Occurrence of Curtobacterium flaccumfaciens pv. flaccumfaciens in the state of Paraná and its pathogenicity in beans

Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff) is a bacterial vascular pathogen that infects economically important crops, such as soybean and beans. Currently, this pathogen is widespread in the main bean-producing regions, causing great economic losses. Considering the environmental adaptability of this pathogen and its evolution over time, it is necessary to obtain new information and analyse its status. The objective of this study was to identify whether Cff occurs in the field by collecting plants from different regions in the state of Paraná and determine its pathogenicity in bean plants. For Cff diagnosis, plants with wilt symptoms were obtained from commercial and experimental crops in the Campo do Tenente, Corbélia, Ivaí, Santa Tereza do Oeste, and Sengés municipalities. The samples were subjected to a bacteriological examination and isolation of the bacteria in specific culture medium. To confirm the species of the isolates obtained, specific primers for Cff were used in PCR. The isolates were inoculated into susceptible bean plants (BRS Supremo) to evaluate their pathogenicity. The experimental design adopted was a randomized block design with four replicates. The bacterium was found in all collection locations. Sixteen isolates were characterized as Cff by PCR. The isolates inoculated into the susceptible bean cultivar showed high levels of severity. The results show that Cff isolates in bean crops in bean-producing regions in Paraná show a certain level of field adaptability.