Characterization of small regulatory RNAs with a putative function in the virulence of Xanthomonas campestris pv. vesicatoria

• Applicant: Professorin Dr. Ulla Bonas
• Subject Area: Plant Genetics and Genomics
• Term: from 2007 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 40424276

Pathogenicity of the Gram-negative plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria (Xcv) depends on the type III secretion system (T3SS), which injects effector proteins into the host cell cytosol. The T3SS is specifically activated in planta by two regulatory proteins, HrpG and HrpX. HrpG controls expression of a genome-wide regulon which is also affected by small RNAs (sRNAs) that modulate bacterial virulence. In the first funding period, deep sequencing, bioinformatics and Northern analyses of the transcriptome of Xcv strain 85-10 identified 27 sRNAs. One example is sR72, a highly structured sRNA, which is required for full virulence and presumably acts upstream of HrpG. Furthermore, additional sRNAs and cis-encoded antisense RNAs with a virulence function were experimentally identified. In the proposed project we aim at the functional characterization of selected sRNAs from Xcv and the identification of their targets. In addition, selected cis-encoded antisense RNAs and the RNA-binding proteins Hfq and CsrA will be characterized genetically and on the molecular level. These approaches should help to elucidate the mechanisms that control virulence of Xcv on the posttranscriptional level.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1258: Sensory and Regulatory RNAs in Prokaryotes