Regulation of Nicotine Biosynthesis by an Endogenous Target Mimicry of MicroRNA in Tobacco.
Plant Physiol
; 169(2): 1062-71, 2015 Oct.
Article
en En
| MEDLINE
| ID: mdl-26246450
ABSTRACT
The interaction between noncoding endogenous target mimicry (eTM) and its corresponding microRNA (miRNA) is a newly discovered regulatory mechanism and plays pivotal roles in various biological processes in plants. Tobacco (Nicotiana tabacum) is a model plant for studying secondary metabolite alkaloids, of which nicotine accounts for approximately 90%. In this work, we identified four unique tobacco-specific miRNAs that were predicted to target key genes of the nicotine biosynthesis and catabolism pathways and an eTM, novel tobacco miRNA (nta)-eTMX27, for nta-miRX27 that targets QUINOLINATE PHOSPHORIBOSYLTRANSFERASE2 (QPT2) encoding a quinolinate phosphoribosyltransferase. The expression level of nta-miRX27 was significantly down-regulated, while that of QPT2 and nta-eTMX27 was significantly up-regulated after topping, and consequently, nicotine content increased in the topping-treated plants. The topping-induced down-regulation of nta-miRX27 and up-regulation of QPT2 were only observed in plants with a functional nta-eTMX27 but not in transgenic plants containing an RNA interference construct targeting nta-eTMX27. Our results demonstrated that enhanced nicotine biosynthesis in the topping-treated tobacco plants is achieved by nta-eTMX27-mediated inhibition of the expression and functions of nta-miRX27. To our knowledge, this is the first report about regulation of secondary metabolite biosynthesis by an miRNA-eTM regulatory module in plants.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Nicotiana
/
MicroARNs
/
Nicotina
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Plant Physiol
Año:
2015
Tipo del documento:
Article