Identification and functional analyses of the CmdsRNase5 and CmdsRNase6 genes in rice leaffolder Cnaphalocrocis medinalis

Mengtiao Mo; Guangming Yang; Juan Du; Ying Zhou; Ashraf Khan; Shangwei Li; Chaoxing Hu

doi:10.1016/j.ijbiomac.2025.140079

Identification and functional analyses of the CmdsRNase5 and CmdsRNase6 genes in rice leaffolder Cnaphalocrocis medinalis

Int J Biol Macromol. 2025 Jan 23:140079. doi: 10.1016/j.ijbiomac.2025.140079. Online ahead of print.

Authors

Mengtiao Mo¹, Guangming Yang², Juan Du¹, Ying Zhou¹, Ashraf Khan¹, Shangwei Li³, Chaoxing Hu⁴

Affiliations

¹ Guizhou Provincial Key Laboratory for Agricultural Pest Management of Mountainous Regions, Institute of Entomology, Guizhou University, Guiyang, Guizhou 550025, China.
² Guizhou Provincial Key Laboratory for Agricultural Pest Management of Mountainous Regions, Institute of Entomology, Guizhou University, Guiyang, Guizhou 550025, China; Guizhou Institute of Biology, Guiyang, Guizhou 550027, China.
³ Guizhou Provincial Key Laboratory for Agricultural Pest Management of Mountainous Regions, Institute of Entomology, Guizhou University, Guiyang, Guizhou 550025, China. Electronic address: swlii@163.com.
⁴ Guizhou Provincial Key Laboratory for Agricultural Pest Management of Mountainous Regions, Institute of Entomology, Guizhou University, Guiyang, Guizhou 550025, China. Electronic address: hcx333@foxmail.com.

PMID: 39863202
DOI: 10.1016/j.ijbiomac.2025.140079

Abstract

RNA interference (RNAi) is a promising method for pest control; however, some studies have showed that the degradation of double-stranded RNA (dsRNA) by dsRNA-degrading nucleases (dsRNases) is one of the factors that may reduce RNAi efficiency in lepidopteran insects. In this study, we cloned two dsRNase genes named CmdsRNase5 and CmdsRNase6 from rice leaffolder Cnaphalocrocis medinalis, a notorious insect pest of rice. Open reading frames (ORFs) of CmdsRNase5 and CmdsRNase6 are 1317 and 1185 bp in length, encoding 438 and 394 amino acids, respectively. These two genes were expressed at the highest level in the third-instar larvae throughout developmental stages and highly expressed in the midgut and hemolymph of C. medinalis. RNAi efficiencies of CmdsRNase5 and CmdsRNase6 were 57.44 % and 63.94 % on day 3, respectively. The RNAi efficiency of a target gene CmCHS (chitin synthase from C. medinalis) was 58.70 % on day 5 and this efficiency was 87.63 % after co-silencing of CmCHS + CmdsRNase5 + CmdsRNase6. The findings suggested that co-silencing of CmdsRNases alongside CmCHS mitigated the degradation of dsCmCHS and enhanced the RNAi efficiency in C. medinalis, leading to phenotypic deformities, increased mortality, and a significant reduction in both egg production and hatching rate. Transcriptome analysis indicated CmdsRNase5 or CmdsRNase6 knockdown affected the expression of many important functional genes, thereby hindering the growth and development of C. medinalis. The concurrent silencing of both CHS and dsRNases provides a novel strategy for RNAi-mediated green control of C. medinalis and other lepidopteran pests.

Keywords: Chitin synthase; Cnaphalocrocis medinalis; Double-stranded RNA-degrading nuclease (dsRNase); RNA interference (RNAi); RNAi efficiency.