Novel Partitivirus Enhances Virulence of and Causes Aberrant Gene Expression in Talaromyces marneffei.
Novel Partitivirus Enhances Virulence of and Causes Aberrant Gene Expression in Talaromyces marneffei.
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DOI：
10.1128/mbio.00947-18
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发表时间：
2018-06-12
期刊：
影响因子：
6.4
通讯作者：
Woo PCY
中科院分区：
文献类型：
--
作者：
Lau SKP;Lo GCS;Chow FWN;Fan RYY;Cai JJ;Yuen KY;Woo PCY
马尔尼菲Talaromycesmarneffei是引起东南亚地区系统性真菌病的最重要的热二型真菌。我们报告了一种新的partitivirus，Talaromyces marneffei partitivirus-1（TmPV 1）的发现。在55株马尔尼菲弓形虫临床分离株中，有7株（12.7%）检出TmPV 1。7株TmPV 1分离株的全基因组测序结果显示，TmPV 1分离株均含有两个双链RNA（dsRNA）片段，分别编码RNA依赖的RNA聚合酶（RdRp）和衣壳蛋白。系统发育分析表明，TmPV 1在γ病毒属成员中属于一个独立的分支。透射电子显微镜证实，在TmPV 1感染的马尔尼菲锥虫中存在直径为30至45 nm的等轴无包膜病毒颗粒，与partitiviruses相容。定量逆转录-PCR（qRT-PCR）显示马尔尼菲毛癣菌酵母相的TmPV 1病毒载量高于菌丝相。用纯化的TmPV 1进行原生质体转染，成功地感染了两个脱毒菌株PM 1和PM 41。感染TmPV 1的马尔尼菲毛癣菌感染小鼠的存活时间显著缩短（P < 0.0001），器官真菌负荷显著高于无TmPV 1的同基因分离株感染小鼠。转录组学分析表明，TmPV 1导致马尔尼菲锥虫中各种基因的异常表达，上调潜在的毒力因子和抑制RNA干扰（RNAi）相关基因。这是第一次报告的真菌病毒在热二型真菌。需要进一步的研究来确定TmPV 1增强马尔尼菲毛癣菌在小鼠中毒力的机制以及RNA干扰相关基因在马尔尼菲毛癣菌抗病毒防御中的潜在作用。马尔尼菲篮状菌（Talaromyces marneffei）是东南亚最重要的热二型真菌，可引起HIV感染和免疫功能低下患者高度致命的全身性青霉病。我们在7株马尔尼菲毛癣菌临床分离株中发现了一种新型真菌病毒TmPV 1。TmPV 1属于部分病毒科的γ部分病毒属。我们发现，TmPV 1增强了马尔尼菲锥虫在小鼠中的毒力，与无病毒的同基因分离株相比，TmPV 1感染的马尔尼菲锥虫分离株攻击小鼠的存活时间缩短，器官中的真菌负荷更高。转录组学分析表明，TmPV 1改变了参与马尔尼菲锥虫各种细胞过程的基因的表达，上调了潜在的毒力因子，抑制了可能参与抗病毒防御的RNAi机制。这是第一次在热二型真菌中发现真菌病毒。本研究结果提供了深入了解真菌病毒-真菌相互作用和致病热二型真菌。
Talaromyces marneffei is the most important thermal dimorphic fungus causing systemic mycosis in Southeast Asia. We report the discovery of a novel partitivirus, Talaromyces marneffei partitivirus-1 (TmPV1). TmPV1 was detected in 7 (12.7%) of 55 clinical T. marneffei isolates. Complete genome sequencing of the seven TmPV1 isolates revealed two double-stranded RNA (dsRNA) segments encoding RNA-dependent RNA polymerase (RdRp) and capsid protein, respectively. Phylogenetic analysis showed that TmPV1 occupied a distinct clade among the members of the genus Gammapartitivirus. Transmission electron microscopy confirmed the presence of isometric, nonenveloped viral particles of 30 to 45 nm in diameter, compatible with partitiviruses, in TmPV1-infected T. marneffei. Quantitative reverse transcription-PCR (qRT-PCR) demonstrated higher viral load of TmPV1 in the yeast phase than in the mycelial phase of T. marneffei. Two virus-free isolates, PM1 and PM41, were successfully infected by purified TmPV1 using protoplast transfection. Mice challenged with TmPV1-infected T. marneffei isolates showed significantly shortened survival time (P < 0.0001) and higher fungal burden in organs than mice challenged with isogenic TmPV1-free isolates. Transcriptomic analysis showed that TmPV1 causes aberrant expression of various genes in T. marneffei, with upregulation of potential virulence factors and suppression of RNA interference (RNAi)-related genes. This is the first report of a mycovirus in a thermally dimorphic fungus. Further studies are required to ascertain the mechanism whereby TmPV1 enhances the virulence of T. marneffei in mice and the potential role of RNAi-related genes in antiviral defense in T. marneffei. Talaromyces marneffei (formerly Penicillium marneffei) is the most important thermal dimorphic fungus in Southeast Asia, causing highly fatal systemic penicilliosis in HIV-infected and immunocompromised patients. We discovered a novel mycovirus, TmPV1, in seven clinical isolates of T. marneffei. TmPV1 belongs to the genus Gammapartitivirus of the family Partitiviridae. We showed that TmPV1 enhanced the virulence of T. marneffei in mice, with shortened survival time and higher fungal burden in the organs of mice challenged with TmPV1-infected T. marneffei isolates than in those of mice challenged with virus-free isogenic isolates. Transcriptomics analysis showed that TmPV1 altered the expression of genes involved in various cellular processes in T. marneffei, with upregulation of potential virulence factors and suppression of RNAi machinery which may be involved in antiviral defense. This is the first report of a mycovirus in a thermal dimorphic fungus. The present results offer insights into mycovirus-fungus interactions and pathogenesis of thermal dimorphic fungi.