Co-Silencing of the Voltage-Gated Calcium Channel β Subunit and High-Voltage Activated α1 Subunit by dsRNA Soaking Resulted in Enhanced Defects in Locomotion, Stylet Thrusting, Chemotaxis, Protein Secretion, and Reproduction in Ditylenchus destructor

The voltage-gated calcium channel (VGCC) beta subunit (Ca-v beta) protein is a kind of cytosolic auxiliary subunit that plays an important role in regulating the surface expression and gating characteristics of high-voltage-activated (HVA) calcium channels. Ditylenchus destructor is an important plant-parasitic nematode. In the present study, the putative Ca-v beta subunit gene of D. destructor, namely, DdCa(v)beta, was subjected to molecular characterization. In situ hybridization assays showed that DdCa(v)beta was expressed in all nematode tissues. Transcriptional analyses showed that DdCa(v)beta was expressed during each developmental stage of D. destructor, and the highest expression level was recorded in the third-stage juveniles. The crucial role of DdCa(v)beta was verified by dsRNA soaking-mediated RNA interference (RNAi). Silencing of DdCa(v)beta or HVA Ca-v alpha(1) alone and co-silencing of the DdCa(v)beta and HVA Ca-v alpha(1) genes resulted in defective locomotion, stylet thrusting, chemotaxis, protein secretion and reproduction in D. destructor. Co-silencing of the HVA Ca-v alpha(1) and Ca-v beta subunits showed stronger interference effects than single-gene silencing. This study provides insights for further study of VGCCs in plant-parasitic nematodes.