番茄细菌性溃疡病苗期接种新方法的研究

 在剪叶、浸根和针刺等细菌病害传统接种方法基础上设计了打顶接种新方法;以番茄细菌性溃疡病菌中国菌株和美国菌株借助打顶法接种佳粉10、合作908和华南红宝石3个国内主栽番茄品种2~3片真叶期幼苗,在昼夜最低、最高温度15~18℃、32~35℃和相对湿度为30%~60%的温室条件下,打顶法接种番茄幼苗后溃疡病发病率为87.5%~100.0%,病情指数随接种菌悬液浓度提高而增大,达到23.96~82.29,3个供试品种之间表现稳定一致;剪叶、浸根和针刺接种方法的发病率普遍在40%以下,病情指数在20以下,3个供试品种之间未表现明显差异;进一步研究显示,使用选择性培养基mSCM能够从打顶法接种后的发病植株上获得培养性状与原接种体一致的分离物,专化性免疫凝聚试剂盒检测到特定的测试线,PCR扩增到614bp的特异性条带,证实该分离物为番茄细菌性溃疡病菌,发病植株为接种体侵染所致。该研究结果表明,打顶接种方法比剪叶法、针刺法和浸根法更适合用于番茄溃疡病菌的致病性测定和评价不同番茄品种苗期的抗病性,具有应用价值。

Study on a new inoculating method for bacterial canker of tomato seedlings caused by Clavibacter michiganensis subsp. michiganensis

Top pruning, a new inoculating method of bacterial canker of tomato, was developed based on the traditional methods including leaf shearing, root soaking and needle penetrating in this study. Tomato seedlings of three staple tomato cultivars (Jiafen 10, Hezuo 908 and Huanan Hongbaoshi) with 2-3 true leaf and two representative strains of C. m. subsp. michiganensis (Cmm) from China and United States, were used for the pathogenicity test. Under the green house condition with daily min. and max. temperature 15-18℃, 32-35℃ respectively, and 30%-60% RH, top pruning engendered the typical bacterial canker symptoms on 87.5%-100.0%. The disease index stably increased up to 23.96-82.29 in three experimental cultivars con-sistently with the concentration of inocula. On the other hand, disease rates yielded by leaf shearing, root soaking, and needle penetrating were lower than 40%, and their disease index lower than 20 without significantly difference between the above cultivars. With a selective medium mSCM, isolates obtained from the infected tomato plants were identical in culture characteristic as the inocula. With ImmunoStrip and polymerase chain reaction, the isolates were identified as Cmm. These results indicate that top pruning, as a convenient and efficient inoculation method, is applicable for further evaluating the resistance of tomato seedlings to bacterial canker and chemical control effect to this disease.