AUTHOR=Zhou Jielong , Wu Peifu , Xiong Zhongping , Liu Naiyong , Zhao Ning , Ji Mei , Qiu Yu , Yang Bin 

TITLE=Chromosome-Level Genome Assembly Reveals Significant Gene Expansion in the Toll and IMD Signaling Pathways of Dendrolimus kikuchii

JOURNAL=Frontiers in Genetics

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2021.728418

DOI=10.3389/fgene.2021.728418

ISSN=1664-8021

ABSTRACT=<p>A high-quality genome is of significant value when seeking to control forest pests such as <italic>Dendrolimus kikuchii</italic>, a destructive member of the order Lepidoptera that is widespread in China. Herein, a high quality, chromosome-level reference genome for <italic>D. kikuchii</italic> based on Nanopore, Pacbio HiFi sequencing and the Hi-C capture system is presented. Overall, a final genome assembly of 705.51 Mb with contig and scaffold N50 values of 20.89 and 24.73 Mb, respectively, was obtained. Of these contigs, 95.89% had unique locations on 29 chromosomes. <italic>In silico</italic> analysis revealed that the genome contained 15,323 protein-coding genes and 63.44% repetitive sequences. Phylogenetic analyses indicated that <italic>D. kikuchii</italic> may diverged from the common ancestor of <italic>Thaumetopoea. Pityocampa</italic>, <italic>Thaumetopoea ni, Heliothis virescens</italic>, <italic>Hyphantria armigera</italic>, <italic>Spodoptera frugiperda</italic>, and <italic>Spodoptera litura</italic> approximately 122.05 million years ago. Many gene families were expanded in the <italic>D. kikuchii</italic> genome, particularly those of the Toll and IMD signaling pathway, which included 10 genes in <italic>peptidoglycan recognition protein</italic>, 19 genes in <italic>MODSP</italic>, and 11 genes in <italic>Toll</italic>. The findings from this study will help to elucidate the mechanisms involved in protection of <italic>D. kikuchii</italic> against foreign substances and pathogens, and may highlight a potential channel to control this pest.</p>