Chitin Deacetylase Gene Family Positively Regulates the Accumulation of Rice Stripe Virus in Laodelphax striatellus Fallén (Hemiptera: Delphacidae) Ovaries

Chitin deacetylase modifies chitin and has critical functions in the growth and development of insects; however, whether it has other roles is unclear. <i>Laodelphax striatellus</i> not only directly feeds on the phloem sap of rice but also transmits RSV, leading to significant losses in rice production. In this study, four <i>CDA</i> genes were identified based on SBPH genomic data and were classified into groups I and III based on a phylogenetic analysis. The expression of <i>LsCDA1</i> and <i>LsCDA2</i> in RSV-infected SBPH was increased by 282% and 159%, respectively, relative to the non-infected SBPH control. Additionally, RSV enhanced the expression of <i>LsCDA1</i> (increased by 194%) in the ovaries. Yeast two-hybrid and glutathione-S-transferase pull-down assays demonstrated the interaction between LsCDA1 and RSV proteins NP and NS2. Furthermore, the knockdown of <i>LsCDA1</i> expression decreased viral loads in RSV-infected SBPH and its ovaries by 66% and 72% relative to the dsGFP control. Silencing <i>LsCDA1</i> significantly decreased <i>VgR</i> expression in SBPH and its ovaries and reduced fecundity. These results indicate that LsCDA1 positively regulates RSV accumulation in the ovaries and SBPH reproduction by modulating <i>VgR</i> expression, which offers a novel strategy for controlling both RSV and SBPH by targeting LsCDA1.