组织蛋白酶D有助于SRBSDV在白背飞虱体内复制

Cathepsin D contributes to SRBSDV replication in white-backed planthopper

在白背飞虱(Sogatella furcifera)获毒过程中,南方水稻黑条矮缩病毒(Southern rice black streaked dwarf virus,SRBSDV)与细胞膜上受体结合,借助网格蛋白依赖型内吞作用进入宿主细胞。组织蛋白酶D(Cathepsin D,CathD)是一种天冬氨酸蛋白酶,参与细胞内体/溶酶体内蛋白降解和病毒释放进入细胞质过程,但CathD在SRBSDV侵染其介体白背飞虱时是否发挥作用目前尚不明确。通过RNA干扰(RNA interference,RNAi)沉默白背飞虱体内CathD基因的表达,发现沉默表达CathD基因的白背飞虱在饲喂SRBSDV后的存活率与对照组白背飞虱相比无明显差异,但会降低白背飞虱的带毒比率和带毒量;在果蝇细胞中敲低CathD同源基因的表达并感染果蝇C病毒(Drosophila C virus,DCV),细胞内DCV的复制水平与对照组相比也有明显下调。研究结果提示CathD可能通过一种保守的机制协助病毒在昆虫细胞内增殖,可以作为防控SRBSDV病害的潜在靶标分子。

When the white-backed planthopper(Sogatella furcifera)acquires Southern rice black streaked dwarf virus(SRBSDV)by feeding on SRBSDV-infected rice,the SRBSDV binds to receptors on the cell membrane and enters the host cell via clathrin-dependent endocytosis.Cathepsin D(CathD)is an aspartic protease,which is involved in the process of endosome/lysosomal protein degradation and viral release into the cytoplasm.However,it is unclear whether CathD plays a role in SRBSDV infection of white backed planthopper.RNA interference(RNAi)was used to silence the expression of CathD gene in the white-backed planthopper.The results showed that knocking down the mRNA expression level of CathD in the white-backed planthopper and subsequently SRBSDV feeding did not affect the survival rate of the white-backed planthopper,however,the viral carrier rate and viral quantity in the white-backed planthoppers were decreased.Meanwhile,knockdown the expression of the homologous CathD gene in Drosophila cells decreased DCV replication significantly compared with that of the control group.The results demonstrated that CathD may assist virus proliferation and replication in insects using a conserved mechanism,suggesting that CathD might be a potential target protein for the prevention and control of SRBSDV disease.