Study on biocontrol potential of antagonistic bacterium QZ-1 against tomato Botrytis cinerea
In order to clarify the biocontrol potential of strain QZ-1 against tomato gray mold,the antagonistic bacteri-um QZ-1,isolated from the rhizosphere soil of peach trees in Qingzhou,Shandong Province,the antifungal activity was determined.The antagonistic effects of strain QZ-1 on various phytopathogenic fungi and the control effect against tomato gray mold were assayed using plate confrontation assays and fruit inoculation tests.The results showed that strain QZ-1 dis-played different degrees of inhibitary ability against tested plant pathogenic fungi.Moreover,the sterile filtrate of QZ-1 could sig-nificantly inhibit mycelial growth of B.cinerea,Phomopsis amygdali and Sclerotinia sclerotiorum,and the inhibition rates were 80.00％,77.33％and 76.67％respectively.QZ-1 also exhibited a good biological control effect to B.cinerea in tomato fruit.Strain QZ-1 displayed 99％similarities with that of Bacillus velezensis and B.amylolique faciens based on the 16S rDNA and rpoB sequence analysis.Combined with the physiological and biochemical traits,the strain QZ-1 was identified as B.velezensis.PCR amplification results showed that the presence of 1 203 bp ituD and 1 400 bp fenB genes,coding for iturin A and fengycin,in the genomic DNA of QZ-1.Mass spectrometry analysis suggested that the iturin A and its homologues were the main antimicrobial compounds produced by QZ-1.In summary,B.velezensis QZ-1 effectively inhibits the mycelia development of B.cinerea through the iturin A production,and provides an excellent new biocontrol resource for controlling of tomato gray mold.
Botrytis cinereaBacillus velezensisiturinbiological control
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