烟草立枯病病菌人工诱发病害效果比较初探

Induction effect of tobacco seeding blight inoculated by Rhizoctonia solani artificially

采用人工接种方法,将烟草立枯病病菌菌株TRs-5接种于烟草云烟87的不同部位,观察其发病效果。研究了菌株接种体在不同接种温度和培养时间对发病效果的影响,并比较了其与稻纹枯病病菌菌株RRs08-22-2接种于水稻品种中优679的致病效果。结果表明,菌株TRs-5既能侵染烟草幼苗近地表的茎基部,导致其发病,也能侵染烟草成株苗叶面形成坏死病斑。在温度28℃环境下接种比在20℃的导致发病更严重。用培养2 d的菌丝体接种比培养4 d的导致更大的病斑。在寄主烟草上,菌株TRs-5比菌株RRs08-22-2的致病力强,但在寄主水稻上,菌株TRs-5比菌株RRs08-22-2的致病力弱。初步发现这2个病菌与2个寄主之间存在致病专化现象。

Pathogenic effect at different parts of tobacco plant of variety Yunyan87 caused by inoculation of isolate TRs-5,the fungus pathogen causing tobacco seeding blight,was examined, and impact of different temperature and growth days of inoculum of the fungus was compared. Meanwhile, pathogenic effect on rice variety Zhongyou 679 by isolate TRs-5 and isolate RRs08-22-2, the fungus pathogen causing rice sheath blight, was also studied by method of artificial inoculation.The results showed that isolate TRs-5 possessed infected ability on tobacco both in base stem of small seedlings causing typical symptom, and on leaf blade of adult plants causing necrotic spot. The disease was more serious at 28 ℃ than that at 20 ℃. Disease spot were larger by inoculation with mycelium grown for 2 days than that for 4 days. TRs-5 showed stronger pathogenicity than RRs08-22-2 on host of tobacco, while RRs08-22-2 was stronger than TRs-5 on rice, which indicated pathogenic specialization of TRs-5 and RRs08-22-2 on the two hosts.