Molecular Detection Of Xanthomonas Axonopodis Pv. Dieffenbachiae In Authurium Andreanum And Laboratory Screening Of Bactericides

Bacterical blight in Anthurium andraenum is an epidemic disease, which seriously hinder thedevelopment of the Ahthurium industry. Three ways were exploited to study the pathogen, theidentification of pathogens, molecular detection in initial stage and screening of bactericides. Thepurpose is that a rapid and sensitive method was established for detecting pathogen and the efficientbactericides were screened for inhibiting the development of disease. The results as follows:1. Identifying the pathogen which of Bacterical blight infecing Authurium andreanum isXanthomonas axonopodis pv. dieffenbachiae by Koch’s postulate and others physiological verificationto combine seauence alignment analysis of16S-23S ITS. The results of pathogenic detection showedthat X. axonopodis pv. dieffenbachiae can infect the majority of24different cultivated varieties ofAnthurium andraenum.2. According to the RAPD of X. axonopodis pv. dieffenbachiae，specific primers were designed,andbinding ability of magnetic beads were tested. The system of optimization of immunomagneticseparation-PCR protocol for detecting the Bacterial blight of symptomless infected Anthuriumandraenum were establisted. The results showed that the saturate absorption of1mg carboxyl magneticbeads to the polyclonal antibodys is0.268mg. The optimal concentration of immunomagneticbeads（IMB） is0.566～0.741mg.mL^-1when X.axonopodis pv. dieffenbachiae is captured. The detectionsensitivity for X. axonopodis pv. Dieffenbachiae by IMS-PCR is10～100cfu.mL^-1,100times moresensitive than ordinary PCR. Using this method to detect symptomless Anthurium andraenum achievedgood results.3. X. axonopodis pv. dieffenbachiae was detected by Taqman fluorescence probe RQ-PCR. Theresult showed that specific primers and Taqman fluorescence probe designed, according to the X.axonopodis pv. dieffenbachiae insertion sequence ISXCD1transposase gene can specifically andSensitively detect X. axonopodis pv. dieffenbachiae total DNA, The detection sensitivity is100fg.μL^-1.Using this technique to quantify the copy number of amplification sequence of total DNA of Anthuriumandraenum leaves in different stages of infection. According to the analysis, differences of copynumber has positive correlation with the degree of disease development. So, the RQ-PCR can furtherdevelop to track the dynamic changes of pathogen in Anthurium andraenum and evaluate the resistancelevel of different cultivars.4.11efficient bactericides for inhibiting pathogen which contain3antibiotics（rifampin，penicillinsodium，Oxytetracycline）and8agricultural chemicals（80%ethylicin,3%zhong-shengmycin,86.5%Copper（I） oxide,25%Bromothalonil,20%Bronopol,70%Sulfur.Mancozeb and so on）werescreened from16agricultural chemicals and6antibiotics which are used in medical domain by Minimalinhibitory concentration and inhibition zone. taken all factors into consideration, the results showed that80%ethylicin and3%zhongshengmycin has a high popularization value.