The Ferredoxin-Like Protein FerR Regulates PrbP Activity in Liberibacter asiaticus

Abstract

The rapid spread and aggressive progression of huanglongbing (HLB) in the major citrus-producing areas have raised global recognition of and vigilance to this disease. As a result, the causative agent, Liberibacter asiaticus , has been investigated from various perspectives. However, gene expression regulatory mechanisms that are important for the survival and persistence of this intracellular pathogen remain largely unexplored. PrbP is a transcriptional accessory protein important for L. asiaticus survival in the plant host. In this study, we investigated the interactions between PrbP in L. asiaticus (PrbP Las ) and a ferredoxin-like protein (FerR) in L. asiaticus , FerR Las . We show that the presence of FerR stabilizes and augments the activity of PrbP Las . In addition, we demonstrate that the expression of ferR is induced by increases in osmolarity in Liberibacter crescens . Altogether, these results suggest that FerR Las and PrbP Las may play important roles in the regulation of gene expression in response to changing environmental signals during L. asiaticus infection in the citrus host.