枣缩果病互隔链格孢菌的潜在寄主研究

Potential Hosts of Alternaria alternata, the Pathogen of Jujube Shrunken-fruit Disease

[目的]发掘枣缩果病菌可能存在的潜在寄主,为探究枣缩果病的初侵染来源寻找突破口。[方法]用gfp标记的枣缩果病初侵染互隔链格孢菌CN193菌株(CN193::gfp)的孢子悬浮液,以刺伤和无伤两种方式,接种选自枣园周围栽植的番茄、烟草、苹果、梨、毛白杨和加杨,然后,将发病部位病健交界处的组织置于加有10μg·mL^(-1)潮霉素B的PDA培养基上培养,荧光显微镜观察发病组织和从各寄主上分离获得的病菌菌丝。[结果]刺伤接种7 d后,除烟草外,其他刺伤的材料均发病,发病率依次为番茄果实45.8%、苹果果实79.2%、苹果叶片75.0%、梨果实56.3%、梨叶片52.1%、毛白杨叶片66.7%和加杨叶片54.2%;无伤处理的仅番茄发病,其他材料和对照组均未发病。番茄病部组织的荧光清晰可辨;在发病的番茄果实、苹果果实和叶片、梨果实和叶片、毛白杨和加杨离体叶片病部组织分离后长出的菌丝中,均可以观察到明显的荧光。[结论]枣缩果病菌能成功侵染番茄、苹果、梨、毛白杨和加杨,并可使各寄主植物产生与番茄黑斑病、苹果褐纹病、梨黑斑病和杨树叶枯病相同的症状,推断番茄、苹果、梨、毛白杨和加杨为枣缩果病菌的潜在寄主,扩大了枣缩果病菌初侵染来源的范围,为进一步开展枣缩果病的防治拓宽了渠道。

[Objective] To explore the potential hosts of Alternaria alternata, the pathogen of jujube shrunken-fruit disease (JSFD) and the sources of primary infection for JSFD.[Method] The spore suspension of a gfp-tagged strain of A. alternata CN193, designated as CN193::gfp, were inoculated with and without stab wound to the fruits and/or leaves of Lycopersivon esculentum, Nicotiana tabacum, Malus domestica cv. Red Fuji, Pyrus bretschneideri, Populus tomentosa and Populus canadensis from the surrounding area of jujube plantation. The marginal tissues with healthy and diseased parts were transferred onto potato dextrose agar media with supplement of 10 μg·mL^-1 hygromycin B, and the infected tissues and the hyphae isolated from each of the inoculated material were observed under fluorescence microscope.[Result] All the inoculated materials with stabbing wound, except for N. tabacum plant, developed diseased symptoms after 7 days of inoculation. The disease rates of all the above materials inoculated with spore suspension were 45.8% of L. esculentum fruits, 79.2% of apple fruits, 75.0% of M. domestica cv. Red Fuji leaves, 56.3% of Pyrus bretschneideri fruits, 52.1% of Pyrus bretschneideri leaves, 66.7% of Populus tomentosa leaves and 54.2% of Populus canadensis leaves. Through non-wounded inoculation only L. esculentum fruits showed the symptoms, and all the other treated materials and the controls did not present any visible disease development. Strong fluorescence could be observed in the infected tissues of L. esculentum fruits, and in the hyphae of isolates from all infected materials, including the fruits of L. esculentum, the fruits and leaves of M. domestica cv. Red Fuji, the fruits and leaves of Pyrus bretschneideri, and the leaves of Populus tomentosa and Populus canadensis.[Conclusion] The pathogen of JSFD is able to successfully infect the L. esculentum, M. domestica cv. Red Fuji, Pyrus bretschneideri, Populus tomentosa and Populus canadensis, and it could cause the same symptoms as tomato melasma, apple brown spot, pear black spot, and poplar leaf blight, inferring that L. esculentum, M. domestica cv. Red Fuji, Pyrus bretschneideri, Populus tomentosa and Populus canadensis are the potential hosts of JSFD.