| Blackleg is one of the main bacterial diseases of potato that has a serious impact on potato production.In recent years,potato blackleg occurred frequently in China,accompanied with the discoveries of new pathogens.Pectobacterium parmentieri is one of them.Study of this newly discovered pathogen is important for establishing the disease control management.In this study,we characterized the morphology,physio-biochemistry,and pathogenicity of 4 P.parmentieri strains discovered in Inner Mongolia in 2019,and the results were compared with other 3 potato blackleg pathogen strains,including Pectobacterium atrosepticum,Pectobacterium brasiliense,and Pectobacterium carotovorum.We did the genome-wide sequencing analysis,and designed specific PCR primer for detection of P.parmentieri.The main results are followings:1.Strains named WC19161,JN19121,AR19131,and AR19132,isolated from potato blackleg samples in Hohhot,Ulanqab,and Hulunbuir,were identified as P.parmentieri,based on sequencing blast analysis.2.No significant difference in colony morphology,physio-biochemistry characteristics and drug resistance were found between these 4 strains and P.atrosepticum,P.brasiliense,and P.carotovorum.The pathogenicity of P.parmentieri is only weaker than P.brasiliense(P=0.038).P.parmentieri could specifically utilize potassuim 2-ketogluconate,and there was no specific difference in enzyme activity.P.parmentieri showed no special resistance,and was not resistant to benziothiazolinone,chloroisobromine cyanuric acid,kasugamycin and copper hydroxide.3.Strain WC19161 was used for the genome-wide sequencing analysis.The full length of its genome is 4990747 bp,including 4609 coding genes,6 interspersed repeats types and 2 tandem repeats types.Fifteen gene islands obtained by horizontal gene transfer,15 pre-phage sequences,and 4 CRISPR related to bacteriophage infection were obtained.Strain WC19161 was still identified as P.parmentieri at the genomic level by ANI and d DDH.Compared with the type strain P.parmentieri RNS08-42-1,about 18% of its genome has structural variation(including translocation,inversion,and insertion).It has T6 SS,but lacks of T3 SS.There is no gene that showed 100% identity to the known drug resistance gene sequence.4.The primers for specific P.parmentieri PCR/q PCR detection were designed.Ppar1-F/R shows the best specification and application efficiency. |
