Pantoea ananatis carotenoid production confers toxoflavin tolerance and is regulated by Hfq ‐controlled quorum sensing

Carotenoid production confers tolerance to toxoflavin and UV radiation inPantoea ananatis. We proposed a model of carotenoid production for the previously reported regulatory network HfqArcZ→ RpoS Ͱ ClpXP and that identified here, in which Hfq‐controlled quorum signaling derepresses EanR to activate RpoS expression, thereby initiating carotenoid production. AbstractCarotenoids are widely used in functional foods, cosmetics, and health supplements, and their importance and scope of use are continuously expanding. Here, we characterized carotenoid biosynthetic genes of the plant ‐pathogenic bacteriumPantoea ananatis, which carries a carotenoid biosynthetic gene cluster (includingcrtE,X,Y,I,B, andZ) on a plasmid. Reverse transcription –polymerase chain reaction (RT‐PCR) analysis revealed that thecrtEXYIB gene cluster is transcribed as a single transcript andcrtZ is independently transcribed in the opposite direction. Using splicing by overlap extension with polymerase chain reaction (SOE by PCR) based on asymmetric amplification, we reassembledcrtE–B,crtE–B–I, andcrtE–B–I–Y. High ‐performance liquid chromatography confirmed thatEscherichia coli expressing the reassembledcrtE–B,crtE–B–I, andcrtE–B–I–Y operons produced phytoene, lycopene, and β‐carotene, respectively. We found that the carotenoids conferred tolerance to UV radiation and toxoflavin.Pantoea ananatis shares rice environments with the toxoflavin producerBurkholderia glumae and i...
Source: MicrobiologyOpen - Category: Microbiology Authors: Tags: ORIGINAL ARTICLE Source Type: research