocal.

Climatic niche conservatism and ecological diversification in the Holarctic cold-dwelling butterfly genusErebia

“…The origin of alpine endemic insects has complex drivers (Queiroz et al 2022), including allopatric speciation (Schoville and Roderick, 2010, Schat et al 2022, Todisco et al 2010), diversity dependent radiation (Condamine 2018), or interactions with endosymbionts (Lucek et al 2021, Weng et al 2021). We fill in new information into the mosaic describing diversification drivers of alpine insects in relation to the role of the evolution of their climatic niches.…”

Combined transcriptome and metabolome analysis of a new species of microalgae from Tibetan plateau and its response to sewage treatment

“…In our study, the results of both transcriptome and metabolome analyses showed that propanoate metabolism pathways were induced by sewage treatment and key genes related to propanoate metabolism (Table S5). Furthermore, the downregulated metabolite was 2-oxobutanoate (2-OBA), which as a toxic metabolic intermediate, generally arrests the cell growth of most microorganisms and blocks the biosynthesis of target metabolites [35-36]. In the wastewater treatment process, the metabolite of 2-OBA is downregulated, which can promote the effect of microalgae on wastewater treatment and maintain the normal metabolism of microalgae.…”