Department of Biology, Josip Juraj Strossmayer University of Osijek, HR-31000, Osijek, Croatia.
Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia.
Microb Ecol. 2020 Jan;79(1):148-163. doi: 10.1007/s00248-019-01377-9. Epub 2019 May 3.
Transmissible hypovirulence associated with Cryphonectria hypovirus 1 (CHV1) has been used for biological control of chestnut blight, devastating disease of chestnut caused by the fungus Cryphonectria parasitica. The main aims of this study were to provide molecular characterization of CHV1 from Croatia and Slovenia and to reveal its genetic variability, phylogeny, and diversification of populations. Fifty-one CHV1 haplotypes were detected among 54 partially sequenced CHV1 isolates, all belonging to Italian subtype (I). Diversity was mainly generated by point mutations while evidence of recombination was not found. The level of conservation over analyzed parts of ORF-A proteins p29 and p40 varied, but functional sites were highly conserved. Phylogenetic analysis revealed close relatedness and intermixing of Croatian and Slovenian CHV1 populations. Our CHV1 isolates were also related to Swiss and Bosnian hypoviruses supporting previously suggested course of CHV1 invasion in Europe. Overall, this study indicates that phylogeny of CHV1 subtype I in Europe is complex and characterized with frequent point mutations resulting in many closely related variants of the virus. Possible association between variations within CHV1 ORF-A and growth of the hypovirulent fungal isolates is tested and presented.
传染性弱毒现象与 Cryphonectria hypovirus 1（CHV1）相关联，已被用于生物防治栗疫病，栗疫病是由真菌 Cryphonectria parasitica 引起的毁灭性栗疫病。本研究的主要目的是提供来自克罗地亚和斯洛文尼亚的 CHV1 的分子特征，并揭示其遗传变异性、系统发育和种群多样化。在 54 个部分测序的 CHV1 分离株中检测到 51 种 CHV1 单倍型，均属于意大利亚型（I）。多样性主要由点突变产生，而没有发现重组的证据。分析的 ORF-A 蛋白 p29 和 p40 的部分保守性变化，但功能位点高度保守。系统发育分析显示，克罗地亚和斯洛文尼亚的 CHV1 种群密切相关且混合。我们的 CHV1 分离株还与瑞士和波斯尼亚的弱毒病毒有关，支持了 CHV1 在欧洲入侵的先前建议过程。总体而言，本研究表明，欧洲 I 型 CHV1 的系统发育复杂，具有频繁的点突变，导致病毒的许多密切相关变体。还测试和提出了 CHV1 ORF-A 内的变异与弱毒真菌分离株生长之间的可能关联。
