An intact plastid genome is essential for the survival of colorless Euglena longa but not Euglena gracilis.
Curr Genet
; 63(2): 331-341, 2017 May.
Article
em En
| MEDLINE
| ID: mdl-27553633
ABSTRACT
Euglena gracilis growth with antibacterial agents leads to bleaching, permanent plastid gene loss. Colorless Euglena (Astasia) longa resembles a bleached E. gracilis. To evaluate the role of bleaching in E. longa evolution, the effect of streptomycin, a plastid protein synthesis inhibitor, and ofloxacin, a plastid DNA gyrase inhibitor, on E. gracilis and E. longa growth and plastid DNA content were compared. E. gracilis growth was unaffected by streptomycin and ofloxacin. Quantitative PCR analyses revealed a time dependent loss of plastid genes in E. gracilis demonstrating that bleaching agents produce plastid gene deletions without affecting cell growth. Streptomycin and ofloxacin inhibited E. longa growth indicating that it requires plastid genes to survive. This suggests that evolutionary divergence of E. longa from E. gracilis was triggered by the loss of a cytoplasmic metabolic activity also occurring in the plastid. Plastid metabolism has become obligatory for E. longa cell growth. A process termed "intermittent bleaching", short term exposure to subsaturating concentrations of reversible bleaching agents followed by growth in the absence of a bleaching agent, is proposed as the molecular mechanism for E. longa plastid genome reduction. Various non-photosynthetic lineages could have independently arisen from their photosynthetic ancestors via a similar process.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Plastídeos
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Euglena longa
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Euglena gracilis
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Genomas de Plastídeos
Idioma:
En
Revista:
Curr Genet
Ano de publicação:
2017
Tipo de documento:
Article