应用Nested PCR技术检测柑桔木虱及其寄主九里香的柑桔黄龙病带菌率

Detection of the bearing rate of Liberobacter asiaticum, in Citrus psylla and its host plant Murraya panciculata by Nested PCR

应用PCR及Nested PCR技术检测柑桔木虱及其寄主九里香的结果表明:PCR只可检测最低2头带菌木虱,Nested PCR可检测到单个带菌木虱。100头带菌木虱中,单虫检出率为96％。检测田间重、中等、轻病的柑桔园内的木虱,其带菌率依次为87％、53％和21％。在病芦柑上饲菌不同天数的木虱均能检测出带菌,其饲菌时间最短为1d。城市九里香叶片及在其叶上取食的木虱单虫,均能用Nested PCR检测出病原。饲菌木虱接种九里香及芦柑健苗,在植株尚未表现症状时,常规PCR难检测出病原,但用Nested PCR则能检测到病原,说明九里香不仅是木虱的寄主,而且是黄龙病病原的隐症寄主。

The bearing rates of Liberobacter asiaticum, ihe baclerial palhogen of citrus yellow shoot which is the most destructive citrus disease in China, in the veclor citrus psylla Diaphornia citri Kuwayand and its host plant 'Jiulixiang' Murraya panciculata were delected by PCR and Nested PCR methods. The results showed that at least two psyllid individuals per sample were needed for common PCR to detect the bacteria bearing, while one individual per sample was quite enough for Nested PCR detection, its discovery rate can be up to 96% . By Nested PCR analyses, the bacteria bearing rates of C. psylla from heavy, medium and light infection citrus orchards were determined as 87% ,53% and 21% respectively; all the psyllids having led on diseased ponkan , a local citrus variety, for different days were evidently bacteria bearing, in which the shortest feeding time was one day; and the bacterial pathogen had been found in the leaves of M. panciculata growing inside the city and in single psyllid samples fed on the leaves. When the bacteria bearing psyllids had been inoculated on the healthy seedlings of M. panciculata and ponkan and the disease sysmtom was not yet appeared, the pathogen of this disease can be detected by Nested PCR, but not common PCR. The facts mentioned above indicated that M. panciculata is not only the host plant of C. psylla, but also the cryptic sysmtom host plant of the pathogen of citrus yellow shoot disease.