Mode Of Action Of Amicarthiazol To Xanthomonas Citri

Toxicity mechanism, pl~rmacology, resistance risk, physiological and biochemical characters, and targets of attacking site et al. were studied in citrus bacterial canker disease (CBCD) pathogen Xunthomonas citri inhibited by carboxamides fungicide amicarthiazol. Action of amicarthiazol to plant pathogen bacteria was first charactered systemly in abroad and domestic researches. Intensely selection was indicated in inhibition of amicarthiazol to plant pathogen bacteria Xanthomonade such as X oryzae pv. oryzae, X o. pv. oryzicola, X citri, and X glycines et al. with high activity of efficient inhibitory medium concentration (EC50) 0.5745, 1.3026, 2.6257 and 7.4970kg 秐L1 in vitro, respectively. Little inhibition was showed to Pseudomonas syringae pv. syringae, Ralstonia .solanacearum and Erwinia carotovora pv. carotovora. However. EC50 of hismerthiazol. carboxin. diisothiocyanatomethane and streptotnycin sulfate were 3.6269, 2.8547, 0.1485, 0.040%.tg mU? It showed that inhibitory efficiency of aniicarthiazol was better than that of carboxin and bismerthiazol, yet less than diisothiocyanatomathane and streptomycin sulfate to the growth of bacterium X citri. Thiram and pH tendency had no influence on inhibition to the pathogen, glucose oxidation and utility by cell of X citri was 5.3 times in medium with sodium acetate solely hig~r than with glucose as sole carbonic resource. The functions of toxicity radicals with the similar structures were minor 112 difference through comparison of toxicity mechanism among amicarthiazol, bismerthiazol and carboxin. They all had well inhibitory efficiency to the growth of plant bacterial disease pathogen and Rhizocto,iia cerealis. But bisnierthiazol had little toxicity to Rhizoctonia cerealis. The median inhibitory concentrations (MIC) of X curl to amicarthiazol and carboxin were 10014g. mV and 40014g ml]?respectively, it reflected that some different tolerances were exjsted between amicarthiazol and carboxin. Under the same efficient concentration effect of amiearthiazol was better than total of the effect of bismerthiazol and carboxin to the -growth and the respiration of X carl. However. Bismerthiazol could stimulate the respiration of the bacterium on some distance in low concentration. The results indicated that thiazole and benamidemetide structures in the molecular structure of amicarthiazol all had bioactivity to X cUrl. Extracellular secretions of X cUrl had certain abilities to regulate the interaction course between amicarthiazol and the bacterial cell. The secretions, especially extracellular polysaccharide (BPS), could strongly antagonize the inhibition of amicarthiazol. Output of electrolyte, El扴, extracelkilar protein, and bioactivity of extracehlular hydrolytic enzymes were regularized to vary with the concentration of amicarthiazol. To be noted that 73.74% product of ex~acelluIar protein of the bacterium treated with 2014g. mU?amicarthiazol was inhli,ited. l~ut the activity of extracellular proteinase increased with concentrati(n of aznicarthiazol till up to 1014g. mU1. The results made known that the pathogenic bacteria possess an active echo to the adverse environment by changing the atti~butions of extracellular secretions enriching its cytoplasm when surrounded by fungicides to minor the probable touch to amicarthia~ol. Many researches were further to make clear diet the inhibitory rate was great different during different growth stage of...