Study On Tomato Resist Alternaria Alternate Induced By Chitosan Oligosaccharide And Extraction Of Bacteria Toxin

The nutrition of tomato fruit is rich, loved by people of all countries, but susceptible to the pathogen infection, because the fruit is ripe pulp juice cause decay,especially the Alternaria solani infection caused by toxin residues, fresh and processing tomato can cause significant loss, restricted the development of tomato fruit processing and preservation industry. The biological source ofoligochitosan induced resistance agent, provide a new idea for thepreservation of fruits and vegetables.This paper takes chitosan oligosaccharide as exogenous antistaling agent, to study on the microscope and spectrophotometer detection method of tomatoAlternaria black mildew preventive effect and mechanism, at the same time fortoxigenic and pathogenic mechanism of Alternaria spp. by HPLC and mass spectrometry analysis, combined with the biological detection, determinationthe mechanism of toxin in pathogenic bacteria infection, to provide the theoretical basis for the key Alternaria spp. in biotechnology to control invasivefactor. The effect of tomato black mold prevention and treatment were studied in this paper.I investigated the effects of chitosan oligosaccharide on Alternaria fungus hyphae and spores, and the results showed that different concentrations of chitosan oligosaccharide on Alternaria mycelium had no inhibition, and on the contrary the result of0.05g/100mL was promotion; different concentrations of chitosan oligosaccharide on bacteria spore germination had clearly inhibited, and the concentration of0.10g/100mL made spore germinated hardly. Alternaria fungus was cultivated by liquid medium with the addtion of different concentrations of chitosan oligosaccharide (0.01g/100mL,0.05g/100mL,0.1g/100mL),and then the catalase (CAT) activity of Alternaria was detected. The result showed that the catalase(CAT) activity was inhibited from1to3days, followed by hydrogen peroxide activity rised, and with the higher of the concentration of chitosan oligosaccharide, the catalase activity was lower.The developing solvent (ethyl acetate:methanol:water=7:2:1, v/v/v) was used to expand the crude toxin, and found that there were four main ingredients with color reaction.The crude toxin was chromatographed through silica gel column chromatography.36bottles of elution were collected, and the solution of1～19bottles was the main active ingredient. The collection of10～19bottles was called fine toxins.The HPLC analysis of the crude toxin showed that there was mainly one single component whose retention time was3.492min.The infrared spectroscopy showed that the major peak of the absorption band was in the fingerprint, which indicated that Alternaria may contain the groups of NH,-CH2, C=C, etc, and there may be contain C-O, C-N, C-C groups in stretching zone. Gas chromatography-mass spectrometry analysis was used to analyzed the crude toxin samples, and7seven major organic compounds were detected. The main component was hexazinone, whose hemical formula wasC12H20N4O2, and molecular weight was252.31. Net grass was its another name, which was the main component of a herbicide.Tomato liquid toxin had a significant inhibition of four defensive enzymes of POD, PPO, PAL, SOD, and the decreases of enzyme activity is the main reason for the decline of tomato disease resistance;When the toxin stock solution was diluted, the inhibition was weakened, and the defensive activity increased when the dilution was20times. When tomato was dealed with0.05g/100mL concentration of oligochitosan in advance, and then toxin was injected, the defense enzymes had been strengthened, which played on the effect of disease-resistant tomato fruit. Therefore, the toxin had a dual role.The high concentration of the pathogenic played a significant pathogenic role, and the low concentrations could enhance the plant defense activity. Throughing soluble protein content and conductivity analysis, the result showed that with the higher concentration of the toxin, the tomato soluble protein content was lower and permeability of the greater of tomato cells When using0.05g/100mL concentration oligochitosan solution, the protein content of tomato cells was significantly increased and membrane permeability was also smaller.