Plasmid composition and the chpG gene determine the virulence level of Clavibacter capsici natural isolates in pepper

Abstract

Clavibacter species are gram-positive plant pathogens that belong to phylum Actinobacteria (Eichenlaub and Gartemann, 2011). The genus Clavibacter includes six species: C. capsici causes necrosis, wilting, and bacterial canker in pepper; C. michiganensis causes wilting and bacterial canker in tomato; C. sepedonicus causes ring rot in potato; C. nebraskensis causes wilting and blight in maize; C. insidiosus causes wilting and stunting in alfalfa; and C. tessellarius causes bacterial mo

Transcriptional Changes of Plant Defense-Related Genes in Response to Clavibacter Infection in Pepper and Tomato

“…As we mentioned above, the high-virulent strains of C. capsici caused severe necrotic symptoms on pepper leaves within 7 dai. The expression of the virulence genes in high-virulent and/or low-virulent C. capsici strains was analyzed in the previous report ( Hwang et al, 2020 ), showing that the transcript level of plasmid-borne virulence genes was differentially induced by the presence or the absence of the small plasmid, pCM1 Cc . In particular, we found that the expression of most plasmid-borne virulence genes tended to decrease in low-virulent strains after inoculation in plants.…”

“…In the previous study, we reported C . capsici natural isolates with differential virulence level in pepper plants ( Hwang et al, 2020 ). To explore the role of defense mechanism in pepper plants, especially the expression of defense-related genes depending on virulence difference of C. capsici strains, we selected C .…”

“…For pepper plant inoculation, the highvirulent strains C . capsici PF008 and 822 and the low-virulent strains PF008ΔpCM1 Cc and 1101 (lacking pCM1 Cc ) ( Hwang et al, 2020 ) and for tomato plant inoculation, the high-virulent strains C . michiganensis LMG7333 ( Hwang et al, 2019 ) and KACC16995 and the low-virulent strain LMG3685 ( Yim et al, 2012 ; Oh et al, 2016 ) were used in this study.…”

“…Importantly, in both C . capsici and C. michiganensis , there was no positive correlation between bacterial growth and virulence level ( Hwang et al, 2020 ; Thapa et al, 2017 ), meaning that both the high-virulent and low-virulent strains of both bacteria could grow well similarly inside host plants.…”

“…A recent study reported that C . capsici strains with different levels of virulence exist in Korea and that this virulence depends on the plasmid carrying the virulence genes ( Hwang et al, 2020 ). The small plasmid, pCM1 Cc of C .…”