Tricarboxylic acid cycle activity regulates tomato root growth via effects on secondary cell wall production.
Plant Physiol
; 153(2): 611-21, 2010 Jun.
Article
en En
| MEDLINE
| ID: mdl-20118274
ABSTRACT
Transgenic tomato (Solanum lycopersicum 'Moneymaker') plants independently expressing fragments of various genes encoding enzymes of the tricarboxylic acid cycle in antisense orientation have previously been characterized as exhibiting altered root growth. In this study, we evaluate the rates of respiration of roots from these lines in addition to determining their total dry weight accumulation. Given that these features were highly correlated, we decided to carry out an evaluation of the cell wall composition in the transformants that revealed a substantial reduction in cellulose. Since the bulk of cellulose is associated with the secondary cell walls in roots, we reasoned that the transformants most likely were deficient in secondary wall cellulose production. Consistent with these findings, cross-sections of the root collar (approximately 15 mm from the junction between root and stem) displayed reduced lignified secondary cell walls for the transformants. In contrast, cell and cell wall patterning displayed no differences in elongating cells close to the root tip. To further characterize the modified cell wall metabolism, we performed feeding experiments in which we incubated excised root tips in [U-(14)C]glucose in the presence or absence of phosphonate inhibitors of the reaction catalyzed by 2-oxoglutarate dehydrogenase. Taken together, the combined results suggest that restriction of root respiration leads to a deficit in secondary cell wall synthesis. These data are discussed in the context of current models of biomass partitioning and plant growth.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Pared Celular
/
Ciclo del Ácido Cítrico
/
Solanum lycopersicum
/
Raíces de Plantas
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Plant Physiol
Año:
2010
Tipo del documento:
Article
País de afiliación:
Alemania