The genomes of two parasitic wasps that parasitize the diamondback moth

Min Shi,Jiangyan Zhu,Qijuan Gu,Jiani Zou,Jianhua Huang,Rongmin Hu,Michael R Strand,Xiaoxiao Hu,Jian Yang,Zhizhi Wang,Shu‐Jun Wei ,Francesco Pennacchio,Xi-Qian Ye ,Hongqing Xie,Yuan Yao,Yuenan Zhou,Fĕi Li ,Chuanlin Yin,Dan Guo ,Yanping Wang,Zehua Wang,Le-Qing Zhan ,Xue‐Xin Chen

doi:10.1186/s12864-019-6266-0

Abstract

BackgroundParasitic insects are well-known biological control agents for arthropod pests worldwide. They are capable of regulating their host’s physiology, development and behaviour. However, many of the molecular mechanisms involved in host-parasitoid interaction remain unknown.ResultsWe sequenced the genomes of two parasitic wasps (Cotesia vestalis, and Diadromus collaris) that parasitize the diamondback moth Plutella xylostella using Illumina and Pacbio sequencing platforms. Genome assembly using SOAPdenovo produced a 178 Mb draft genome for C. vestalis and a 399 Mb draft genome for D. collaris. A total set that contained 11,278 and 15,328 protein-coding genes for C. vestalis and D. collaris, respectively, were predicted using evidence (homology-based and transcriptome-based) and de novo prediction methodology. Phylogenetic analysis showed that the braconid C. vestalis and the ichneumonid D. collaris diverged approximately 124 million years ago. These two wasps exhibit gene gains and losses that in some cases reflect their shared life history as parasitic wasps and in other cases are unique to particular species. Gene families with functions in development, nutrient acquisition from hosts, and metabolism have expanded in each wasp species, while genes required for biosynthesis of some amino acids and steroids have been lost, since these nutrients can be directly obtained from the host. Both wasp species encode a relative higher number of neprilysins (NEPs) thus far reported in arthropod genomes while several genes encoding immune-related proteins and detoxification enzymes were lost in both wasp genomes.ConclusionsWe present the annotated genome sequence of two parasitic wasps C. vestalis and D. collaris, which parasitize a common host, the diamondback moth, P. xylostella. These data will provide a fundamental source for studying the mechanism of host control and will be used in parasitoid comparative genomics to study the origin and diversification of the parasitic lifestyle.

Highlights

Parasitic insects are well-known biological control agents for arthropod pests worldwide
Genome assembly and gene information The whole genome sequencing was performed by combining Illumina Solexa sequencing based on HiSeq 2000 platform (Illumina, San Diego, CA, USA) and the LongRead Single Molecule Real-Time (SMRT) sequencing based on PacBio Sequel platform (Pacific Biosciences, Menlo Park, CA, USA) in consideration of cost and the low heterozygosity of wasp genome [22, 23]
25.55 Gb (127.78×) from C. vestalis and 49.19 Gb (120.86×) from D. collaris were assembled using SOAPdenovo V2.04 [24] (Additional file 1: Table S2). These data were further assembled into a 178 Mb draft genome for C. vestalis and a 399 Mb draft genome for D. collaris, which were consistent with genome size estimates generated by k-mer analysis (Table 1; Additional file 1: Figure S1)

Summary

Introduction

Parasitic insects are well-known biological control agents for arthropod pests worldwide. They are capable of regulating their host’s physiology, development and behaviour. Most species feed on nectar, while larvae feed as parasites on other arthropods. Parasitic wasps usually produce a number of virulence factors following oviposition that benefit offspring by altering the growth, development and immune defenses of hosts. The sources of these virulence factors include venom [8], symbiotic polydnaviruses (PDVs) [9,10,11,12], and teratocytes [13]

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Results

Conclusion