Synthetic biology with cyanobacteria: genetic capacity to produce antimicrobial peptides and trans-resveratrol in Synechocystis sp. PCC 6803

Abstract

Phototrophic cyanobacteria are attractive candidates for heterologous production of numerous enzymes and bioactive products due to the recent progress in design and genetic engineering of selected model strains. In this study, the capability of cyanobacteria for producing plant defensin, a class of antimicrobial peptide, and trans-resveratrol production was evaluated using the two different promoters Ptrc1Ocore and Ptrc1O.

The in silico and gene coexpression network analyses were performed to identify rice defensins, OsDEF7 and OsDEF8 that are coexpressed with pathogen-responsive genes. Both recombinant peptides were heterologously produced in Escherichia coli as dimer that exhibited significant inhibitory activities against several plant pathogens. Although their gene expressions were detected in Synechocystis PCC 6803, the recombinant peptides were not found.

The heterologous expression of enzymes involved in the trans-resveratrol production, namely tyrosine ammonia-lyase, coumaroyl CoA ligase, and stilbene synthase, were also performed in Synechocystis PCC 6803. The respective genes were expressed and translated to soluble proteins under both promoters. p-Coumaric acid was detected in both in vitro and in vivo reactions. However, trans-resveratrol could not be detected. Nevertheless, these results provide valuable information toward developing cyanobacteria as an alternative host.