title: Loss of cytochrome cM stimulates cyanobacterial heterotrophic growth in the dark.
abstract: Although cyanobacteria are photoautotrophs, they have the capability for heterotrophic metabolism that enables them to survive in their natural habitat. However, cyanobacterial species that grow heterotrophically in the dark are rare. It remains largely unknown how cyanobacteria regulate heterotrophic activity. The cyanobacterium Leptolyngbya boryana grows heterotrophically with glucose in the dark. A dark-adapted variant dg5 isolated from the wild type (WT) exhibits enhanced heterotrophic growth in the dark. We sequenced the genomes of dg5 and the WT to identify the mutation(s) of dg5. The WT genome consists of a circular chromosome (6,176,364 bp), a circular plasmid pLBA (77,793 bp) and two linear plasmids pLBX (504,942 bp) and pLBY (44,369 bp). Genome comparison revealed three mutation sites. Phenotype analysis of mutants isolated from the WT by introducing these mutations individually revealed that the relevant mutation is a single adenine insertion causing a frameshift of cytM encoding Cyt c(M). The respiratory oxygen consumption of the cytM-lacking mutant grown in the dark was significantly higher than that of the WT. We isolated a cytM-lacking mutant, ΔcytM, from another cyanobacterium Synechocystis sp. PCC 6803, and ΔcytM grew in the dark with a doubling time of 33 h in contrast to no growth of the WT. The respiratory oxygen consumption of ΔcytM grown in the dark was about 2-fold higher than that of the WT. These results suggest a suppressive role(s) for Cyt cM in regulation of heterotrophic activity.
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan.
authors.forename: Yuto
authors.initials: Y
authors.lastname: Hiraide
authors.affiliation: Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, 277-8561 Japan.
authors.forename: Kenshiro
authors.initials: K
authors.lastname: Oshima
authors.affiliation: Center for Information Biology, National Institute for Genetics, Research Organization of Information and Systems, Yata, Mishima, 411-8540 Japan.
authors.forename: Takatomo
authors.initials: T
authors.lastname: Fujisawa
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Uesaka
authors.affiliation: Electronics-Inspired Interdisciplinary Research Institute, Toyohashi University of Technology, 1-1 Hibarigaoka Tempaku, Toyohashi, Aichi, 441-8580 Japan.
authors.forename: Yuu
authors.initials: Y
authors.lastname: Hirose
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan.
authors.forename: Ryoma
authors.initials: R
authors.lastname: Tsujimoto
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan Present address, Institute for Protein Research, Osaka University, Osaka, Japan.
authors.forename: Haruki
authors.initials: H
authors.lastname: Yamamoto
authors.affiliation: Database Center for Life Sciences, Research Organization of Information and Systems, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032 Japan.
authors.forename: Shinobu
authors.initials: S
authors.lastname: Okamoto
authors.affiliation: Center for Information Biology, National Institute for Genetics, Research Organization of Information and Systems, Yata, Mishima, 411-8540 Japan.
authors.forename: Yasukazu
authors.initials: Y
authors.lastname: Nakamura
authors.affiliation: Department of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577 Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Terauchi
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan CREST, Japan Science and Technology Agency, Kawaguchi, Saitama, 332-0012 Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Omata
authors.affiliation: Center for Gene Research, Nagoya University, Nagoya, 46-8602 Japan.
authors.forename: Kunio
authors.initials: K
authors.lastname: Ihara
authors.affiliation: Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba, 277-8561 Japan.
authors.forename: Masahira
authors.initials: M
authors.lastname: Hattori
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, 464-8601 Japan fujita@agr.nagoya-u.ac.jp.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Fujita
mesh_terms: D001483:Base Sequence; D000458:Cyanobacteria / Q000235:genetics* / Q000254:growth & development*; D045304:Cytochromes c / Q000235:genetics*; D003624:Darkness; D015321:Gene Rearrangement; D016680:Genome, Bacterial; D052836:Heterotrophic Processes / Q000235:genetics*; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D010802:Phylogeny; D046939:Synechocystis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D014170:Transformation, Genetic
chemical_list: D045304:Cytochromes c
keywords: Cyanobacteria; Cytochrome cM; Heterotrophic growth; Leptolyngbya boryana; Synechocystis sp. PCC 6803; cytM