重楼花叶坏死病毒侵染滇黄精的首次报道

First report of paris mosaic necrosis virus infecting Polygonatum kingianum

滇黄精(Polygonatum kingianum Coll. et Hemsl)为百合科(Liliaceae)黄精属(Polygonatum)多年生草本植物,属于药食两用资源。用于补气养阴、健脾、润肺、益肾,现代药理研究发现具有抗氧化、抗病毒、抗肿瘤等作用。近年滇黄精人工种植发展迅速,病虫害问题凸显。2019-2020年在云南曲靖、昆明滇黄精种植基地调查发现滇黄精表现花叶、褪绿、叶片皱缩、植株矮小等症状(图1-A),该病害田间发病较为普遍,不同地块发生率在5%~15%,一些地块出现集中发病现象。为明确病原种类,本研究利用透射电子显微镜观察、转录组测序、序列分析,对侵染滇黄精的病毒进行鉴定。

Polygonatum kingianum Coll. et Hemsl belongs to polygonatum herb of Liliaceae, which can be used as medicine and food. Recently P. kingianum plants exhibiting mosaic and chlorosis symptoms were found and collected in the plantation base of Qujing and Kunming in Yunnan province. Negative staining electron microscope observation, transcriptome sequencing and RT-PCR detection were used to identify the pathogen of the diseased P. kingianum plants. Filamentous virus particles with a size of 700×13 nm were observed in the sap of diseased leaves under the electron microscope. The genome sequence of the P. kingianum isolate of Paris mosaic necrosis virus(PMNV-PK) obtained by transcriptome sequencing was 9 569 nt in length, and the nucleotide sequence shared 85.68% identities with that of Paris mosaic necrosis virus isolate PMNV-cn. The expected fragments of 1630 bp were amplified from 7 diseased samples of Qujing and Kunming with the potyviruses degenerated primers for 3′-terminal sequences by RT-PCR. Sequence analysis showed that the obtained CP sequences were identical to that from transcriptome sequences and shared 96.68% amino acid sequence identities with PMNV-cn. Phylogenetic analysis based on the full-length nucleotide sequences showed that 3 PMNV isolates were closely related to fritillary virus Y and saffron latent virus. The results indicated the virus pathogen causing the mosaic and chlorosis symptoms of P. kingianum was an isolate of PMNV. This was the first report of PMNV infecting P. kingianum.