Chromosome-level genome assembly of Chironomus striatipennis Kieffer
provides insights into benthic adaptation and metamorphosis mechanism
- Guo Bingxin
Abstract
Chironomid is the most important macroinvertebrate species in aquatic
ecosystem. Chironomus represents the most important genus of the
Chironomidae. However, the species of this genus lack a high-quality
assembled genome. Here, a high-quality chromosome-level assembled genome
of Chironomus striatipennis which is an important model organism in
aquatic ecological detection and toxicological application has been
reported. The assembled genome size of C. striatipennis was 181.84 Mb,
with a scaffold N50 value of 54.13 Mb. Furthermore, the molecular
mechanism of adaptive evolution of Chironomid to benthic environment was
elucidated by combining transcriptome data of different stages. The
complete metabolic pathway of Hemoglobin was clarified in C.
striatipennis for the first time to suggests the regulatory mechanism
underlying its adaptation to benthic living. The expansions of CYP450s
gene family related to detoxification explain its tolerance to the harsh
environment. The key gene family, JHAMT, involved in biosynthesis of
juvenile hormone are substantially expanded. The expansion of JHAMT
genes and the regular regulation of juvenile hormone and ecdysone
explain the developmental plasticity of C. striatipennis. In this study,
it was also found that C. striatipennis is more dependent on JNK signal
pathway induced metamorphosis than Drosophila melanogaster. This study
provides some views into genetic basis of tolerance and adaptation of C.
striatipennis to harsh benthic environments and lays a part of the
foundation for the adaptive evolution of benthic animals.