Cross-inoculation and host responses to Curtobacterium flaccumfaciens pv. flaccumfaciens in common bean, soybean, and cowpea: pathogenicity, symptom expression, and xylem colonization

Genetic variability within a pathogen species underlies its ability to infect multiple plant species. Curtobacterium flaccumfaciens is a notable example of a pathogen capable of colonizing plant tissues across different species, including those within the same family or across distinct families. The pathovar flaccumfaciens comprises isolates that induce both systemic and foliar symptoms in common beans and soybeans, leading to Curtobacterium wilt and bacterial brown spot diseases. Understanding the pathogen’s behavior across various hosts is essential for developing effective strategies to mitigate its detrimental impact on crop productivity. This study evaluated the systemic and localized infection capacity of Curtobacterium flaccumfaciens pv flaccumfaciens ( Cff ) isolates originating from different host species in soybean, common bean, and cowpea cultivars using distinct inoculation methods. The results demonstrated that Cff isolates obtained from soybean plants elicited varying symptomatology across the three legume species. Furthermore, differential host reactions were observed among the tested cultivars when inoculated with the same Cff isolates.