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The first report of bacterial soft rot Dennis bromeliad (Guzmania denise) occurred in Hainan, detailed description of the symptoms and hazards of the disease, and isolated from Dennis diseased four strains D1-D4. The separation of four strains morphology, Gram stain, pathogenicity, cultural, physiological and biochemical properties, host range determination, according to Berger bacterial identification manual eighth edition, initially identified the taxonomic status of pathogenic bacteria . Dennis pineapple bacterial soft rot on four separate strains 16S rDNA sequence analysis, phylogenetic tree, further determine the classification of vesting. The separation of four strains Fungicide screening. Dennis pineapple bacterial soft rot in plants show leaf rot, heart rot two symptoms. Heart rot type: onset period leaf qualitative change in translucent lesion pale green was water-soaked, the edge gradually becomes tawny, gradually rotting accompanied by a foul odor, serious gently from the rot at the can pull off, and stems Ministry of detachment. Spread down to the roots, soft rot diseased tissues, leading to plant death. Leaf rot type: early onset leaves dark green water-soaked lesion gradually extended veins extended diseased tissues turn brown soft rot, clearly with healthy organizational boundaries. Late onset disease tissue dry rot, to the whole plant death. Under the appropriate temperature and humidity conditions, disease rapidly expanding, is the planting zone Dennis pineapple on fatal diseases. The disease has not been reported, Dennis pineapple is the new host of the corresponding bacteria. According to the the morphological identification results and bacteriology trait measurement results, the four strains are gram-negative bacilli (G), whip Maozhou Sheng, no capsule, does not produce spores, facultative anaerobic sports does not generate a fluorescent dye, and in line with the characteristics of the bacteria Erwinia (Erwinia sp.) The physiological and biochemical test results showed that the four strains in the 37-C and 5% NaCl growth enables potato soft rot, liquefied gelatin, and does not produce indole, lecithinase reaction negative, reducing substance produced from sucrose, can use mannitol maltose, trehalose, rhamnose, dulcitol, α-methyl glucoside, cellobiose, inulin, D (-) arabinose, D () raffinose, melibiose acid production, but could not use , lactose, sorbitol and acid production, sodium tartrate, sodium malonate, sodium citrate, sodium succinate, but not the use of sodium benzoate; sensitive to erythromycin; 16S rDNA sequence analysis results showed that four of the measured strains (D1-D4) similar values ??and Echrysanthemi standard strain sequence homology Dickeya zeae (AF520711.2) in more than 97%. The four strains of 16S rDNA sequences in GenBank accession number: JF779680-JF779683. Design daisy pectin genus the six biotypes identify experimental, the four strains bacteriological characteristics in addition to the lecithinase a different, other traits with corn pathogenic variants E.chrysanthemi pv.zeae consistent. Control \f.sp. zeae Sabet 1954 named Dennis pineapple bacterial soft rot disease. The inhibition zone method for the determination of the six kinds of bactericidal agent Dennis pineapple bacterial soft rot bacteria inhibitory effect. The results showed that: 72% streptomycin WP antibacterial effect, inhibition zone of the largest and most obvious, the linear regression equation y = 5.3444 7.5179x the ECso as 0.9552; 800,000 medical units penicillin and 50% enemy sodium sulfonate WP inhibitory effect, followed by the linear regression equations were y = 1.6128 5.6902x y = -12.35 4.8104x EC50 1.8135 and 36.8468. These three agents as Dennis pineapple bacterial soft rot field efficacy trials preferred pharmacy.
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