Isolation And Identification Of Endophytic Bacteria Strain W5 From Ginkgo Biloba

The quantities of endophytic bacteria isolated from Ginkgo biloba cellected from Shunchang county and the campus of Fujian Agriculture and Forestry University were 1.0-25.2×10~3cfu/(g.fw). Analysising different parts of plants,the number of endophytic bacteria isolated from branches of G. biloba was significantly more than leaves.Analysising different areas,the number of endophytic bacteria isolated from G. biloba of Shunchang county was significantly higher than that of the campus.There were 9 strains screened from the isolates.Which had antagonism to pathogens of Phytophthora capsici,Pyricularia grisea,Rhizotonia solani,Fusarium oxysporum,Peronophythora litchii and Geotrichum candidum.The Antagonistic capacity of strain W5 was the best among the strains,especially to P. capsici,the bacteriostasis bandwidth of strain W5 reached to 9.0 mm,and the bacteriostasis rate reached up to 88.9%.Strain W5 was identified as to be Bacillus amyloliquefaciens by morphological, physiological and biochemical characteristics, and analysis of 16S rDNA.The results of disease control to the pepper phytophthora blight of capsicum fruit showed that when the pepper fruit was sprayed with strain W5 first then innoculaed the pathogen, it could reach 100.00% control efficacies after two days,but only 11.96% when sprayed whith strain W5 after inoculation of the pathogen.The control efficacy of strain W5 would get the best,when the pepper fruit was treated with strain W5 for 2d to 3d,then inoculated the pathogen.Tests also showed that when capsicum fruit treated with strain W5,there were sparse white fimbria on the pecidel of most capsicum fruit and the pepper fruit retained green and hard.Otherwise,there were bushy white fimbria covering whole pepper fruit which was appearing waterish and the part of tissues turned into yellow and collapsed.The colonization proficiency of strain W5 showed that the double tagged bacteria could live stably inside of the tissues of G. biloba.The quantity of the bacteria were about 1.66×104 cfu/(g.fw).In the early stage,the tagged bacteria gathered in the epidermal cells and spreaded into the mesophyll cells through the epidermis and the stomata,then gathered around the vascular bundles.In the late stage,the tagged bacteria were sporadicly around the vascular bundles and cell gap,not diffusing into cells.