Rhizobiales-Specific RirA Represses a Naturally "Synthetic" Foreign Siderophore Gene Cluster To Maintain Sinorhizobium-Legume Mutualism.

ABSTRACT: Iron homeostasis is strictly regulated in cellular organisms. The Rhizobiales order enriched with symbiotic and pathogenic bacteria has evolved a lineage-specific regulator, RirA, responding to iron fluctuations. However, the regulatory role of RirA in bacterium-host interactions remains largely unknown. Here, we report that RirA is essential for mutualistic interactions of Sinorhizobium fredii with its legume hosts by repressing a gene cluster directing biosynthesis and transport of petrobactin siderophore. Genes encoding an inner membrane ABC transporter (fat) and the biosynthetic machinery (asb) of petrobactin siderophore are sporadically distributed in Gram-positive and Gram-negative bacteria. An outer membrane siderophore receptor gene (fprA) was naturally

SUBMITTER: Liu KH 

PROVIDER: S-EPMC8822346 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature