Genetic engineering of Escherichia coli to enhance biological production of vanillin from ferulic acid

Escherichia coli is considered a good host for the production of vanillin from phytochemicals, such as ferulic acid. A major drawback of this vanillin-producing system is the genetic instability of E. coli recombinant strains bearing genes encoding feruloyl-CoA synthetase and feruloyl-CoA hydratase/aldolase. In this work, the possibility to develop a more stable strain was explored by integrating into the E. coli chromosome the Pseudomonas fluorescens genes encoding these two enzymes. The resulting strain, named FR13, was more efficient in vanillin production than strains expressing the same genes from a low copy plasmid vector

Involvement of a hypersensitive-like reaction in tolerance to fire blight in pear (pyrus communis L.)

Infection by Erwinia amylovora, the causal agent of fire blight (FB) disease, induces in apple and pear host plants, the generation of reactive oxygen species (ROS). We analyzed at molecular level, the link between ROS production and susceptibility to bacterial infection. Gene expression time course showed that expression of chloroplast, mitochondrial and nuclear genes, whose transcription is redox-dependent, was down regulated or suppressed in tolerant cultivar, Harrow Sweet, in comparison with susceptible cultivar, Williams. Monitoring of oxidative burst by localization of hydrogen peroxide showed that oxidative burst was triggered faster in tolerant cultivar in response to infection. These results suggest that transcription of some redox-dependent genes of cytoplasmic organelles and nucleus, in the two cultivars, is regulated faster in the tolerant cultivar than in the susceptible one.Keywords: Chloroplast, electron transport Chain, Erwinia amylovora, mitochondria, Pyrus communis, redoxAfrican Journal of Biotechnology, Vol 13(28) 2840-284