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. Laodelphax striatellus 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 CDA genes were identified based on SBPH genomic data and were classified into groups I and III based on a phylogenetic analysis. The expression of LsCDA1 and LsCDA2 in RSV-infected SBPH was increased by 282% and 159%, respectively, relative to the non-infected SBPH control. Additionally, RSV enhanced the expression of LsCDA1 (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 LsCDA1 expression decreased viral loads in RSV-infected SBPH and its ovaries by 66% and 72% relative to the dsGFP control. Silencing LsCDA1 significantly decreased VgR 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 VgR expression, which offers a novel strategy for controlling both RSV and SBPH by targeting LsCDA1.