一株新的魔芋软腐病致病菌的生物学特性及基因组分析OA

[Objective]The soft rot pathogen strain(Raoultella ornithinolytica Q-8,accession number:CP173279)was first isolated from the konjac(Amorphophallus spp.)corm.Sequence analysis and gene functional annotation were conducted at the whole-genome level,which will provide a theoretical basis for in-depth research on the pathogenic mechanisms of this strain and its effective control.[Method]Using third-generation whole-genome sequencing technology,genomic data were assembled and genes were predicted through software tools such as Canu,Prodigal,and RepeatMasker.Functional annotation and comparative analysis were performed using 12 databases,including KEGG and PHI-base.A phylogenetic tree was constructed based on the genomic ORF sequences using FastTree2.[Result]The genome size of Raoultella ornithinolytica Q-8 was 5.16 Mb with a GC content of 55.9%,including 4 962 coding DNA sequences(CDSs),6 pseudogenes,11 genomic islands,25 rRNA genes,129 other ncRNAs,and 16 different types of CRISPR systems.Among these,4 833 genes were annotated into 22 gene clusters,and 3 126 genes were enriched in 114 metabolic pathways.Additionally,there were 1 714 transporter-related genes,18 antibiotic resistance-related genes,1 854 pathogen-host interaction-related genes,and 1 067 virulence factor-related genes.Phylogenetic tree analysis revealed that R.ornithinolytica Q-8 and other 8 strains of R.ornithinolytica wore clustered in the same large branch while distantly related to two previously reported pathogens of konjac soft rot,P.carotovorum and D.chrysanthemi.[Conclusion]R.ornithinolytica Q-8 is a novel pathogenic agent causing konjac soft rot.Its genome harbors multiple antibiotic resistance genes and pathogen-host interaction genes,which are likely to play crucial roles in its virulence mechanisms.