水稻黑条矮缩病毒在灰飞虱消化系统的侵染和扩散过程

 水稻黑条矮缩病毒 (Rice black streaked dwarf virus, RBSDV) 由介体灰飞虱(Laodelphax striatellus Fallén)以持久增殖型方式传播, 其编码的P9 1蛋白是形成病毒复制和子代病毒粒体装配的场所—病毒原质(viroplasm)的组分之一。为了明确RBSDV在介体昆虫体内的侵染循回过程, 本研究通过原核表达的P9 1蛋白免疫注射兔子制备P9 1抗体, 应用免疫荧光标记技术研究P9 1在饲毒后不同时期的介体灰飞虱体内的定位。共聚焦显微镜观察到饲毒后3 d, P9 1出现在介体中肠的少数上皮细胞内;饲毒后6 d, 在中肠外表的肌肉细胞分布有P9 1;饲毒后10 d, P9 1分布于中肠和后肠表面的肌肉, 同时在唾液腺也能观察到P9 1的存在。结果表明RBSDV在介体灰飞虱体内首先侵染中肠上皮细胞并复制, 随后扩散到中肠表面的肌肉细胞, 并通过环肌和纵肌扩散到中肠和后肠, 最后扩散到唾液腺。本研究首次直观地阐述了RBSDV在灰飞虱消化系统的侵染和扩散过程, 为有效阻断灰飞虱携带并传播病毒奠定基础。

Infection and spread of Rice black streaked dwarf virus in the digestive system of its insect vector small brown planthopper

Rice black streaked dwarf virus (RBSDV), a fijivirus, is transmitted by small brown planthopper (SBPH) in persistent propagative manner. P9 1 encoded by segment 9 is the minimal viral factor required for viroplasm formation and virus replication during RBSDV infection. In order to elucidate the infection route of RBSDV within its insect vector SBPH after viral acquisition, the antibodies against P9 1was prepared. Then, the distribution of P9 1 in the digestive system of SBPHs after ingestion of RBSDV was investigated by immunofluorescence microscopy with antibodies agianst P9 1 conjugated to FITC directly. At 3 days post acqurie virus (p.a.v.), P9 1 was first detected in the epithelial cells of the midgut. At 6 days p.a.v., P9 1 proceeded to the visceral muscles surrounding the midgut epithelial cells; then distributed the visceral muscles of the midgut and hindgut. At 10 days p.a.v., P9 1 distributed throughout in the salivary glands. These results indicated that RBSDV first infected in the midgut epithelium, then proceeded to the visceral muscles surrounding the midgut and hindgut, and finally accumulated into the salivary glands. This is the first report about the infection and spread of RBSDV in its insect vector SBPH, which could give support to develop effective measures for blocking the transmission of RBSDV by SBPH vector.