State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China.
Hubei Key Laboratory of Plant Pathology, Huazhong Agricultural University, Wuhan, 430070, China.
ISME J. 2022 Dec;16(12):2763-2774. doi: 10.1038/s41396-022-01310-y. Epub 2022 Aug 31.
Interspecies transmission of viruses is a well-known phenomenon in animals and plants whether via contacts or vectors. In fungi, interspecies transmission between distantly related fungi is often suspected but rarely experimentally documented and may have practical implications. A newly described double-strand RNA (dsRNA) virus found asymptomatic in the phytopathogenic fungus Leptosphaeria biglobosa of cruciferous crops was successfully transmitted to an evolutionarily distant, broad-host range pathogen Botrytis cinerea. Leptosphaeria biglobosa botybirnavirus 1 (LbBV1) was characterized in L. biglobosa strain GZJS-19. Its infection in L. biglobosa was asymptomatic, as no significant differences in radial mycelial growth and pathogenicity were observed between LbBV1-infected and LbBV1-free strains. However, cross-species transmission of LbBV1 from L. biglobosa to infection in B. cinerea resulted in the hypovirulence of the recipient B. cinerea strain t-459-V. The cross-species transmission was succeeded only by inoculation of mixed spores of L. biglobosa and B. cinerea on PDA or on stems of oilseed rape with the efficiency of 4.6% and 18.8%, respectively. To investigate viral cross-species transmission between L. biglobosa and B. cinerea in nature, RNA sequencing was carried out on L. biglobosa and B. cinerea isolates obtained from Brassica samples co-infected by these two pathogens and showed that at least two mycoviruses were detected in both fungal groups. These results indicate that cross-species transmission of mycoviruses may occur frequently in nature and result in the phenotypical changes of newly invaded phytopathogenic fungi. This study also provides new insights for using asymptomatic mycoviruses as biocontrol agent.
病毒在动物和植物中的种间传播是一种众所周知的现象，无论是通过接触还是媒介。在真菌中，种间传播在亲缘关系较远的真菌之间经常被怀疑，但很少有实验记录，并且可能具有实际意义。一种新描述的双链 RNA(dsRNA)病毒在十字花科作物病原菌 Leptosphaeria biglobosa 中无症状，成功地传播到了一种进化上相距甚远、宿主范围广泛的病原体 Botrytis cinerea。Leptosphaeria biglobosa botybirnavirus 1 (LbBV1)在 L. biglobosa 菌株 GZJS-19 中得到了表征。在 L. biglobosa 中的感染是无症状的，因为在 LbBV1 感染和 LbBV1 自由菌株之间没有观察到径向菌丝生长和致病性的显著差异。然而，LbBV1 从 L. biglobosa 到 B. cinerea 的种间传播导致受感染的 B. cinerea 菌株 t-459-V 的弱毒化。种间传播仅通过在 PDA 或油菜茎上接种混合孢子的方式从 L. biglobosa 接种到 B. cinerea 中得以成功，效率分别为 4.6%和 18.8%。为了研究 L. biglobosa 和 B. cinerea 之间病毒的种间传播，对从这两种病原体共同感染的 Brassica 样本中获得的 L. biglobosa 和 B. cinerea 分离物进行了 RNA 测序，结果表明在这两个真菌群体中至少检测到两种真菌病毒。这些结果表明，真菌病毒的种间传播可能在自然界中经常发生，并导致新入侵的植物病原菌真菌的表型变化。本研究还为利用无症状真菌病毒作为生物防治剂提供了新的见解。
