Producción CyT
Acetoacetyl-CoA thiolase regulates mevalonate pathway during abiotic stress adaptation
Articulo
Autoría:
SOTO, GABRIELA CYNTHIA ; Margarita Stritzler ; Christian Lisi ; Karina Alleva ; Maria Elba Pagano ; Fernando Ardila ; Matteo Mozzicafreddo ; Massimiliano Cuccioloni ; Mauro Angeletti ; Nicolas Daniel AyubFecha:
2011Editorial y Lugar de Edición:
OXFORD UNIV PRESSRevista:
JOURNAL OF EXPERIMENTAL BOTANY, vol. 62 (pp. 5699-5711) OXFORD UNIV PRESSResumen *
Acetoacetyl-CoA thiolase (EC 2.3.1.9), also called thiolase II, condenses two molecules of acetyl-CoA to give acetoacetyl-CoA. This is the first enzymatic step in the biosynthesis of isoprenoids via mevalonate (MVA). In this work, thiolase II from alfalfa (MsAACT1) was identified and cloned. The enzymatic activity was experimentally demonstrated in planta and in heterologous systems. The condensation reaction by MsAACT1 was proved to be inhibited by CoA suggesting a negative feedback regulation of isoprenoid production. Real-time RT-PCR analysis indicated that MsAACT1 expression is highly increased in roots and leaves under cold and salinity stress. Treatment with mevastatin, a specific inhibitor of the MVA pathway, resulted in a decrease in squalene production, antioxidant activity and survival of stressed plants. As expected, the presence of mevastatin did not change in chlorophyll and carotenoid levels, isoprenoids synthesized via the plastidial MVA-independent pathway. Addition of vitamin C suppressed the sensitive phenotype of plants challenged with mevastatin, suggesting a critical function of the MVA pathway in abiotic stress-inducible antioxidant defense. MsAACT1 overexpressing transgenic plants showed salinity tolerance comparable with empty vector transformed plants and enhanced production of squalene without altering the 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) activity in salt-stress conditions. Thus, acetoacetyl-CoA thiolase is a regulatory enzyme in isoprenoid biosynthesis involved in abiotic stress adaptation. Información suministrada por el agente en SIGEVAPalabras Clave
MVA pathwayisoprenoidabiotic stressthiolase II