Identification and characterization of multiple dsRNases from a lepidopteran insect, the tobacco cutworm, Spodoptera litura (Lepidoptera: Noctuidae)

Yingchuan Peng, Kangxu Wang, Guanheng Zhu, Qunxin Han, Jiasheng Chen, Mohammed Esmail Abdalla Elzaki, Chengwang Sheng, Chunqing Zhao, Subba Reddy Palli, Zhaojun Han

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

Abstract

RNA interference (RNAi) efficiency varies among insects. RNAi is highly efficient and systemic in coleopteran insects but quite variable and inefficient in lepidopteran insects. Degradation of double-stranded RNA (dsRNA) by double-stranded ribonucleases (dsRNases) is thought to contribute to the variability in RNAi efficiency observed among insects. One or two dsRNases involved in dsRNA digestion have been identified in a few insects. To understand the contribution of dsRNases to reduced RNAi efficiency in lepidopteran insects, we searched the transcriptome of Spodoptera litura and identified six genes coding for DNA/RNA non-specific endonucleases. Phylogenetic analysis revealed the evolutionary expansion of dsRNase genes in insects. The mRNA levels of three midgut-specific dsRNases increased during the larval stage, and the highest dsRNA-degrading activity was detected in third-instar larvae. Proteins produced via the expression of three midgut-specific dsRNases, and the widely expressed dsRNase3, in a baculovirus system showed dsRNase activity for four out of five dsRNases tested. In addition, the increase in dsRNA-degrading activity and upregulation of dsRNase1 and 2 in larvae fed on cabbage leaves suggests that the diet of S. litura can influence dsRNase expression, dsRNA stability, and thus probably RNAi efficiency. This is the first report that multiple dsRNases function together in an RNAi-recalcitrant insect. The data included in this paper suggest that multiple dsRNases coded by the S. litura genome might contribute to the lower and variable RNAi efficiency reported in this and other lepidopteran insects.

Original languageEnglish
Pages (from-to)86-95
Number of pages10
JournalPesticide Biochemistry and Physiology
Volume162
DOIs
StatePublished - Jan 2020

Bibliographical note

Publisher Copyright:
© 2019 Elsevier Inc.

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Health, Toxicology and Mutagenesis

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