Nagata T, Inoue-Nagata A K, Smid H M, Goldbach R, Peters D
J Gen Virol. 1999 Feb;80 ( Pt 2):507-515. doi: 10.1099/0022-1317-80-2-507.
The development of tomato spotted wilt tospovirus (TSWV) infection in the midgut and salivary glands of transmitting and non-transmitting thrips, Frankliniella occidentalis, was studied to elucidate tissue tropism and the virus pathway within the body of this vector. Immunohistological techniques used in this study showed that the midgut, foregut and salivary glands were the only organs in which virus accumulated. The first signals of infection, observed as randomly distributed fluorescent granular spots, were found in the epithelial cells of the midgut, mainly restricted to the anterior region. The virus subsequently spread to the circular and longitudinal midgut muscle tissues, a process which occurred late in the larval stage. In the adult stage, the infection occurred in the visceral muscle tissues, covering the whole midgut and foregut, and was abolished in the midgut epithelium. The infection of the salivary glands was first observed 72 h post-acquisition, and simultaneously in the ligaments connecting the midgut with these glands. The salivary glands of transmitting individuals appeared heavily or completely infected, while no or only a low level of infection was found in the glands of non-transmitting individuals. Moreover, the development of an age-dependent midgut barrier against virus infection was observed in second instar larvae and adults. The results show that the establishment of TSWV infection in the various tissues and the potential of transmission seems to be regulated by different barriers and processes related to the metamorphosis of thrips.
为阐明西花蓟马体内的组织嗜性和病毒传播途径，研究了番茄斑萎病毒（TSWV）在传播和非传播西花蓟马中肠和唾液腺中的感染情况。本研究中使用的免疫组织学技术表明，中肠、前肠和唾液腺是病毒积累的唯一器官。感染的最初信号表现为随机分布的荧光颗粒斑点，见于中肠上皮细胞，主要局限于前部区域。病毒随后扩散到中肠的环形和纵形肌肉组织，这一过程发生在幼虫期后期。在成虫期，感染发生在内脏肌肉组织，覆盖整个中肠和前肠，而中肠上皮细胞中的感染消失。在获毒后72小时首次观察到唾液腺感染，同时在连接中肠与这些腺体的韧带中也观察到感染。传播个体的唾液腺似乎受到严重或完全感染，而非传播个体的腺体中未发现感染或仅发现低水平感染。此外，在二龄幼虫和成虫中观察到中肠对病毒感染的年龄依赖性屏障的形成。结果表明，TSWV在不同组织中的感染建立和传播潜力似乎受与蓟马变态相关的不同屏障和过程的调节。
