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Oral: Bacterial Virulence Regulation


Determination of CsrA/RsmA regulon in Xanthomonas citri subsp. citri
M. ANDRADE (1) (1) Dept. Microbiology and Cell Science, CREC- University of Florida, U.S.A.

In bacteria, it is poorly understood how post-transcriptional regulation mediated by RNA-binding proteins contributes to adaptation to environment changes during host infection. RsmA (Regulator of secondary metabolism) is a small RNA-binding protein that plays an important role in regulation of pathogenicity, motility, biofilm formation, endoglucanases and exopolysaccharide production in Xanthomonas citri subsp. citri (Xcc). In previous work, we showed that RsmA contributes to the pathogenicity by activating expression of genes encoding the type 3 secretion system (T3SS) and effectors in Xcc. However, the mechanistic understanding of Xcc RsmA in regulating motility, biofilm formation and production of exopolysaccharide and endoglucanases remains unclear. We have performed crosslinking and affinity purification followed by RNAseq analysis in order to determine the RsmA targets in Xcc cells in both rich medium and a T3SS-inducing medium. Our data revealed hundreds of putative binding mRNA targets in Xcc. Functional classification (Gene Ontology) of RsmA mRNA targets suggests Xcc RsmA is a global RNA-binding regulator that can positively and negatively affect the expression of genes in Xanthomonas.