Abstract:

【Objective】 In order to elucidate the function of cathepsin B gene from Radopholus similis and provide a scientific basis for the further research on this cathepsin B gene of plant-parasitic nematodes, and also for developing new control strategies, the RNAi effect of cathepsin B gene on reproduction of R. similis was studied. 【Method】 Cathepsin B gene of R. similis (Rs-cb-1) was cloned from R. similis by designed primers and used as the target gene for RNA silencing. The specific double-stranded RNA (dsRNA) was synthesized by using plasmid DNA containing target gene as template. The nematodes of R. similis were soaked with dsRNA of Rs-cb-1 and RNA interference (RNAi) effects were evaluated by examining the reproduction of R. similis on carrot discs and detecting the gene transcription by RT-PCR. 【Result】 A significant difference in reproduction factors was observed in treatments with different Rs-cb-1 dsRNA soaking time. The average reproduction factor of R. similis on carrot discs was 165,93,54,53 after dsRNA soaked for 12,24,48, 72 h,respectively. The reproduction factors of those treatments without Rs-cb-1dsRNA soaking were greater than 420. RT-PCR revealed that the transcription of target gene was significantly degenerated after 12 h Rs-cb-1 dsRNA soaking. After soaked for 24 h, the transcription was decreased more with only a weak band appeared in electrophoresis gel. No transcription of Rs-cb-1 was observed after 48 h and 72 h Rs-cb-1 dsRNA soaking. 【Conclusion】 The function of Rs-cb-1 is probably related to the reproduction ability of R. similis Rs-cb-1 dsRNA and soaking inhibited the transcription of cathepsin B gene of R. similis, which may further affected the reproduction of R. similis. The RNAi efficiency of Rs-cb-1 was different in Rs-cb-1 dsRNA soaking times, 48 h dsRNA soaking may produce the best silencing effect on target gene.

Key words: Radopholus similis')">Radopholus similis, cathepsin B gene, RNAi, reproduction