Synthesis Of Chitosan Schiff-base And Its Antifungal Mechanism On Botrytis Cinerea

Objective: Studied the antifungal activity of four Chitosan Schiff-bases(CTS-Sal, CTS-2Hy, CTS-Val, CTS-O-val) on Botrytis cinerea, and the antifungal mechanism of Schiff-base that had best antifungal activity among the four Chitosan Schiff-base. Methods: The structures of chitosan Schiff-bases were characterized by FI-IR and UV spectroscopy. The MIC and EC50 of CTS and four Schiff-bases on Botrytis cinerea was determined by using methods of micro liquid dilution and fungal mycelial growth rate method. Botrytis cinerea was observed in transmission electron microscope after being treated by Schiff-base that had best antifungal activity, from three levels of Physiological and Biochemical Indexes(Bacterial cell wall, cell membrane, nuclear), the antifungal mechanism of Schiff-base that had best antifungal activity was studied. Data were collated, inputed and analysed by SPSS17.0 statistical software. Measurement data were expressed by SX ±, and data among multiple group were compared by MANOVA of repeated measuring and simple effect analysis.Results: 1. IR and UV spectrum analysis showed that four kinds of aldehydes had been combined in CTS carrier. 2. Compared with CTS, four chitosan Schiff-bases had significant resistant activity against Botrytis cinerea, among them, the MIC and EC50 of CTS-2Hy were both the lowest, which reached 1184.49 and 724.44μg/m L; 3.Botrytis cinerea were observed in Transmission electron microscope after being treated by CTS and CTS-2Hy, founded that the cell wall of the bacteria cell was blurred,even serious loss, the cell wall integrity was destroyed, the cell membrane was broken, while the nuclears had no obvious changes, while the cell structure of CTS group was integrity. At the same treatment time, the chitin content of group CTS-2Hy was lower than those of group CTS(P<0.01). 4. The conductivity of group CTS-2Hy were higher than those of group CTS at 12 h, 16 h, 20h(P < 0.01); The leakage of soluble protein of group CTS-2Hy was higher than that of group CTS at20h(P<0.01), and the leakage of soluble sugar of group CTS-2Hy were higher than those of CTS group at 8h, 12 h, 16 h, 20h(P < 0.01); 5. The β-1,3-glucan synthase activity of group CTS-2Hy were lower than those of group CTS at 4h, 8h, 16 h, 64h(P<0.01); The chitinase activity of group CTS-2Hy was higher than that of CTS group at 16 h and 32h(P<0.01); 6. The catalase activity of group CTS-2Hy were lower than those of CTS group at the same treatment time(P < 0.01); 7. The different concentration of CTS and CTS-2Hy had acted on DNA, respectively, the difference between the concentration of genomic DNA had no statistical significance(P>0.05).Conclusion: 1. Schiff base reaction have been occurred between four kinds of aldehyde and chitosan, respectivly; the antifungal activity of CTS-2Hy is the best among the four chitosan Schiff-bases. 2. CTS-2Hy has affected the cell membrane,and the cell membrane permeability has been changed, and CTS-2Hy has influenced the membrane and intracellular enzymes activity by disrupting the cell membrane, β-1,3 glucan synthase activity decreased while chitinase activity increased are found after being treated by CTS-2Hy, that lead to the biosynthesis block of Portuguese and Rapid decomposition of chitin and cell wall structure is damaged, with catalase activity decreased, detoxification is reducing and metabolic activity of cells is affected,that lead to Botrytis cinerea is inhibited or killed. 3. The impact of CTS-2Hy on the nuclear has a further study.