DsRNA-free transmissible hypovirulence associated with formation of intra-hyphal hyphae in Botrytis cinerea

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• 作者：Jian Bo Cao^a ; ^b ; Yu Zhou^a ; Lei Zhang^a ; Jing Zhang^a ; Long Yang^a ; Li Hong Qin^b ; Dao Hong Jiang^a ; Guo Qing Li^a ; ^{guoqingli@mail.hzau.edu.cn} ; Hung-Chang Huang^c
• 关键词：Botrytis cinerea ; Intra-hyphal hyphae ; Oilseed rape ; Transmissible hypovirulence
• 刊名：Fungal Biology
• 出版年：2011
• 出版时间：July 2011
• 年：2011
• 卷：115
• 期：7
• 页码：660-671
• 全文大小：4191 K

文摘

A spontaneous mutant CanBc-3HV and its parental strain CanBc-3 of Botrytis cinerea were investigated in terms of pathogenicity, colony morphology, hypovirulence transmissibility, presence of double-stranded RNA (dsRNA), and formation of intra-hyphal hyphae (IH). Results showed that inoculation of CanBc-3HV on detached leaves of Brassica napus did not produce any visible necrotic lesions (20 ¡ãC, 72 h), whereas inoculation of CanBc-3 caused necrotic leaf lesions. Compared to CanBc-3, CanBc-3HV grew slowly, formed numerous mycelial sectors, sporulated sporadically and failed to produce sclerotia on potato dextrose agar (PDA) (20 ¡ãC, 15 d). Hypovirulence and the abnormal cultural characteristics of CanBc-3HV were transmissible from CanBc-3HV to CanBc-3 in pair cultures on PDA. However, the transmission was unsuccessful from CanBc-3HV to another virulent strain CanBc-2 of B. cinerea. These results suggest that transmission of the hypovirulence and the abnormal cultural characteristics of CanBc-3HV are strain-specific. No dsRNA was detected in mycelia of either CanBc-3HV or CanBc-3, implying that the hypovirulence of CanBc-3HV is caused by a transmissible element (TE) of non-RNA mycoviral origin. Formation of IH through self-infection was observed in CanBc-3HV, CanBc-3T1 (a hypovirulent derivative of CanBc-3 trans-infected by TE in CanBc-3HV), but was not observed in CanBc-3, suggesting that IH formation is associated with the hypovirulence of CanBc-3HV. To our knowledge, this is the first report of dsRNA-free transmissible hypovirulence associated with IH formation in B. cinerea.