Study On The Pathogen Of Cortex Phellodendron And Its Biological Control

The basic research methods of forest pathology and molecular biology are used in this paper.Isolation,purification,pathogenicity determination and morphology and molecular identificaition of the pathogen of canker rot in Phellodendron amurense.Screening of endophytic bacteria with good biological and protective effects on canker rot in Phellodendron amurense.The isolation and identification of the strain,the study of the antagonistic mechanism and the field control experiment of the strain were carried out in turn.Biocontrol potential of antagonistic bacteria to canker rot in Phellodendron amurense.In order to effectively control the disease development and reduce the loss caused by the disease.Study on endophytic bacteria,to create green,safe and efficient anti made foundation of excellent students to provide scientific basis.The following results are mainly obtained:1.Pathogen of canker rot in Phellodendron amurense in SichuanField survey on the occurrence and damage extent of canker rot in Phellodendron amurense at Dayi Country in Chengdu of Sichuan Province.It was found that the disease began to occur in March,from June to July,cessation of development in October.Through the airflow,the rain spread.Indoor separation by collecting plants,pathogenicity determination and morphological identification,binding of ribosome gene transcriptional septum and sequence analysis of translation lengthening factor gene,the pathogen of canker rot in Phellodendron amurense is Nectria haematococca.The growth effect of the bacteria on PDA medium is the best,the optimum growth temperature is 25℃,the best growth is under the conditions of light alternation and pH is 7,in the carbon source and nitrogen source of the test,the growth of sucrose as the only carbon source is the best,the growth of potassium nitrate is better as the only nitrogen source.2.Isolation of endophytic biocontrol bacteria,screening and identification34 strains of endophytic bacteria were isolated from the healthy canker rot in Phellodendron amurense from sample plots,antagonistic test of pathogenic bacteria by plate confrontation andgrowth rate method,1 strains of cypress endophyte with strong antagonism and less study were screened,which was numbered B18.Morphological identification,physiological and biochemical experiments and 16 S r DNA homology analysis,the bacteria were identified as Bacillus methylotrophicus.3.Study on endophytic biocontrol antagonistic mechanismDetermination of bacteriostatic activity by inhibition of mycelium growth rate and perforation,results show,a stable bacteriostasis effect of aseptic fermentation broth of B18 strain on the pathogen of canker rot in Phellodendron amurense,the rate of bacteriostasis was 85.37%.Further discovery through experiments,the aseptic fermentation broth of B18 strain can significantly inhibit the normal growth of mycelium and destroy the mycelial structure,the phenomenon of aberrant swelling,distortion,fracture,and protoplast exudation.The germination rate of spores gradually decreased with the increase of the concentration of aseptic fermentation broth of B18 strains,deformity of spores.The study of its antibacterial active substance showed that the tested strain B18 could secrete the chitinase,but β-1,3 glucan enzyme was not produced.4.Field prevention and control of canker rot in Phellodendron amurenseThe field experiment was carried out by spraying,the results showed that the cure was the most significant and the cure rate was up to 96%.With the increase of the degree of dilution,the incidence of the disease is also increasing,and the effect of disease prevention is decreasing.In the application of forestry production practice,it is suggested that 400 times liquid preparation is used.The 400-800 times(volume ratio)dilution of liquid preparation in the unyellow berlin area was sprayed along the stem,once every spring,it can prevent the occurrence of canker rot in Phellodendron amurense.