A bacterial effector uncovers a metabolic pathway involved in resistance to bacterial wilt disease

Bacterial wilt caused by the soil-borne pathogen Ralstonia solanacearum is a devastating disease worldwide. Upon plant colonization, R. solanacearum replicates massively, causing plant wilting and death; collapsed infected tissues then serve as a source of inoculum. In this work, we show that the plant metabolic pathway mediated by pyruvate decarboxylases (PDCs), activated in response to low oxygen and involved in drought stress tolerance, contributes to resistance against bacterial wilt disease. Arabidopsis and tomato respond to R. solanacearum infection by increasing PDC activity, and plants with deficient PDC activity are more susceptible to bacterial wilt. Treatment with either pyruvic acid or acetic acid (substrate and product of the PDC pathway, respectively) enhances resistance to bacterial wilt, and, as it was reported for drought stress tolerance, acetic acid-induced resistance to bacterial wilt seems to be associated with the phytohormone jasmonic acid. This work reveals a metabolic pathway involved in resistance to biotic and abiotic stresses, and a bacterial virulence strategy to promote disease and the completion of the pathogenic life cycle.