Liu Yir-Chung, Dynek Jasmin N, Hillman Bradley I, Milgroom Michael G
Department of Plant Pathology, Cornell University, Ithaca, NY 14853, USA.
Mycol Res. 2007 Apr;111(Pt 4):433-42. doi: 10.1016/j.mycres.2006.12.006. Epub 2007 Feb 4.
We surveyed native populations of the chestnut blight fungus, Cryphonectria parasitica, in Japan and China, and C. nitschkei, a sympatric species on chestnut trees in Japan, to learn more about the diversity of hypoviruses and other double-stranded (ds) RNA viruses. In a sample of 472 isolates of C. parasitica and 45 isolates of C. nitschkei from six prefectures in Japan, we found 27 containing one or more dsRNAs. Twelve isolates of C. parasitica and two isolates of C. nitschkei were infected with Cryphonectria hypovirus 1 (CHV-1); four of these 12 C. parasitica isolates also contained other dsRNAs that did not hybridize to CHV-1. In China, only one of 85 C. parasitica isolates was CHV-1-infected; no dsRNAs were detected in the other isolates from China. No other known hypoviruses were found in this study. However, we found two previously undescribed dsRNAs in Japan approximately 9kb in size that did not hybridize to each other or to any known dsRNAs from C. parasitica. We also found three additional groups of dsRNAs, one of which represents the genome of a new member of the virus family Chrysoviridae and was found only in C. nitschkei; the other two dsRNAs were found previously in isolates of C. parasitica from Japan or China. The most significant result of this survey is the discovery of novel dsRNAs that can be characterized in future research.
我们调查了日本和中国的栗疫病菌（Cryphonectria parasitica）以及日本栗树上的同域物种尼氏隐孢壳菌（C. nitschkei）的本地种群，以进一步了解低毒病毒和其他双链（ds）RNA病毒的多样性。在从日本六个县采集的472株栗疫病菌和45株尼氏隐孢壳菌样本中，我们发现27株含有一种或多种dsRNA。12株栗疫病菌和2株尼氏隐孢壳菌感染了栗疫病菌低毒病毒1（CHV-1）；这12株栗疫病菌中的4株还含有与CHV-1不杂交的其他dsRNA。在中国，85株栗疫病菌分离株中只有1株感染了CHV-1；在中国的其他分离株中未检测到dsRNA。本研究未发现其他已知的低毒病毒。然而，我们在日本发现了两种以前未描述的dsRNA，大小约为9kb，它们彼此之间不杂交，也不与栗疫病菌的任何已知dsRNA杂交。我们还发现了另外三组dsRNA，其中一组代表病毒科金黄病毒科一个新成员的基因组，仅在尼氏隐孢壳菌中发现；另外两种dsRNA以前在日本或中国的栗疫病菌分离株中发现。这项调查最重要的结果是发现了可在未来研究中进行表征的新型dsRNA。
