Faculty of Agriculture, Iwate University, Ueda 3-chome 18-8, Morioka, 020-8550, Japan.
Agr-innovation Center, Iwate University, Ueda 3-chome 18-8, Morioka, 020-8550, Japan.
Arch Virol. 2020 Dec;165(12):2807-2815. doi: 10.1007/s00705-020-04818-w. Epub 2020 Sep 29.
Nicotiana benthamiana plants became infected with blueberry latent spherical virus (BLSV) after pollination with pollen grains produced by BLSV-infected N. benthamiana plants. Interestingly, pollen grains produced by BLSV-infected Vaccinium corymbosum (blueberry), Nicotiana alata, and Petunia × hybrida (petunia) plants also transmitted the virus to healthy N. benthamiana plants after pollination. As seen using aniline blue staining and fluorescence microscopy, pollen grains from BLSV-infected blueberry, N. alata, and petunia plants germinated on stigmas of N. benthamiana, and the pollen tubes penetrated the stigmas in a manner similar to that of N. benthamiana pollen grains on N. benthamiana stigmas. Whole-mount in situ hybridization and chromogenic in situ hybridization analysis showed that infected blueberry and N. benthamiana pollen grains germinated on N. benthamiana stigmas, and virus-containing pollen tubes penetrated the stigmas. Tissue blot hybridization analysis revealed that the initial infection sites were the N. benthamiana stigmas pollinated with infected pollen grains from blueberry and N. benthamiana. In addition, the virus spread from the initial infection sites to the phloem in the stigma and style. Taken together, we suggest that penetrating pollen tubes that harbored the virus results in infection foci in the stigma, and the virus then moves to the vascular tissues in the stigma and style and eventually establishes systemic infection.
在授粉后，感染蓝莓潜隐病毒（BLSV）的烟草原生质体植株被感染。有趣的是，授粉后，感染 BLSV 的蓝莓、矮牵牛和矮牵牛花粉粒也能将病毒传播给健康的烟草原生质体植株。通过苯胺蓝染色和荧光显微镜观察，发现来自感染蓝莓、矮牵牛和矮牵牛的花粉粒在烟草原生质体柱头上萌发，花粉管以类似于烟草原生质体花粉粒在烟草原生质体柱头上的方式穿透柱头。整体原位杂交和显色原位杂交分析表明，感染的蓝莓和烟草原生质体花粉粒在烟草原生质体柱头上萌发，含病毒的花粉管穿透柱头。组织印迹杂交分析显示，最初的感染部位是用感染的蓝莓和烟草原生质体花粉粒授粉的烟草原生质体柱头。此外，病毒从最初的感染部位传播到柱头和花柱中的韧皮部。综上所述，我们认为携带病毒的穿透花粉管会在柱头上形成感染焦点，然后病毒移动到柱头和花柱的维管束组织中，并最终建立系统性感染。
