The Inhibition Of BIT Against Botrytis Cinerea And The Studies On The Mechanism

1,2-benzo-isothiazolin-3-one(BIT) is a kind of low toxicity, high efficiency, good water-soluble fungicidcs.It has prominent inhibitory effect on bacteria, fungi and other microorganisms, which is widely used in industry. Then how is its inhibitory effect on agricultural microbiology, especially grey mold by developing BIT as a new type of agricultural pesticide?And what is the mechanism? This paper selects Botrytis cinerea as an original target.By using mycelial growth rate to determine inhibition of BIT against grey mold and through the hyphae microstructure observation, three levels of Physiological and Biochemical Indexes (Bacterial cell wall, cell membrane, nucleus).the mechanism of BIT against B.cinerea was studied.The results are as follows:1.BIT had a strong inhibitory effect on Botrytis cinerea and its inhibitory medium concentration (EC50) was 69.95μg·mL-1 by experiment determination.2.The TEM observation after BIT acting on the grey mold showed that Cell wall structure was damaged, while the decline of chitin content was measured.The results showed that BIT led to chitin structural damage in bacterial cell wall.3. After adding BIT. conductivity of Botrytis cinerea hyphae gradually increased, the leakage of soluble proteins and soluble sugars increased in solution,which showed that cell membrane permeability was changed by BIT. resulting in leakage of the inclusions.4.β-1,3 glucan synthase activity decreased while chitinase activity increased were found after adding BIT by experiments onβ-1,3 glucan synthase, chitinase activity assay.That led to the biosynthesis block of Portuguese and Rapid decomposition of chitin, which revealed the reasons of destruction of bacterial cell wall structure.5.Through experiments about the catalase activity assay,the reduction of catalase activity was found, which resulted in reduction of detoxification, affecting the cellular energy metabolism activity.The result is consistent with the mechanism of industrial sterilization. 6.Agarose-gel-electrophores experiments after different concentrations of BIT applied to grey mold showed that genomic DNA content changed little between different treatment groups. Combining with the pictures of transmission electron microscope, it indicated that BIT did not damage DNA of Botrytis cinerea.