Observation of Wilting Symptoms Caused by Cell Free Filtration of the Culture in Pseudomonas fluroescens

External symptoms were observed and compared in Pinus thunbergii inoculated with different inoculants including cell free filtration of the liquid culture of the pathogenic bacterium,Pseudomonas fluorescens GcM5-1A strain,carried by Pine Wood Nematode(PWN),Bursaphelenchus xylophilus,the mixture of aseptic B.xylophilus and the pathogenic bacterium strain,aseptic B.xylophilus and the mixture of aseptic B.xylophilus and the non-pathogenic bacterium,Staphylococcus lentus AM2C strain.The main results are as follows:(1)External symptoms of P.thunbergii inoculated with cell free filtration of the pathogenic bacterium GcM5-1A were consistent with those of the trees inoculated with wild PWN in external symptoms.However,the external appearances of the trees inoculated with aseptic PWN and those of the trees treated with the mixture of aseptic PWN and the non-pathogenic bacterium,Staphylococcus lentus,AM2C were the same as those of the healthy P.thunbergii;(2)The symptoms and time(d) to show them between trees inoculated with cell free filtration of the pathogenic bacterium GcM5-1A and those inoculated with wild PWN were not significant;(3)The whole disease process in trees of P.thunbergii inoculated with the mixture of aseptic PWN and the patho genic bacterium GcM5-1A lasted significantly longer than that of those inoculated with wild PWN.The results above can be explained by the hypothesis,pine wilt disease is a complex one induced by both PWN and the pathogenic bacteria carried by it and the mutualistic symbiotic relationship between PWN and the pathogenic bacteria carried by it.And it is also demonstrated that the toxic materials produced by the pathogenic bacteria carried by PWN are the very causes of the wilt.