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Hfq is important for biofilm formation, motility and pathogenicity of the plant pathogen Pantoea ananatis

Gi Yoon Shin: Centre for Microbial Ecology and Genomics, University of Pretoria


<div>Bacterial phytopathogens constantly encounter changing environmental conditions. To ensure their survival and persistence, they rapidly respond to a change by modulating gene expression, resulting in an altered phenotype. The RNA chaperone Hfq is the key protein that controls the gene expression at the post-transcriptional level through mediating a regulatory interaction between the small RNA with its target messenger RNA. The outcome of this regulation allows the bacterium to adapt to change accordingly. <em>Pantoea ananatis</em> is a versatile plant pathogen of many agro-economically important plant species including corn, onion, rice, pineapple, melon and <em>Eucalyptus</em> and its motility and ability to form biofilm helps the pathogen to infect and proliferate in its plant host. The bacterium is also found in a diverse range of ecological niche as a saprophyte and epi- or endophyte. We hypothesize that the versatility of <em>P. ananatis</em> in infecting and colonizing different hosts and environments may be attributed to rapid Hfq-mediated response to various environmental conditions. Thus the functional role of Hfq was investigated by constructing an <em>hfq </em>deletion mutant of <em>P. ananatis</em> LMG 2665<sup>T</sup> and the effect of the mutation in biofilm formation, motility and pathogenicity was characterized. An <em>hfq</em> null mutant displayed significantly decreased biofilm production and motility and there was an absence of pathogenicity on onion seedlings .The findings suggest that Hfq is an important regulator of biofilm formation, motility and pathogenicity in <em>P. ananatis,</em> providing an insight into functional roles of Hfq in this versatile plant pathogen<em>.</em></div>