Isolation,Identification And Control Of Pantoea In Wilt Of Mulberry

Mulberry bacterial wilt,also known as mulberry wilt,is a devastating,soil-borne disease caused by multiple pathogens.At present,the pathogen species has not been completely determined.Therefore,it is particularly important to isolate and identify the main pathogens and establish rapid molecular detection methods.In addition,it is also necessary to find antagonistic biocontrol bacteria to achieve safe and long-term biological control purposes.In this study,we collected the mulberry wilt disease from mulberry gardens in several silkworm areas in South China,and purified and identified the pathogens by dilution coating method,plate scribe method,morphological identification,physiological and biochemical identification,and molecular biological identification.High-throughput sequencing and bioinformatics analysis of whole-genome sequencing,assembly and annotation of pathogens and comparison of primers to obtain specific segments,establishing rapid molecular detection methods for pathogens;through indoor plate inhibition,pot control,silkworm safety test To investigate the efficacy and safety of two chemical agents,Chlorobromoisocyanurate and salicylic acid(SA);use the indoor plate bacteriostatic test to screen for biocontrol bacteria that have better antagonistic effects on pathogenic bacteria.It was identified by morphological feature identification,physiological and biochemical identification,molecular biology identification,sequencing,assembly and annotation of its genome by high-throughput sequencing and bioinformatics analysis.The main findings are as follows:(1)Ralstonia solanacearum,Enterobacter cloacae,new in the sensation of mulberry wilt in Liuzhou,Xiangzhou,Yucheng,Liucheng,Yingde,Shunde,Guangxi,Guangxi The pathogen Pantoea ananatis;P.ananatis LC001 genome: 4,499,350 bpg,81 t RNAs,22 t RNAs,3418 CDS(coding genes),GC content 55.15 %.The strain was deposited in theGuangdong Provincial Collection of Microorganisms and Cultures,GDMCC No: 1.1601.(2)The whole genome of Pantoea sinensis was obtained by the specific genome of1061295-1062175 bp,and the primer FJ-F1/FJ-R1 was designed.The molecular detection method of P.ananatis LC001 was established.(3)The control results of chlorobromoisocyanuric acid and salicylic acid against three pathogens of Fusarium oxysporum,R.solanacearum and Enterobacter cloacae showed that different concentrations of chlorobromoisocyanuric acid against three pathogens Plate antibacterial concentration range is 500 mg / L-5 g / L,500 mg / L-5 g / L and 250 mg / L-5 g / L,1000 mg / L chlorobromoisocyanuric acid for different pathogenic The disease index of mulberry wilt caused by bacteria decreased,and the disease index of Fusarium oxysporum decreased by 50%,and the control effect was 71.4%,which reduced the disease index of Fusarium oxysporum by 60%.For 75.0%,less than 1000mg/L chlorobromoisocyanuric acid had no significant effect on the growth and development of silkworm and the quality of enamel(P > 0.05).The inhibitory concentrations of salicylic acid on three pathogens ranged from 500 mg/L to 2000 mg/L,500 mg/L to 2000 mg/L,and250 mg/L to 2000 mg/L,respectively,and 1000 mg/L salicylic acid.The disease index of mulberry wilt caused by different pathogenic bacteria decreased,and the disease index of Fusarium oxysporum decreased by 55%,and the control effect was 73.3%;the disease index of Fusarium oxysporum caused by Pantoea acuminatum decreased by 55.%,the control effect was 78.5%,and salicylic acid less than 1000mg/L had no significant effect on the growth and development of silkworm and the quality of tannin(P > 0.05).(4)P.aeruginosa YD-001 was isolated from the root tissue of mulberry tree and had a good antagonistic effect on mulberry wilt and tobacco disease.The antagonistic bacteria have good antagonistic effects on the pathogens of mulberry wilt,Pantoea acuminata,R.solanacearum and Enterobacter cloacae,and the bacteriostasis rate of Fusarium oxysporum to tobacco root rot pathogen is 83%.The bacteriostatic rate of Phytophthora parasitica is 75%.The whole genome sequencing results showed that the full-length was6,496,756 bp,the GC content was 66.27%,the encoded protein gene was 5560,the t RNA was 8 and the t RNA was 64.In summary,this study isolated the new pathogen P.ananatis from the mulberry wiltdisease sample,and completed the genome-wide sequencing,assembly and annotation and rapid PCR molecular detection methods for the mulberry wilt The research and prevention laid the foundation;in addition,the research on the prevention and treatment methods of chlorobromoisocyanuric acid and salicylic acid,the isolation and identification of antagonistic bacteria,provide a theoretical and practical reference for the control of mulberry wilt.