Detection Of Citrus Huanglongbing Pathogen In Hunan Province And Cloning

Citrus Huanglongbing caused by candidates Liberibacter is one of the most severe diseases. After citrus trees are infected, yield and quality are greatly affected. Area bordering Guangdong and Guangxi Provinces, is accidental spread district citrus Huanglongbing. In recent years, with global temperature going up and citrus psylla campaign scope enlarging, citrus Huanglongbing has become a potential threat. In a few citrus producing districts, the suspected symptom of citrus Huanglongbing already raised, some destroyed orchards were even found. To adopt effective control measure in time and to stop pathogen spreading, more understanding citrus Huanglongbing occurring condition and spreading channel is necessary. This research has been conducted during April 2005 to March 2006. 48 samples have been detected by PCR method and IR (iodine reaction) fast detection. Meanwhile PCR cloning and sequencing measurement were carried out. The results are as follows:1. Based on other studies, this research improved citrus Huanglongbing PCR detection technique and has established an accurate, fast, and sensitive method for citrus Huanglongbing PCR detection system. Taking the bark of summer shoot as material, DNA is comparatively stable, PCR detection is easier and more accurace. Primers of OL1/OL2 have good stability and high sensitivity for citrus Huanglongbing PCR detection.2. New column designed for purifying PCR, which is simple and very convenient. PCR product can be purified and retrieved well. Purified PCR product has a good resolution with pTZ57/R Vector. It fits to general cloning. Cindicating that mothed modification is practical and convenient for PCR cloning .3. Test has successfully cloned a sequence of Citrus Huanglongbing pathogen, cloned DNA was 99.8% homogous to the GenBank (AY342001.1) of Asian citrus candidates Liberibacter asiaticus, a member of L.asiaticum pathogen.4. This research adopts IR method for fast detecting citrus Huanglongbing for the first time in china. It shows higher accuracy in certain degree and possibility, as a fast, simple and convenient detection method with lower cost. It may combine field symptom to carry out preliminary detection in citrus orchard.5. Through PCR detection, we have collected informatics of citrus...