title: The plastid genome of some eustigmatophyte algae harbours a bacteria-derived six-gene cluster for biosynthesis of a novel secondary metabolite.
abstract: Acquisition of genes by plastid genomes (plastomes) via horizontal gene transfer (HGT) seems to be a rare phenomenon. Here, we report an interesting case of HGT revealed by sequencing the plastomes of the eustigmatophyte algae Monodopsis sp. MarTras21 and Vischeria sp. CAUP Q 202. These plastomes proved to harbour a unique cluster of six genes, most probably acquired from a bacterium of the phylum Bacteroidetes, with homologues in various bacteria, typically organized in a conserved uncharacterized putative operon. Sequence analyses of the six proteins encoded by the operon yielded the following annotation for them: (i) a novel family without discernible homologues; (ii) a new family within the superfamily of metallo-dependent hydrolases; (iii) a novel subgroup of the UbiA superfamily of prenyl transferases; (iv) a new clade within the sugar phosphate cyclase superfamily; (v) a new family within the xylose isomerase-like superfamily; and (vi) a hydrolase for a phosphate moiety-containing substrate. We suggest that the operon encodes enzymes of a pathway synthesizing an isoprenoid-cyclitol-derived compound, possibly an antimicrobial or other protective substance. To the best of our knowledge, this is the first report of an expansion of the metabolic capacity of a plastid mediated by HGT into the plastid genome.
authors.affiliation: Faculty of Science, Department of Biology and Ecology, Life Science Research Centre, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic.|Faculty of Science, Institute of Environmental Technologies, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Yurchenko
authors.affiliation: Faculty of Science, Department of Biology and Ecology, Life Science Research Centre, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic.
authors.forename: Tereza
authors.initials: T
authors.lastname: Ševčíková
authors.affiliation: Institute of Molecular Genetics of the ASCR, v. v. i., Prague, Czech Republic.
authors.forename: Hynek
authors.initials: H
authors.lastname: Strnad
authors.affiliation: Faculty of Science, Department of Biology and Ecology, Life Science Research Centre, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic.
authors.forename: Anzhelika
authors.initials: A
authors.lastname: Butenko
authors.affiliation: Faculty of Science, Department of Biology and Ecology, Life Science Research Centre, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic marek.elias@osu.cz.|Faculty of Science, Institute of Environmental Technologies, University of Ostrava, Chittussiho 10, 710 00 Ostrava, Czech Republic.
authors.forename: Marek
authors.identifier: 0000-0003-0066-6542
authors.initials: M
authors.lastname: Eliáš
mesh_terms: D048028:DNA, Algal / Q000235:genetics; D019143:Evolution, Molecular; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D054627:Genome, Plastid; D058977:Molecular Sequence Annotation; D005810:Multigene Family; D017422:Sequence Analysis, DNA / Q000379:methods*; D058009:Stramenopiles / Q000235:genetics*
chemical_list: D048028:DNA, Algal
keywords: Eustigmatophyceae; UbiA superfamily; horizontal gene transfer; plastid genome; secondary metabolism; sugar phosphate cyclase superfamily