Attenuation of virulence in Sclerotinia homoeocarpa during storage is Associated with latent infection by Ophiostoma mitovirus 3a
Attenuation of virulence in Sclerotinia homoeocarpa during storage is Associated with latent infection by Ophiostoma mitovirus 3a
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DOI：
10.1007/s10658-005-8913-3
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发表时间：
2006-02-01
影响因子：
1.8
通讯作者：
Boland, GJ
中科院分区：
文献类型：
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作者：
Deng, F;Boland, GJ
与低毒力相关的有丝分裂病毒Ophiostoma mitVirus 3a(OMV3a)已被证明以潜伏感染的形式在加拿大东部的同种核盘菌种群中广泛存在。OMV3a的潜伏感染与明显的表型无关，也不会显著降低病原菌的生长和毒力。在本研究中，我们发现潜伏感染OMV3a的同果链霉菌在4℃下储存后可以转变为弱毒力分离物，并且这种毒力的减弱与OMV3a病毒浓度的增加有关。反复观察表明，在储存21个月后，高达29.8%的潜伏感染分离物转变为弱毒力分离物。OMV3a dsRNA从潜伏感染菌株向无病毒菌株的传播导致了受体菌株的潜伏感染，表明OMV3a潜伏感染与真菌宿主的遗传差异无关。对OMV3a病毒潜伏感染和弱毒力分离株的RNA基因组进行了测序和比较。这两个RNA都含有一个由726个氨基酸组成的开放阅读框架，具有典型的依赖RNA的RNA聚合酶(RdRp)的保守基序。两株OMV3aRNA的核苷酸同源性为95.1%，氨基酸同源性为94.6%。OMV3a病毒潜伏侵染产生的低毒力可能为提高美元现货管理中低毒力的生物防治效果提供新的策略。
The hypovirulence-associated mitovirus, Ophiostoma mitovirus 3a (OMV3a), has been shown to be widespread in eastern Canadian populations of Sclerotinia homoeocarpa in the form of latent infection. Latent infection by OMV3a was not associated with an apparent phenotype and did not significantly reduce the growth and virulence of the pathogen. In the present study, we found that isolates of S. homoeocarpa latently infected by OMV3a can change to hypovirulent isolates after storage at 4 degrees C, and that this attenuation of virulence was associated with increased concentration of the OMV3a virus. Recurrent observations revealed that up to 29.8% of latently infected isolates changed to hypovirulent isolates after 21 months of storage. Transmission of OMV3a dsRNA from latently infected isolates to virus-free isolates resulted in latent infection of the recipient isolates, indicating that latent infection by OMV3a was not associated with genetic differences in the fungal host. The RNA genomes of the OMV3a virus in an isogenic pair of latently infected and hypovirulent isolates were sequenced and compared. Each of the two RNAs contained an open reading frame of 726 amino acids with conserved motifs typical of RNA-dependent RNA polymerase (RdRp). The OMV3a RNA sequences in these two isolates share 95.1% nucleotide and 94.6% amino acid sequence identities. The development of hypovirulence from latent infection by OMV3a virus may provide new strategies to improve the biological control efficacy of hypovirulence in dollar spot management.