Molecular characterization of a moss isoprene synthase provides insight into its evolution

This is the first report on the molecular characterization of isoprene synthase (ISPS) from the moss Calohypnum plumiforme. After isoprene emission from C. plumiforme was confirmed, the cDNA encoding C. plumiforme ISPS (CpISPS) was narrowed down using a genome database associated with protein structure prediction, and a CpISPS gene was identified. The recombinant CpISPS, produced in Escherichia coli, converted dimethylallyl diphosphate to isoprene. Phylogenetic analysis indicated similarity between the amino acid sequences of CpISPS and moss diterpene cyclases (DTCs) but not ISPSs of higher plants, implying that CpISPS is derived from moss DTCs and is evolutionarily unrelated to canonical ISPSs of higher plants. CpISPS is a novel class I cyclase of the terpene synthase-c subfamily harboring & alpha;& beta; domains. This study will help further study of isoprene biosynthesis and the physiological functions of isoprene in mosses.

Automated summary

This study reports the molecular characterization of isoprene synthase (ISPS) from the moss Calohypnum plumiforme. The cDNA encoding CpISPS was identified and the recombinant CpISPS produced in Escherichia coli was found to convert dimethylallyl diphosphate to isoprene. Phylogenetic analysis revealed that CpISPS is derived from moss diterpene cyclases (DTCs) and is evolutionarily unrelated to ISPSs of higher plants. CpISPS is a novel class I cyclase of the terpene synthase-c subfamily. This study contributes to the understanding of isoprene biosynthesis and the physiological functions of isoprene in mosses.