中文摘要：

为了评价3种PCR分子检测体系对柑橘黄龙病（citrus huanglongbing，HLB）大田诊断效果，综合比较了常规PCR、巢式PCR和SYBRGreenI荧光定量PCR（SGI—qPCR）方法对柑橘黄龙病菌检测的灵敏度、特异性和准确度等参数，并用SYBRGreenI荧光定量PCR和巢式PCR监测广西柑橘园疑似HLB样品425个，比较了2种检测体系的阳性检出率。基于CQULA04F／CQULA04R引物对的SYBRGreenI荧光定量PCR的灵敏度可达10ag／μL；而巢式PCR灵敏度为100ag／μL，巢式PCR较常规PCR检测灵敏度高10^4倍。疑似样品的HLB病原SYBRGreenI荧光定量PCR和巢式PCR检出率分别为46．6％、40．0％。各检测体系的灵敏性、特异性、符合度依次为SYBRGreenI荧光定量PCR〉巢式PCR〉常规PCR。研究表明，SYBRGreenI荧光定量PCR可作为果园大规模HLB早期诊断和监测的首选，而在缺乏定量检测仪器时，巢式PCR也可用于HLB的检测．但需注意避免空气污染导致的假阳性。

英文摘要：

In order to provide practical detection approach for early diagnosis and dynamic monitoring of citrus huanglongbing （HLB） pathogen. The sensitivity, specificity and accuracy of 3 type PCR approa- ches were compared. Total 425 suspected citrus samples with or without symptom of HLB from plantation of Hepu County, Guangxi were amplified and confirmed by nested-PCR and SYBR Green I -qPCR （ SG I -qPCR）. The effectiveness and the positive rates of the two PCR were evaluated. The results showed that the detection sensitivity of SG I -qPCR for HLB pathogen DNA was 10 ag/μL, while was 100 ag/μL for nested-PCR. Conventional PCR detection sensitivity was 104 times lower than nested-PCR method. Positive rate percent of detection for suspected citrus samples were in 46.6% and 40.0% by SG I -qPCR and nested-PCR, respectively, which indicated that SG I -qPCR was able to provide more accurate diag- noses than nested-PCR. The sensitivity and veracity of conventional PCR, nested-PCR and SG I -qPCR system were enhancing in turn. Practically, SG I -qPCR should be concerned priority selection in large scale early diagnosis and dynamic monitoring in citrus plantation. As the PCR instrument of quantitative detection not available, nested-PCR could be used for better detection of HLB as long as well controllingof the air pollution of amplified procedure, in order to prevent the false positive amplification.